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Jun 19, 2017 - Pavia, Italy --- Rehabilitation Design of Ex.Certosina of Palazzo Botta ... Progetto di riabilitazione della Ex.Certosina del Palazzo Botta in tre.
UNIVERSITA’ DEGLI STUDI DI PAVIA FACOLTA’ DI INGEGNERIA DIPARTIMENTO DI INGEGNERIA CIVILE ED ARCHITETTURA CORSO DI LAUREA MAGISTRALE IN INGEGNERIA EDILE - ARCHITETTURA

TESI DI LAUREA Material and Craft Study of Diachronic Interface in Old Architecture Rehabilitation --- Reuse and Improvement Design of Ex. Certosina of Palazzo Botta Studio Materiale e Artigianale per Interfaccia Diacronica della Riabilitazione di Costruzioni Anticheo --- Riutilizzo e miglioramento della progettazione di Ex. Certosina di Palazz Botta

Candidato: SHEN Yue Relatore: Prof. Tiziano CATTANEO Relatore: Prof. Daniela BESANA Correlatore: Prof. ZHANG Ming

A.A. 2016/2017

Abstract In terms of old building rehabilitation, the main issue is how to deal with the relation between old and new while the diachronic interface is the specific study object which is prominently reflected on the tectonic relation of the material and craft. As a result, the present thesis which is based on the analyses of the diachronic interfaces of modern and contemporary rehabilitation cases in Western Europe, preliminary concludes some concrete design solutions as well as global design methods of the material and craft, which are also utilized and proved in the subsequent design project. For “diachronic interface”, two main inherent concepts: diachronic continuity and synchronic connection, are raised firstly. Then, about “material and craft”, according to tremendous document and case studies, three pivotal layers from “old ”to “new”: existing materials and crafts, interventional materials and interventional crafts, are dissected transitively, which establish a relation organization and expression of different types of diachronic interfaces (structure, construction, configuration) based on corresponding crafts of one-to-one materials. In addition, some inferences from the analyses, like the origins of diachronic interfaces (damage of the structure, lack of the enclosure, alteration of the space) and the factors of diachronic interfaces (time, district, function and architect preference), also have certain impact on the forming of design methods. Thence, through incorporating them together, three global design principles (appropriate material use, harmonious relation expression, uniformly differential design technique) and four concrete design steps (investigate existing materials and crafts, estimate positions and types of diachronic interfaces, select interventional materials according to factors, design particular crafts for diachronic interfaces) are concluded, which are further elaborated through the design projects in Pavia, Italy --- Rehabilitation Design of Ex.Certosina of Palazzo Botta from three different scales (urban and site scale, architectural scale and material and craft scale) to excavate and develop the specific design of three different types of diachronic interfaces involved: Brick Portico Space (Structural Interface), Vertical Glass Box (Constructional Interface), and Suspended Metal Bridge (Configurational Interface).Thus, the design process fully explained how different factors from different scales affect the material selection and craft consideration of a certain diachronic interface in a real complicated situation and how a correct design of a diachronic interface reflects both the physical connection and historical continuity behind it. Finally, the deficiencies and limitations of the whole research process are evaluated and some relative subsequent researches are also mentioned.

Key Words: old building rehabilitation, diachronic interface, material and craft, Western Europe

II

Riassunto Quando si parla di riabilitazione di edifici antichi, il problema principale riguarda il rapporto tra l’antico e nuovo, mentre l’interfaccia diacronica è l’oggetto si studio specifico che si riflette nella relazione tettonica del materiale e dell’artigianato. Come risultato, lo scopo principale della tesi, che si basa sulle analisi delle interfacce diacroniche dei casi di riabilitazione moderna e contemporanea in Europa occidentale, consiste in soluzioni di progettazione in calcestruzzo e in metodi di progettazione globale del materiale e dell’artigianato, i quali vengono utilizzati e mostrati nei seguente progetto. Con il termine di “interfaccia diacronica”, bisogna considerare due concetti fondamentali: la continuità diacronica e la connessione sincronica. Per quanto riguarda I “materiali” e “artigianato”, in base a documenti importanti e diversi casi studio, ci sono tre strati centrali che si susseguono da “vecchio” a “nuovo”: materiali e artigianato esistenti e di intervento sono analizzati transitivamente e stabiliscono una relazione di organizzazione e espressione di diversi tipi di interfacce diacroniche (struttura, costruzione, configurazione), basata su corrispondenti artigianati di materiali. Inoltre, alcune interferenze delle analisi, come per esempio le origini delle interfacce diacroniche (danni della struttura, mancanza di chiusura, alterazione dello spazio) e i fattori delle interfacce diacroniche (tempo, distretto, funzione e preferenze architetto), hanno anche un certo impatto sulla formazione di metodi di progettazione. Quindi, attraverso l'inserimento di tre principi di progettazione globale (uso del materiale appropriato, espressione armoniosa di relazioni, abilità di progettazione differenziata) e quattro fasi di progettazione concreti (ricerca di materiali e di oggetti esistenti, valutazione delle posizioni e delle tipologie di interfacce diacroniche, selezione di materiali a seconda dei fattori, progettazione di particolari artigianati di interfacce diacroniche) sono stati sviluppati approfonditamente in diversi progetti di Pavia, Italia --- Progetto di riabilitazione della Ex.Certosina del Palazzo Botta in tre diverse scale (scala urbana e del sito, scala architettonica e materiale) per sviluppare la progettazione specifica di tre diversi tipi di interfacce diacroniche coinvolte: Spazio del portico in mattoni Brick Portico Space (Interfaccia Strutturale), Cassetta Vetrata Verticale (Interfaccia di costruzione) e Ponte sospeso Di Metallo (Interfaccia di configurazione). Quindi il processo di progettazione ha analizzato come i diversi fattori di diversi livelli influenzano la selezione del materiale e la considerazione artigianale di una certa interfaccia diacronica in una vera e propria situazione complicata e come un corretto progetto di un'interfaccia diacronica riflette sia la connessione fisica che la continuità storica. Infine, le carenze e le limitazioni di tutto il processo di ricerca sono state valutate e allo stesso tempo sono state citate alcune ricerche successive.

Parole chiave: riabilitazione di costruzioni antiche, interfaccia diacronica, materiale e artigianato, Europa occidentale

II

Content INTRODUCTION █ Research Background █ Study Problems and Aims █ Study Range and Definitions █ Thesis Outline and Methodology

8 10 12 17

PART I THEORY CHAPTER 01: EXISTING MATERIALS AND CRAFTS █ 1.1 General Categories ● 1.1.1 Structural Materials and Crafts ● 1.1.2 Cladding Materials and Crafts █ 1.2 Main Problems (Origins of Diachronic Interface) ● 1.2.1 Damage of the Structure ● 1.2.2 Lack of the Enclosure ● 1.2.3 Alteration of the Space CHAPTER 02: INTERVENTIONAL MATERIALS █ 2.1 General Categories ● 2.1.1 Structural Materials ● 2.1.2 Cladding Materials ● 2.1.3 Dual (Attributes) Materials █ 2.2 Selecting Factors ● 2.2.1 Times Developments ● 2.2.2 Regional Differences ● 2.2.3 Functional Requirements ● 2.2.4 Architect Preferences CHAPTER 03: INTERVENTIONAL CRAFTS █ 3.1 Structural Interface ● 3.1.1 For Masonry Structure ● 3.1.2 For Reinforced Concrete Structure ● 3.1.3 For Iron or Steel Structure ● 3.1.4 For Wood Structure █ 3.2 Constructional Interface ● 3.2.1 For Masonry Structure ● 3.2.2 For Reinforced Concrete Structure ● 3.2.3 For Iron or Steel Structure ● 3.2.4 For Wood Structure █ 3.2 Configurational Interface ● 3.3.1 For Masonry Surface ● 3.3.2 For Plaster Surface

20

38

42

48

59

77

92

4

● 3.3.3 For Glass Surface ● 3.3.4 For Ceramic Roof Tile Surface PART II DESIGN CHAPTER 04: DESIGN METHODS █ 4.1 General Principles ●4.1.1 Appropriate Material Utilization ●4.1.2 Harmonious Relation Expression ●4.1.3 Uniformly Differential Design Technique █ 4.2 Specific Steps ●4.2.1 Investigate Existing Materials and Crafts ●4.2.2 Estimate Positions and Types of Diachronic Interfaces ●4.2.3 Select interventional materials according to Factors ●4.2.4 Design Particular Crafts for Diachronic Interfaces CHAPTER 05: DESIGN PROJECT █ 5.1 Urban and Site Scales ● 5.1.1 Urban Context and Strategies ● 5.1.2 Site Concepts and Plans █ 5.2 Architecture Scale ● 5.2.1 Background Analyses ● 5.2.2 Rehabilitation Concepts

102

104

108

123

● 5.2.3 Spatial Designs █ 5.3 Material and Craft Scale ● 5.3.1 Preliminary Evaluation ● 5.3.2 Determination of Diachronic Interfaces ● 5.3.3 Material Selections and Craft Designs 5.3.3.1 Structural Interface – Brick Portico Space 5.3.3.2 Constructional Interface – Vertical Glass Box 5.3.3.3 Configurational Interface – Suspended Metal Bridge CONCLUSIONS AND PERSPECTIVES █ Final Conclusions █ Further Perspectives

132

146 148

Acknowledgements Bibliography Appendix

150 152 155

IV

INTRODUCTION

INTRODUCTION

█ RESEARCH BACKGROUND ● OLD BUILDING REHABILITATION Building intervention has a long history. Whether it is the ancient Greek Temple in honor of the god of Earth was converted into the Christian Church for the statue of Jesus, or the ancient Roman city wall defending the invasion of foreign enemies was reused as the military fortress for station troops, or even the royal palace holding the nobles was transformed to be the gallery museum to exhibit priceless treasures, the process of any physical change of the building will be alternately flashed in different times, and slowly changing with the demands of the users. However, unlike the large and complex practical architectural field of building intervention1, the real core of the discussion here about the old building rehabilitation is on the cognition and treatment of the word ‘old’. Therefore, the first thing that needs to be clear is what the old building is. By sorting out the relevant literatures in contemporary and modern times (Table 0-1), it is found that the term ‘old building’ is gradually formed and defined in the study of ‘old and new relationships’ that aroused in the recent years. Compared to those concepts which came out more from the historical protection in the first half of the 20th century, such as ‘historic building’, the range of ‘old building’ is relatively much broader, which includes any left building with a certain history and cultural and artistic values. However, compared to ‘historic monument’ or ‘historic and architectural areas’, it seems relatively narrower, which only involves individual building and building complex, without large building groups, urban or rural areas and other large objects. Table 0-1 Significant Concepts related to “old building” Literature

Times

Explanation of Concepts

The Athens Charter

1933

‘Legacy of historic’: Fine architecture, whether individual buildings or groups of buildings, should be protected from demolition. The grounds for the preservation of buildings should be that they express an earlier culture and that their retention is in the public interest.

The Venice Charter

1964

‘Historic monument’ embraces not only the single architectural work but also the urban or rural setting in which is found the evidence of a particular civilization, a significant development or a historic event. This applies not only to great works of art but also to more modest works of the past which have acquired cultural significance with the passing of time.

Nairobi

1976

Recommendation

`Historic and architectural (including vernacular) areas' shall be taken to mean any groups of buildings, structures and open spaces including archaeological and palaeontological sites, constituting human settlements in an urban or rural environment, the cohesion and value of which, from the archaeological, architectural, prehistoric, historic, aesthetic or sociocultural point of view are recognized

Architecture in Context: Fitting New

1988

‘Old building’ includes the ordinary buildings nearby, the regional stylish buildings, the old place symbols, monumental buildings and so on.

Buildings with Old

1

As is mentioned at the beginning of the book ‘Architecture Reborn: The Conversion and Reconstruction of Old Buildings’ by Kenneth Powell, ’Reusing existing buildings is, first and foremost, a matter of common-sense economics and it is a process which has gone on throughout history……The driving force behind reuse was, in other words, functional and financial.’. As a result, building intervention doesn’t take too much consideration of or show respect for the original characters and properties of the existing building, which shows a large difference from the diachronic issue discussed in this thesis. 8

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

After the clarification of this definition, then we can really explain the research background of ‘old building rehabilitation’. Compared with the theoretical study of the historical relic protection and repair brought about with the rise of archaeology at the beginning of the 19th century, it is believed that the large-scale development and practice of the old building rehabilitation mainly began and were throughout the 20th century. This is mainly due to several reasons: first of all, the occurrence of two World Wars led to the damages of many unique historical towns and buildings, which foreshadowed the reconstruction and repair afterwards; secondly, the invasion of the Modernism on a large scale the caused irreversible damages to the typical urban texture, which made more general old buildings begin to get the public attention; In addition, the transformation of industrial buildings and the lack of ecological resources brought about by the Oil Crisis in 1970s, also strengthened the perception of the sustainable development and reuse of old buildings in society. In the 1980s and 1990s, with the rise of the Postmodernism and the Urban Revival Movement, more and more old building rehabilitations began to focus on the issue about the continuation of the urban interface and were closely related to the lives of the ordinary people. Therefore, in terms of European Countries and the United States which enjoy almost 100-year developing history of the old building rehabilitation, there are a large number of practical examples and cases of different styles during different periods which can be utilized to carry out a quite complete analysis and study. ● MATERIAL AND CRAFT In the field of architecture, the practice and attention to materials and crafts are always changing with the times. The application of a large amount of cast iron and wrought iron in the construction after the Industrial Revolution, completely broke the traditional solid masonry wall, forming a large open and vast glass space; and The development of the reinforced concrete molding technology and shell structure after the Modernism, also changed the normal square volume into a beautiful and reasonable large-span space; with the continuous development of the sustainable conception and the environmental protection technology, more and more new energy-efficient and recycling materials began to attract people's attention. The earliest description of the material and craft is from The Ten Books on Architecture that was written by Vitruvius during the ancient Roman period. Inside the book, Vitruvius regards the producing craft as an inseparable element with the properties of the material, which is to say, the nature of the material is demonstrated through the craft process, therefore at this time the material is only played a simple role in construction and imitates the nature through the craft. But till the Renaissance, due to the refinement and technology development of the stone producing craft, the cladding stone began to appear. Thus, the material was given a new mission - decoration. Since then, with the arrival of the Enlightenment and the Material Scientific Development, the authenticity of materials became an important issue. In this regard, both Claude Perrault and Carlo Lodoli argued that the form of the material should be consistent with its attributes and represent it through the craft. And this kind of craft concept which was based on the material performance passed on from the 18th century to the 19th century, and formed the Structural Rationalism later. At the same time, however, according to Gottfried Semper, there was a completely different path: the theory of Surface Decoration2, and influenced Adolf Loos later in the early 20th century with 2 According to Semper’s archaeological research at that time, the ancient Greek architecture covered its original materials and structure through the "Dressing" theory. At the same time, the cladding surface for decorations

9

INTRODUCTION

the concept of expressing emotions through sensible decorative claddings. At this point, the design expression of the material and craft has shown a diversified trend. With the development of Science and Technology after the 20th century, more and more extensive materials and crafts have been applied to the building construction, which not only formed the material system based on the years of construction practices, but also promoted the emergence of the application guidance or references of different materials and corresponding crafts. (Table 0-2) Table 0-2 Guidance or References about ‘Material and Craft’ Literature

Author

Times

Content Summary

Constructing Aarchitecture

Andrea Deplazes

2005

Material - Module Includes Properties (Types), Design

Materials Processes

Construction, Techniques, Structure Types about Masonry,

Structures - a Handbook

Concrete, Wood, Steel, Insulation Materials and Glass

Materials For Design

Victoria Ballard

2006

Bell, Patrick Rand

Including Material General Introduction, History, Design Consideration, Types and Connecting Methods about Glass, Concrete, Wood, Metal and Plastic

Materiali per l’edilizia

Construction+Materiality

Carlo Amerio,

2009

Including Material Types, Properties, Applied Positions and

Giovanni

Crafts about: Stones, Ceramics, Plaster, Concrete, Metal,

Canavesio

Glass, Plastic, Wood and Painting

Lorraine Farrelly

2009

Including Material Histories, Context, Applications, Representative Architects and Cases about Masonry, Concrete, Wood, Glass, Steel anf Synthetic Materials

It can be seen from these literatures that the classification and crafts of many commonly used materials differ a lot in every country3: part of them focus on the description of the crafts in actual construction and structural systems, resembling the deepening and sublimation of the Material Science; others lay much emphasis on the cultural and artistic expression of the craft. As Pier Luigi Nervi said, ‘The selection and application of the material is another technical factor which strongly influences the artistic performance.’ Nowadays, with the tide of the Tectonic Culture, the material and craft is no longer simply regarded as a kind of techniques in construction, but has risen to a significant position which is be able to show the architectural order and even tell the stories about human, myths and fantasies4. █ STUDY PROBLEMS AND AIMS Based on these two architectural fields which have been greatly concerned in the recent years, a certain idea is raised: Is there any possibility to make a systematic study and analysis of the

represents the structure function, and becomes a structural symbol. 3 For example, in the Italian course textbook ‘ Materiali per l’edilizia ‘, Brick will be included in Ceramic Products and separated from Stone classification while Mortar is individually as a class of materials described in detail; However, in the US context of ‘Materials For Design ‘, there is nothing at all about Masonry. These differences are more or less affected by factors such as geography or history, like in the Italian tradition, there are various different crafts dealing with different stones while for the traditional North American continent where Masonry is relatively lacked, the local rich wood is more inclined to be used. Thus, the influence of these aspects is also taken into account in the respective classification of the previous and interventional materials in the following paper. 4 In 2004, at the meeting of Nanjing University on ‘Structure, Texture and Topography’, Mitchell Schwarzer elaborated on the three dimensions of the idea of Semper's construction. 10

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

materials and crafts in old building rehabilitations? Before studying further on this problem, a preliminary searching and collating about the related literatures is carried on firstly. By reading the literatures (mainly the thesis papers) in Table 0-3, it is found that, first of all, they all start from the material itself, but avoid to talk about or rarely talk about the craft; Secondly, for those target on the old building rehabilitations, most only focus on the interventional materials (less on the previous materials) and talk about the methods of space, configuration, technique and other aspects, the expressions or performance and strategic principles. Consequently, it always gives a full range of each aspect but tasteless, quoted and cited extensively but without continuity. The reason is that the study issue is too large, and there is no clear and definite study object. Table 0-3 Thesis Papers related with ‘Material and Craft in Old Building Rehabilitation’ Title

Times

Summary

Research on the Material Used IN

2006

Basic Knowledge of Materials, Value and Protection of Old Materials,

Renovation & Extension

Configuration Methods of New Materials and Techniques between Old and New Materials

Impression Research on Modern

2009

material in Old Building Renovation

General Introduction of Modern materials, Preservation and Reuse of Old Materials、Intervention and Application of Modern Materials, Expressive Characters, Application Positions and Strategies of Modern Materials

Original and Creative Expressions of

2013

Materials in Old Building Renovation

Authenticity and Complexity of Material Design, Expression on Material Techniques and Expression on Subjective Experience

under Scope of Tectonics Research on the Application of metal materials in Renovation of Old

2014

Historical Development and Theory of Metal, Application Method, Principles on Different Levels, Application Tendency and Classic Cases

Buildings

Therefore, in order to discuss clearer and ordered in the following, the common concerned object and the coral intersection in both fields5 --- ‘Diachronic Interface’6 is selected as the starting point and the foothold of all the study content in this thesis. Subsequently, the thesis with the title of ‘Material and Craft Study of Diachronic Interface in Old Building Rehabilitation’ will develop and discourse upon the four specific problems as follows: (1) What is the existing (previous) material and craft of the old building? Why does it need to be linked with interventional (new) materials? (2) What material can be used for the diachronic interface? What factors will affect the selection? (3) How does the interventional material link with the previous one? What are the special crafts for a specific situation? (4) What are the design methods for the diachronic interface in terms of the material and craft? And how can they guide a real project? Through answering this series of simple questions, I hope that it will not only resolve my own doubts from personal interests but also provide some subtle but positive significance to the domestic and international research in this field: 5

In ‘Tell-the-Tale Detail’, Marco Frascari argued that it is the detail combines the material with space meaningfully. So the construction of the detail (e.g. diachronic interface), is the inevitable path to melt the material and craft into the building in order to create a magnificent space. 6 ‘Diachronic Interface’ is a combined word created by the author, but what it actually means is a familiar object and issue which will be extensively explained in the next section. 11

INTRODUCTION

In terms of theoretical aspects, provide a new link between the old building rehabilitation and the material and craft, supply the loss of the new and old relationships on the specific position and tectonic extent (which has recently been concentrated most on the historical context, space skills and aesthetic form) and provide a partial reference for the comprehensive study of the diachronic interface. In practice, it can also provide some specific and practical design reference and guidance for the material selection and craft techniques of diachronic interfaces in more and more old building rehabilitations. █ STUDY RANGE AND DEFINITIONS ● STUDY RANGE Although in the previous section the focus of this thesis and the main problems have been initially pointed out and clarified, there is still a big trouble to classify or analyze quantities of practical examples and cases systematically due to various objective factors affected; furthermore, because of space and time limitations subjectively, I hope that the thesis will be concentrated on a certain region during a specific period in order to elaborate fully and deeply. As a result, the study range of this thesis is fixed on the rehabilitation cases in Western Europe after the 1930s, in which the following paragraphs give the corresponding description of the two restrictions, "Western Europe" and "the 1930s". Western Europe, as one of the important birthplaces of European culture, not only enjoys a long history, but also retains the most abundant and diverse old cities and ancient buildings7. In addition, from the Roman period till now, basically during every cultural period there were the literatures on the building construction to be passed on for the future generations, thus forming a relatively complete the development system and context of the architecture. Therefore, Western Europe where enjoys thousands of years of civilization, provides a fertile soil and cultural support for the old building rehabilitation. (Figure 0-1) While about the determination of the starting year ‘the 1930s’, is primarily based on the following reasons: (1) As a whole, according to the development of the old building rehabilitation outlined in the previous section, the programmatic document ‘The Athens Charter’, developed by Congrès Internationaux d’Architecture Moderne (CIAM) in August 1933, for the first time put ‘Legacy of Historic’(related to the old buildings) on the international agenda. Although there had been already many restoration theories from different prominent experts, such as the stylisitic restoration from the French architect Violet-Le-Duc, the historical romantic protection theory from the British writer and artist John Ruskin, and the value theory of historic buildings from the Austrian art historian Alois Riegl, the real principles and guidance on the old building protection and rehabilitation which have been widely accepted and followed by countries nowadays, in fact started from this Charter which inherited the idea of the Italian scientific restoration, ’There should be differences in styles and material selections between the Old and New; All the restoration work

7

The concept of Western Europe mentioned here is not the usual one from the division of climate or geography but on the architectural extent, which can be also found in the book ‘Architectural Conservation in Europe and the Americas’. 12

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

should be documented and marked on situ to reflect the differences.’8 (2) From a local point of view, there were two important regulations about the old buildings promulgated in Italy, the "Italian Charter" and the first set of standards for the management of the old building restoration during the Mussolini Fascist regime in 1932 and 1938 respectively; While in Spain and Portugal which have less link with the other western countries due to the long-term dictatorships, the governments also promulgated the policies about the reuse and transformation of historic buildings from the 1930s, such as the Paradores (state-owned hotel system) in Spain and the Pousada (hotel system) in Portugal, which are the earliest examples of old building reuse. (3) In addition, in terms of the development of materials technology, the 1930s also has an epic breakthrough because of the birth of plastic – the discovery of PVC and VCM and the corresponding applications to new insulation materials and semi-permeable membrane materials which greatly improve the building performance and modeling methods. From this point, the basic classification of materials to be used in current old building rehabilitations is completely formed.

Figure 0-1: Definite Range of West Europe on Architectural extent

Although this time node does not completely correspond to the modern ideas of the old building rehabilitation in all the countries of Western Europe, I still hope that through this division of the time, not only the study will be more effective in searching of the information, but also make some efforts to the reference work on the developing history of old building rehabilitations in Western Europe. ● CERTAIN DEFINITIONS (1) Old Building At the beginning of this chapter, the definition of the old building has been identified: that is, any legacy individual building or building complex with a certain history and value, in which the age 8

This is quoted from ‘Architectural Conservation in Europe and the Americas’, 2011. 13

INTRODUCTION 9

of the building is generally more than half a century namely 50 years old , and the so-called value includes four categories: the function, art, historical archeology and tourism appreciation10. (2) Rehabilitation ‘Rehabilitation’, compared with ‘Conservation’ and ‘Restoration’ of the ‘Historic Buildings’, is much broader. Firstly, because the object is ‘old building’, those actions like ‘Demolition’, ‘Renovation’ and ‘Extension’ can be carried out on normal old buildings without huge significance. Then on the operation extent, it not only focuses on ‘Preserve the Physical Origins’ which is underlined through the maintenance of structure and decorations, but also pays much attention to ‘Inherited Relation between Old and New’ which is motivated by space ‘Reuse’ and function ‘Improvement’ and regards the material and craft as the study key point which expands the ‘Restoration’ only with original materials and crafts to the ‘Reconstruction’ with more extensive materials and crafts. Table 0-4 Distinguish between Different Terms Term

Definition

Reference

Conservation

All the work in order to understand the history and meaning of

1994 the World Heritage Convention;

cultural heritage, to ensure the material safety and, if

2008 ICOM-CC

necessary, to repair and improve all cultural heritage; All the measures and actions aimed at protecting the tangible cultural heritage and ensuring that it is presented to future generations, respecting the cultural heritage itself Preservation/

Similar with conservation, interchangeable, more focused on

1994 the World Heritage Convention;

Protection

the specific operation; Maintain the texture of the existing site

1999 ICOMOS Australia Burra Charter;

and slow down the deterioration; Reduce the chemical and

1996 AIC

physical deterioration of cultural heritage and prevent the loss of information, the primary goal is to extend the life of it Maintenance

Unlike Restoration, the continuous protection of the

1999 Australia Burra Charter

environmental texture Restoration

Its purpose is to protect and reveal the aesthetic and historic

1964 Venice Charter;

value of the monuments based on the original real documents;

1999 Australia Burra Charter;

Recovering to a earlier state through removing attachments or

2008 International Museum

reconstructing existing elements without using new materials;

Preservation Committee

All the measures applied directly to the object are intended to promote awareness and use of it and based on the respect for the previous materials Reconstruction

The site is restored to a known earlier state by adding new

1999 Australia Burra Charter;

material in the texture to make difference Rehabilitation

The measures taken In order to extend the life or due to

1982 National Research Council of

economic considerations, more adaptable changes rather than

Canada;

protection, but still retain most original features of the building;

1983 Canadian Heritage Committee

Similar to Renovation, especially for existing buildings 9

According to ‘Historic Buildings and Monuments Act’ promulgated by the Dutch government, any building that has existed longer than 50 years can be included in the protection list. 10 These categories were proposed by Professor Canon Raymond Lemaire of University of Leuven in 1938 which was based on the Riegl’s value theory and embodied in the article ‘Restoration of Ancient Monuments’. 14

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION Term

Definition

Reference

Renovation/

In practice, may include restoration, reconstruction and other

1982 Canadian National Research

Refurbishment

acts, relatively expensive and extensive measures;

Committee

A term that describes different levels of interventions, including

1983 Canadian Heritage Committee

reconstruction, reuse and restoration, is an improvement over

2008 Design Guidelines for Department

existing buildings or the surrounding environment;

of Defense Historic Buildings and

Modernization to old buildings or historic buildings, may result

Districts

in inappropriate alteration or removal of important features and details Intervention

Except for Demolishment and Damage, any acts to alter any

Standards and Guidelines for the

element on historical site physically

Conservation of Historic Places in Canada

Transformation

Functional Transition of existing buildings

Merriam-Webster

Adjusting process in order to meet new needs or environment

Merriam-Webster

/ Conversion Adaptation

change of existing buildings

However, there are still other similar terms in English, as are shown in Table 0-4. Renovation’ (‘Refurbishment’) is more concerned with modernization, with a tendency to completely renew, lack the value protection of the old building; ‘Transformation’ (‘Conversion’) lays more emphasis on function alteration with less relation to construction; ‘Adaptation’ appears with the sustainable development, pay more attention to the applications of green energy-saving technology; ‘Intervention’ is more widely defined and used, which can’t directly reflect a kind of tendency to diachronic interface. As a consequence, finally I decided to use ‘Rehabilitation’ as the corresponding English word in the thesis, despite in the existing context, it is more inclined to be used for historical buildings, but its connotation of the inheritance and continuation between ‘Old and New’ is most consistent with the attitude which this thesis would like to convey. (3) Diachronic Interface11 In ‘Architecture Reborn: The Conversion and Reconstruction of Old Buildings’, Powell used ‘the interface of old and new’ to describe the object which appears in the old building rehabilitations. However, in my opinion, it is not the best appellation for it. Although the word ‘interface’ is more accurate than the word ‘joint’ or ‘junction’ for the actual study object, due to different shapes and forms of it, such as a point, a face, or a body, the word ‘old and new’ is still a little bit lengthy and can’t accurately reflect the concept of "convergence" among more materials. Thus, the word ‘diachronic’ is selected as the adjective of the object. More specifically, if from the material and craft point of view, any specific position of the building where the materials from different historic periods coexist and physically connect through certain craft, can be called the diachronic interface. Therefore, the diachronic interface mainly has two levels of connotation: one is diachronic continuity and the other is synchronic connection. The so-called diachronic continuity is more 11

Diachrony is firstly utilized by the prominent linguist Ferdinand de Saussure in the study of language. From his point of view, diachrony and synchrony are the two main concepts and methods for study. The former is based on a general context in different periods of time and dynamic, while the latter is concentrated on the still object in a certain space at a definite time. 15

INTRODUCTION

from a philosophy point of view and much abstract. For example, in the main hall of the Cathedral of Girona, a series of historical reconstruction models are presented (Figure 0-2). From Roman Tempio with the H shape enclosed stoa and narrow stairs in the 2th century, to Romanesque Basilica with the Latin cross layout and diagonal towers in the Middle Age, then to Christian Church with a rigorous facade of geometric proportion, upper Lantern and flying buttress during Renaissance, final to Baroque Cathedral with the large scale staircase, facade and bell tower. Although different styles prevailed at each stage, at the glance of the photo in Figure 0-3 of the South Entrance, a historical continuation and unity can still be sensed through the similar material use and innovative craft approach. It is quite common in Western Europe that this kind of situation appears all the time in the cultural evolution, no matter in which monastery, palace or cathedral we are wandering, traces and imprints left through years are still able to be read from different layers, just like a long scroll spreading out in front of eyes, and making the imagination to fly with them. This kind of connotation that can evoke people's perception of history makes the old building no longer just the physical entity of the space, but the spiritual carrier full of cultural appeals.

Figure 0-2: Reconstruction Models of the Cathedral of Girona in Different Times

And the synchronic connection, is more focused on the interpretation of "interface". Compared to the diachronic continuation on the macroscopic level, the synchronic connection is on the more practical level of construction, which is based on the function and requirements of the old building rehabilitation. As a result, each diachronic interface has its own characters and properties, which will be further discussed in the following.

Figure 0-3: South Entrance of the Cathedral of Girona 16

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

█ THESIS OUTLINE AND METHODOLOGY

17

CHAPTER 01 EXISTING MATERIALS AND CRAFTS

CHAPTER 1 EXISTING MATERIALS AND CRAFTS

█ 1.1 GENERAL CATEGORIES Viollet-le-Duc once said, ”If artists today work for the living, they must live with the dead. Because only they can teach them.”12 To clarify what type of materials will be used and what kind of crafts will be applied in the old building rehabilitation, the first thing need to know is the existing materials and the corresponding crafts. It is not only the retrospect of the previous history of the old building and the investigation of the existing situation, but also the necessary basis which establishes the understanding and linkage of the old and new relationship. ●1.1.1 STRUCTURAL MATERIALS AND CRAFTS 1.1.1.1 Masonry As the oldest and most durable building material, masonry still retained on lots of old buildings and exudes a sense of dignity after time precipitation through various bonds and textures. The use of stone, due to its natural property, presents a rich state with the geography. For example, the most common historical relics left from ancient Greek&Roman Times have already contained the stones in the latter buildings: from the white pentelic marble in the Parthenon Temple on Acropolis to the calcarenite limestone in the Agrigento Tempio in Sicily; from the pale pink travertine of Verona Amphitheatre to the dark gray lava stone and basalt of Catania Amphitheatre; from the dark gray Guadarrama granite of the ancient Roman Aqueduct in the old town of Segovia to the yellow-white sandstone of the Pont du Gard in suburb of Nimes. (Figure 1-1) The bricks, as described by Vitruvius in the second book of The Ten Books on Architecture, should be certain lightweight but impermeable material which is made of chalk (or red clay) after dried or baked. According to the soil composition, there will be differences in hardness and color. However, with the mature firing process, nowadays most of the brick on the old buildings are baked clay brick. Therefore, starting from the physical properties of the two materials, they are homologous, and have a good load-bearing compression performance. As a result, they are particularly suitable as a vertical structural component in a building, such as a pillar, or a wall. With the functional requirements of the larger span and covering, there gradually appeared the perfect structural elements such as the arch and dome through wood formwork.

Figure 1-1: Different kinds of Stones used in Different Ancient Buildings

12

From the Preface of Architecture and The Historical Imagination written by Martin Bressani (2014) 20

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

(1) Columns --- From Nature Imitation to Property Presentation The earliest appearance of the masonry derived from the column-beam structural system of wood and primitive sheds, the main crafts are based on those of wood, such as the use of hidden falcons and metal connections (Figure 1-2, a). In addition, the worship of nature is also shown through the column surface which was chiseled with vertical groove, spiral pattern and other figures. But with the more and more constructions of masonry buildings, the increasing lack of large-scale stones and the increasing height of structures, more and more monolithic large columns are beginning to be made from small pieces of stones, such as the Gothic octagonal column of Santa Maria del Mar in Barcelona, which is actually composed with 1 square stone in the centre surrounded by 4 hexagonal stones for each course while there is a 45-degree rotation for each course to be bonded tightly and make rich texture (Figure 1-2, b). This kind of craft also leaded to the bond development of masonry walls in the following periods.

a

b

Figure 1-2: Comparison between the Greek Column and the Gothic Column

(2) Walls --- From Solid Opus to Laminate Bonds The masonry wall is very common because of its good envelope insulation and space separation, which is used in most public buildings and private homes. After the combination of brick, gravel and mortar, it forms a richer surface and structural texture (Table 1-1). From solid opus that purely relies on the stone cutting and joint close, to the brick block adhesion with mortar, and then to the mixed masonry with facial bricks and inner concrete, brick and stone are gradually unified in the masonry process, and are collectively called Ashlar Masonry. Table 1-1 Solid Opus in Ancient Times Craft

Explanation and Application

Opus siliceum

Huge polygonal stone blocks closely jointed without mortar Sustain quite large side thrust; Generally used as foundations

Opus quadratum

Regular square stone blocks with the same heights bonded course by course without mortar; Mainly used for early stone structures

21

Sketch

CHAPTER 1 EXISTING MATERIALS AND CRAFTS Craft

Explanation and Application

Opus

rubble concrete as filling for the wall construction cast with wood

caementicium13

moulds;

Sketch

Only exists during Roman Times because of the special raw material---pozollana;

Opus incertum

Irregular stone or travertine block bonded with mortar as the cover filled with concrete; Rough and primitive appearance but strong and solid; Mainly for the early stone structures and latter vernacular or low-cost buildings;

Opus reticulatum

Pyramidal Stones with the same size bonded on the surface at 45 degree incline with mortar and filled with concrete; Beautiful appearance but with low capacity;

Opus lateritium

Solid brick bonding or surface brick bonding filled with concrete;

(testaceum)

Mainly used in Roman Times, later the filling was changed into rubble and the surface was linked with metal anchorage which was widely used;

Opus mixtum

The surface is bonded with both bricks and stones filled with concrete inside; Combine two opus (Reticulatum and Lateritium),which is quite similar with the latter craft of stone covered corner walls;

Opus vittatum

Stones or bricks with the same height bonded horizontally in each course while each course with different height and filled with concrete inside;

Opus spicatum

Stone or brick slabs bonded at a inclined 45 degrees in each vertical list while each list in opposite direction with the adjacent one, which forms a herringbone structure; Generally used in the pavements or decorations;

Resources from: http://www.romanaqueducts.info /picturedictionary

13

In Ancient Engineers’ Inventions: Precursors of the Present, Opus caementicium is explained as a “concrete work”, namely the binder from “pozzolana”, a kind of volcano ash, the property of which is quite similar with the Portland cement in the modern concrete. 22

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

Also with the increase height of the masonry wall, the construction of upper floors is mainly relied on the additional wooden scaffolding. Under ordinary circumstances, Putlog will be inserted into the wall which has already been built, or with the vertical bars supported by the ground, or with the independent triangular truss supported in the wall to complete the construction. As a consequence, the holes for wood putlog during the construction will be left on the wall and become the most obvious imprint on the façade which manifests the craft of masonry at that time (Figure 1-3, a).

a

b

Figure 1-3: Putlog for Masonry Wall Construction and Early Standard Brick/Stone Block (G.R.II.Wright. Ancient Building Technology: Volume 3 Construction, 2009)

With the rise and development of Material Science in the 17th century, the knowledge expansion of the physical properties of structural materials accelerated the further standardization of the processing of masonry materials. This kind of masonry blocks are mostly rectangular cubes and can be divided into three different faces (bed, edge, end) and bonded course by course in two directions (stretcher or header) (Figure 1-3, b). Through the brick rotation of each course, a rich and interesting façade is formed with a kind of weaving pattern, such as the cases in Table 1-2. Table 1-2 The Bonding Types and Characters of Standard Blocks

Stretcher Bond Early surface wall

Header Bond Early solid wall

filled with rubble;

English Bond Early to the 17

th

Flemish Bond Start from the 17

English Cross Bond th

Improvement of

century solid wall

century solid wall

English Bond, solid

Monotonous; Good

Monotonous;High

Bond change course

Bond change in one

Bond change course

tension capacity;

Compression

by course

course; Good interlock

by course and

more for double-layer

Capacity; More for

performance

stretcher course also

wall

wall footing

change;Strength better than English Bond

Resources from: www.theheritagedirectory.co.uk

(3) Vaults --- The Continuous Exploration on Material Limits "What do you want to be?" The brick answered, "I want to be an arch." So the birth of the Roman 23

CHAPTER 1 EXISTING MATERIALS AND CRAFTS

arches is not accidental, but based on the architect's years of practical experience and the natural invention and creation due to the material technology at that time. Through the wooden frame support (the ancients are familiar with the skills), the stone for arch which is pre-chiseled will be laid one by one from both sides of the wall up to the middle, and ultimately form the arch. According to different spans of the arch, there are also different combinations for the corresponding wooden frames (Figure 1-4).

Figure 1-4: Wooden Frames for Constructing Arches with Different Spans (G.R.II.Wright. Ancient Building Technology: Volume 3 Construction, 2009)

With the development of the space depth and the coverage demand, then the barrel vault, crossing vault (groin vault) and dome formed as the roof of large space with masonry. From the specific craft point of view, they basically continued the construction of the arch: firstly build a wooden structure with the form, and then bond stones or bricks piece by piece attached to it. And because of the use of concrete in the Roman period, the original solid masonry can be transformed into a craft that several arches can be built as skeleton and template to fill with concrete, which also laid the foundation for rib vault frame system afterwards (Figure 1-5). For the dome, because it is not simply two-dimensional surface, the construction methods of wooden frame and masonry seem to be much more complex. For example, for the greatest temple Pantheon in ancient Rome, there exist many different speculations of the construction craft (Figure 1-6).

Figure 1-5: Craft Transition from Solid Barrel Vault to Rib Vault Frame (G.R.II.Wright. Ancient Building Technology: Volume 3 Construction, 2009)

Similarly, with the increase in the height of the building, vaults or domes which were only for single-floor buildings were unable to meet the multi-storey masonry structure’s need of the morphological requirements. Although the problem can be easily solved with wooden beams and 24

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

floors, the masonry floor is still the only option for those buildings with a higher demand of fire resistance or a humid environment. Therefore, in order to more effectively meet the use and to solve the weak of masonry on bending and shear capacity, brick floor structure with flat arch came into being. The most representative one is Catalan vault14 (Timbrel Vault), which has thousands of years of history and is still being used widely in this region. Since it is not loaded as the ordinary vault which transfers compression load between blocks, but through the use of the adhesion force of mortar between multi-layer of masonry, an entire laminate shell structure is formed to bearing the force as a whole. As a result, it not only reduces the vault thickness, weight and thrust on both of the side walls, but also makes the bearing capacity of the entire vault be further improved. At the same time in the construction aspect, due to the self-bearing of the structure, the original complex wooden frame can be reduced or even completely abandoned, and replaced by some slim cables as a supporting frame, which greatly saves construction costs and labor (Figure 1-7).

Figure 1-6: Three Different Speculations on Construction Craft of Pantheon15 (G.R.II.Wright. Ancient Building Technology: Volume 3 Construction, 2009)

Figure 1-7: Construction Craft of Catalan Vault (Tradition and Moodernity of Catalan Vaults: Historical and Structural Analysis, 2012) 14

Catalan Vault was firstly discovered in the constructions of Assyria and Sumerians in Mesopotamia and then passed on to Spain during Byzantine, to Italy in the Middle Age, which was affected both by Opus caementicium and Islamic brickwork. 15 The first one on the left shows Viollet-le –Duc’s hypothetical scheme of the wood frame for flying centering which was supported on the top of the circular wall while in the middle shows the wood frame conceived by Rakob which with the central tower; Furthermore in the right sketch, Durm assumed the dome was composed with several small brick arches superimposed together. 25

CHAPTER 1 EXISTING MATERIALS AND CRAFTS

1.1.1.2 Reinforced Concrete Casting Compared with the "sentimental" masonry, though the development of reinforced concrete casting is relatively short, not only was the problem of limited load capacity of masonry materials solved due to the internal structure (steel bars or metal components) as reinforcement, but also a close connection with the earth was maintained through the external pouring of the concrete, from which a primitive and pure atmosphere can be highlighted through the traces left behind during the construction process. From material point of view, modern concrete uses Portland Cement (Invented by Aspdin in 1824,) or lime mortar (with a certain ductility, generally used for early solid concrete pouring), mixed with aggregates and water stirred into a mixture, then poured into a pre-set template for the vibrating compaction, and dismantled after hardening. Though the original mixture of the concrete may have slight difference in appearance due to the choice of different aggregates, a richer texture can be obtained through different casting template selection and surface treatment (Table 1-3). Table 1-3 Main Textures of Traditional Concrete Surface

smooth:

plank-pattern:

relief:

fair-faced:

Metal Template

Wood board Template

Other Material Textures

Set Rod and Bolts

polished:

brushed:

chiseled:

washed:

By Machine

By Brushes

By Graver

By Water Jet

Resources from:http://www.tmbelement.ee/en/concrete-surfaces/tiled-surfaces

And the reinforcement components hidden inside, normally will use cast iron, wrought iron, steel or other similar materials buried before casting. And their specific forms, with the continuous innovation of structural mechanics theory and material science, have been developing towards slender and more intensive force distribution (Figure 1-8).

Figure 1-8: Different Types of Internal Reinforcement Elements (Radfords Cyclopedia of Construction Vol 6 Concrete Construction to Building Construction) 26

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

(1) Columns and Walls --- From Masonry Imitation to Property Expression Since the concrete itself can meet the mechanical properties of the wall pressure, the internal reinforcement only needs to provide a tight connection with the other members (longitudinal bars) and avoid the expansion of concrete at lateral sides (stirrups). In the early reinforced concrete structures, in order to maintain the original classical architectural style, a variety of ways were applied to hide the primitive surface of concrete. For example, in the first reinforced concrete building --- a Paris residential designed by Francois Coignet in1853, the external walls are completely covered with plaster and achieve the appearance of unity with other masonry buildings through a variety of stucco decorations. In addition, many public buildings built in reinforced concrete were also covered with masonry materials to maintain the traditional aesthetic taste (Figure 1-9).

Figure 1-9: Technical Drawings of the Paris Residential designed by Coignet (https://aehistory.wordpress.com/1853/10/05/1853-first-reinforced-concrete/)

However, with the rise of the Modernism and its advocacy of pure functional space, more and more concrete walls began to get rid of the fate as hidden structures, and with the vigorous development of industrial production, more tend to highlight its own material properties. For example, in many industrial buildings with column-beam reinforced concrete structure, the more effective force transfer path between the columns and the beams is set up by means of the section increase at the top of the column. In some public buildings, the original mark of the construction process is left on the structure surface through different types of template for casting concrete. (2) Slabs and Beams --- Adaption according to Reasonable Load Analysis and Practice Slabs and beams, are the most extensive reinforced concrete structural components used in the old buildings. Because it is much easier to achieve the level of horizontal coverage and span which masonry can’t get while compared with the wood, it has a more lasting performance and uniform force distribution, it has become the most common slab material to be used in old buildings since the second half of the 19th century. Therefore, the exploration about the reinforcements is very abundant, which can be classified as the following two categories (Figure 1-10): (1) Iron or Steel girder coated with concrete, the main body of this craft is iron or steel, which 27

CHAPTER 1 EXISTING MATERIALS AND CRAFTS

covers with concrete at its peripheral space to protect from decay. According to the concrete casting forms can also be divided into three different types: (a) the arched floor similar to the masonry structure, (b) the ordinary beam-slab frame and (c) the flat floor respected by modernism; (2) Concrete inserted with horizontal and vertical reinforcements, concrete-based floor needs a greater thickness, through setting a number of reinforcements at the bottom of the beam and slab to provide the resistance to the tensile stress of the section produced by the bending moment. And for the larger span beam, some fasteners can also be set at a certain interval vertical or oblique to the cross-section to resist the shear force. In practice, the general cases are (d) the main-girder floors and (e) grid-beam floor.

Figure 1-10: Different Types of Reinforced Concrete Floors (Radfords Cyclopedia of Construction Vol 6 Concrete Construction to Building Construction)

1.1.1.3 Iron and Steel Anchorage From the material point of view, the iron can be mainly divided into cast iron and wrought iron, cast iron is formed by mold pouring, with good compression performance but relatively poor toughness which is generally used as a structural column; while the wrought iron is formed by hammering in fire, with a better ductility and variable form but the weaker strength, which is more in line with the requirements of the structural beam (although sometimes also can be used as a structural column). With the steel mass production from the late 19th century, they were both replaced. It is because steel as a new alloy material, is not only more durable, but also can form a variety of structural elements through the different carbon ratio and craft methods. However, in terms of the anchorage crafts, they can be basically divided into the following categories: riveted, welded and bolted (Figure 1-11). Although these crafts are unique, but in general, the rivet anchorage with rivets and connecting plate is still the most widely used craft on the old buildings for the time being, with an intuitive mechanical expression and the imprint of the construction process. 28

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

Figure 1-11: Different Types of Anchorage (Riveted Connections in Historical Metal Structures (1840-1940), 2014)

(1) Columns and Beams --- Frame Structure from “Hidden” to “Exposed” According to "Structure and Architecture" written by the British scholar Angus J. McDonald, the relationship between architecture and structure can be divided into no more than 2 categories and 6 types16. The "hidden" or "exposed" structural problems involved are more epoch-making and enlightening to iron and steel than the traditional masonry because there are a total change of the architecture from space to structure, material to craft. First of all, conservatives and most of the general public were not satisfied with the over-new appearance and the uncertainty of carrying capacity of iron and steel. Thus, in many important monuments or large public buildings at that time, more steel components are deliberately hidden inside the masonry wall, which is called "structure ignored". Such buildings as the reading room in the atrium dome of the British Museum and the Union Bank of Scotland, nothing related to iron or steel can be traced from the appearance and the actual structural crafts can be discovered only through the historical data (Figure 1-12).

Figure 1-12: Comparison of the Appearances between Constructing and Finishing (http://www.britishmuseum.org/ and http://www.mediastorehouse.com/)

While other pioneers who focused on the historical style and architectural protection at that time, hope to achieve a unity of new material and the old style by imitating the original shape of the masonry structure and weakening the iron or steel's own material characteristics, which can be described as "structure as ornament ". Such as the Bibliothèque Sainte-Geneviève designed by Henry Labrouste, in the middle of the two-storey reading room, a row of iron pillars lightly growing up from the ground and separated respectively at the top to connect the beautifully decorated hollow wrought iron arch from both sides of the wall. Although the size of the material itself forms a certain contrast to the original thick wall, a style of consistency is still set up with the tradition through the amplification of the column base, the grooving on the column, the Ionic decorations of the capital and the scroll texture of the arch, which brings a familiar classical 16

The two categories are “structure hidden from view” and “structure exposed” which can be divided into six types: “ornamentation of structure”, “structure as ornament”, “structure as architecture”, “structure as form generator”, “structure accepted”, “structure ignored”. 29

CHAPTER 1 EXISTING MATERIALS AND CRAFTS

feelings to the cold and boring space (Figure 1-13).

Figure 1-13: Iron Details of the Arch in the Bibliothèque Sainte-Geneviève (https://www.pinterest.com/)

However with more and more urgent need for large space due to the social production and population growth and the further pursuit of material authenticity in the architectural field, slender iron and steel columns and beams began to completely abandon the traditional decoration, and fully performed their properties through more reasonable and suitable crafts. In many industrial buildings, the plain iron or steel beams and columns transfer the vertical loads reasonably and express the material accuracy and excellent craft through the optimized connections, which is called "structure as architecture ". For example, in the La Galerie des Machines designed by Contamin & Dutert, large-span arched iron and steel trusses are articulated at the top and ground with hinge, and are securely connected through the secondary trusses to form a new frame building expressing the structural rational (Figure1-14).

Figure 1-14: Iron Details of the Trusses in the La Galerie des Machines (https://www.pinterest.com/)

1.1.1.4 Wood Frame Joint According to Laugier, the building originated from the primitive shed, timber is the first material applied to of human house construction. There are abundant natural wood resources in nature, on one hand providing a variety of different sizes of woods for the construction, such as long trunk can be directly used as a building frame component; on the other hand also bringing a lot of 30

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

specific problems to the material selection and the processing technology. Just like Vitruvius said in Section Timber of "The Ten Books on Architecture", corresponding to different wood species and their own properties and characteristics, there are specific use and processing methods. Combined with some references on the introduction and classification of wood, basically the use of wood in the old buildings in Western Europe can be categorized as follows: Table 1-4 Main Species of Traditional Natural Wood in Western Europe Name

Genera

Properties

Instruction for Use

Cedar

Pinaceae

From light pinkish to reddish brown,

Veneer, plywood, cabinetry,

cork wood

Fir

Cypress

darken with age;

musical instruments,

Straight or shallowly interlocked

(flamenco and classical

grain; Medium texture; Distinct odor,

guitars), humidors, and

good rot resisitance and durability

boatbuilding.

Pinaceae

From white to reddish brown;

Temporary Structure;

cork wood

Straight grain with uniform

Generally easy to work with

medium-coarse texture;

both hand

No odor, low rot resistance;

and machine tools; Glues,

Relatively stiff, light and flammable

stains, and finishes well.

Cupressaceae

Light yellowish brown; Staight grain

Exterior construction, docks,

cork wood

and medium to coarse texture;

interior trim, and veneer.; Work

Distinct sour odor and durable;

with both hand and machines;

Easy to bend in water

Glues, stains, and finishes well but not steam

Elm

Aspen

Oak

Ulmaceae

From light to medium reddish brown;

Structure and veneer;

cork wood

Interlocked grain and coarse uneven

Glues, stains, finishes and

texture; Strong unpleasant smell

steam bending well; ; Holds

when green and little odor after dried;

nails and screws; Work with

Non-durable to rot resistance

both hand and machines

Salicaceae

Heartwood is light brown while

Structure and veneer;

cork wood

sapwood is fron pale yellow to white;

Work with both hand and

Straight grain with uniform medium

machines; Poor nail-holding

texture; No odor and non-durable to

capability; Glues and finishes

rot resistance; Stiff and relatively light

well; Easy to bend when drying

Cupuliferae

Heartwood from light to medium

Interior trim, floors and

hard wood

brown; Straight grain with coarse

cabinets; Work with both hand

uneven texture; Appealing smell;

and machines but react with

Durable to rot resistance and

iron when wet; Glues, stains,

Humidity; Stiff

finishes and steam-bending

Photo

Spainish Cedar

European Silver Fir

Cypress

English Elm

European Aspen

English Oak

well Beech

Cupuliferae

Typically pale cream color and

Timber frame, floors, cabinets

hard wood

golden after steam-slicing; Straight

and non-decorative wood;

grain with a fine to medium uniform

Work with both hand and

texture; No odor and Non-durable to

machines; Glues, finishes and

rot resistance; Sitff

steam-bending well

31

European Beech

CHAPTER 1 EXISTING MATERIALS AND CRAFTS Name

Genera

Properties

Instruction for Use

Birch

Betulaceae

Heartwood is light reddish brown

Interior trims, cabinets and

hard wood

while spawood is nearly white;

only indoor uses; Work with

Generally straight or slightly wavy

both hand and machines but

grain with fine even texture;

wild grain better with hand;

No odor and non-durable to rot

Glues, stains and finishes well

Photo

Silver Birch

resistance Alder

Ash

Betulaceae

From light tan to reddish brown and

Cabinets and foundation

hard wood

darken and redden with age; Straight

supporting piles; Work with

fine even grain with closed pores;

both hand and machines,

No odor and non-durable to rot

especially sands; Glues, stains

resistance

and finishes well

Oleaceae

Heartwood is from light to medium

Floors, Handles and joint nails;

hard wood

brown with darker streaks; Straight

Work with both hand and

regular grain with medium to coarse

machines; Glues, finishes and

texture similar to oak; Moderately

steam-bending well

unpleasant smell; Non-durable to rot

European Alder

European Ash

resistance; Good strength and ductility, anti-seismic Resources from: http://www.wood-database.com

In terms of material joints, wood lashing and lumber lapping (lodgements and engagements) were the most common crafts for building during the ancient times; Afterwards, the crafts about metal nail and glue were invented and developed which more firmly connected the wood elements together as a whole and loading uniformly (Figure 1-15). Among them, the most widely used two are lapping and nailing in the existing old buildings. And furthermore, as a craft without the use of any additional material, the lapping joint, is most abundant, which includes halved joints, tenon joints, oblique joints and tongue-and-groove joints (Figure 1-16).

Figure 1-15: Different Types of Wood Joints: (a) Lashing (b) Lapping (c) Nailing (d) Glue (http://www.basiccarpentrytechniques.com/)

Figure 1-16: Different Types of Lapping Joints: (a) Halved (b) Tenon (c) Oblique (d) Tongue-and-groove (Wood and Wood Joints: Building Traditions of Europe, Japan and China, 2011)

32

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

Therefore, as the only natural material with good tensile properties, the wood has become the most common elements for roof structure in the old buildings, and had been widely used until the early 19th century with the rise of iron and steel materials. To talk about the early roof structure of the wood buildings, there are two main types: bearing beams and trusses, as shown in Figure 1-17. The former one, which the roof load is carried by the purlins and passed to the lower beams and columns, is more suitable for small rooms due to the limited bending capacity of the wood at the beginning and gradually developed into the internal wooden floor structures of multi-storey buildings which can be found in many existing old houses; and the latter one, which the roof load is carried by the stable triangular trusses with the upper diagonal elements in pressure, horizontal element in tension and the vertical element in support, can span larger spaces and develop into various forms for different scales and slopes of roofs according to corresponding transformations of the joints and become the main type of the wood roof structure in Western Europe afterwards.

Figure 1-17: Main Types of Wood Roof Structure in Classical Times (G.R.II.Wright. Ancient Building Technology: Volume 3 Construction, 2009)

(1) Wood Roof Frame --- Optimized Structure from Heaviness to Lightness17 According to the analysis of Klaus Zwerger, the wooden roofing structure in Europe is mainly the truss post (spar roof), namely the truss structure mentioned above. For the different spans and slopes, there are three main simple types (Figure 1-18): basic triangular truss, a version with vertical queen posts and a version with inclined queen struts. The first is suitable for slow roofs, such as many ordinary residential buildings in southern Europe, the stability of which can be guaranteed by adding more internal elements; While the latter two are more suitable for steep roofs with attics, such as the towering roofs of many Gothic churches and coping with Multi-storey attics by adding the numbers of the lower horizontal and elements. Due to the use of the continuous solid wood for load concentration need, the wooden roof frame presented a heavy image at this period.

Figure 1-18: Main Types of Wood Roof Truss in Europe (Wood and Wood Joints: Building Traditions of Europe, Japan and China, 2011) 17

Although in the development of the old wooden buildings, there are also log construction and column-and-beam construction, but due to the limited content here as well as less links with the following cases and project, here only the roof structure is discussed extensively. 33

CHAPTER 1 EXISTING MATERIALS AND CRAFTS

With the further development of carpentry crafts, not only were there some changes in the cross-section of the elements, such as the section of inclined queen posts reducing from top to bottom according to the load distributions (Figure 1-19, a), but also some new elements in different directions were added to reduce the size of a single wood overally, such as St Andrew's cross, secondary spars, longitudinal oblique tension rod and so on. Among them, the most prominent and optimized structure - suspended truss post, has solved the dual problem of the weight of the vertical element as well as the load on the lower horizontal rod. By placing the stabilizing pole on the upper inclined elements or the horizontal collars rather than the horizontal rod before, it not only produced a richer node form, but also brought out a much slimmer visual experience of the roof structure (Fig. 1-19, b).

Figure 1-19: Some Renovations about Wood Truss Elements (Wood and Wood Joints: Building Traditions of Europe, Japan and China, 2011)

Figure 1-20: Main Types of Composite Roof Truss in the 17th and 18th centuries (Notes On Building Construction: Roofs of Wood and Iron Combined)

In the 17th and 18th centuries, due to the introduction of iron and steel, the structure of the wood trusses became much lighter, and many elements in tension, such as horizontal rods or webs, were completely replaced; and at many joints of them rivets, bolts or straps were used, thus forming the most common and reserved composite roof structure nowadays (Figure 1-20). ●1.1.2 CLADDING MATERIALS AND CRAFTS 1.1.2.1 Plaster --- Abundant Surfaces As a synthetic building material, the history of plaster is as long as that of masonry, and the crafts of it are more complicated than those of any other old building material. Only through mixing available natural materials (lime, gypsum, stone, sand, water and etc.) together in certain way, a variety of distinctive decorative changes in texture are formed with the transformation of different combinations (Table 1-5). These traditional plastering crafts, or smearing layer by layer, or pouring separately, or stitch bonding, not only protected the original flat and boring surface of the structure durably, reduced the costs and weight, but also became the expression and manifests of the style of the times, religion emotions, aesthetic taste, status and even the geographical characteristics. 34

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

In addition, the plasticity of the plaster made it possible to obtain the traditional appearance advancing with the times through the adaptive transformation of the crafts in each development of the structural materials. Such as in the era of short of marble, the column which should be chiseled from a monolithic marble previously, would be produced through wrapping the bricks structure with artificial marble mortar (Scagliola) pasting on canvas to achieve the same surface texture; and in the era when iron and steel were gradually rising, the original stucco ceilings pasted with the wood supporting members, were then changed into wire stucco ceilings with wrought iron ribs screwed together with simple angle pieces to obtain the approximate engraving texture. Table 1-5 Main Traditional Plaster Crafts Name

Material and Explanation

Time and Regions

Features

Marmorino

Smear a layer of cocciopesto at the

Ancient Roman Times;

Both Interior and

base, then cover with the mixture

Italy and other Western

Exterior Walls;

of crushed marble and lime putty,

European countries

Different colors

finally chip evenly

th

th

from the 15 to 19

imitate stones;

century

Anti-Insects and

General View

water Scagliola

Multi-layer mixture composed of

Popular in Tuscany and

Both Interior and

selenite、glue and natural

Bavaria Regions during

Exterior Walls

th

pigments;Strip texture is made

the 16 and 17

from raw silk inserting or chiseling

centuries

th

Imitate rare

randomly on different layers Sgraffito

Cover Multi-layers of plasters in

and Columns;

stones In Italy and Germany th

Both Interior and

different colors on wet surface,

during the 15 and 16tj

Exterior Walls;

then scrub to present different

centuries; Art and Crafts

Decorative

layers, similar to frescoes;

Movement at the end of

Painting Texture

th

the 19 century Terrazzo

Mosaic

Set metal strips for separations on

Originate from the

Early for

sand concrete, then pour the

Northern Italy around

Pavements of

th

mixture of chips of marble, quartz,

the 15 and 16

granite and cement, cast a layer of

centuries

th

Portico; Later for Interior and

chips when half-wet, finally polish

exterior floors;

smoothly after totally formed

Durable

Assemble by small pieces of glass,

Popular in Italy and

Interior Walls

stone or other materials bonding

other Western

and Floors for

on the plaster directly or through a

European countries

large backboard

th

from the 6 to 15

high classes

th

centuries Resources from:https://www.wikipedia.org

1.1.2.2 Glass --- Transparent Layers Glass is born from soil and shaped in fire. It is made up of natural minerals composed of quartz sand, lime and potassium carbonate and artificially fired to form rare and transparent building materials, which has been used as a protecting and lighting material as building windows since ancient times. Although the composition of the glass has been almost unchanged for thousands of 35

CHAPTER 1 EXISTING MATERIALS AND CRAFTS

years, the production crafts have changed dramatically (Table 1-6). Regarding the nineteenth century as a watershed, the original glass out of handicraft production gradually transformed into machine manufacturing, and through technology innovation, the glass developed towards larger scales, smoother surface and better transparency. Furthermore, the methods of glass fixing have gradually changed from the original lead clamping or gold and copper frame glued with sludge, into cheaper iron (steel) or durable zinc (aluminum) frame prefabricated with silica gel. In addition, the craft of adding different metal powder into the process of glass, also brought a peculiar material to the church and other buildings --- stained glass. The appearance of it not only formed an “illuminated wall decoration” through a variety of colors inlaid stitching, but also brought the mysterious gorgeous glory to the previous depressed desolate space. Table 1-6 Main Types of Glass in Old Buildings Name

Origin Time

Explanation

Features

cast glass

Ancient

Pour liquid glass into the mould and

Low Transparency,

Roman

smash with rollers; Form glass plate after

has deformation and

Times

cooling

limited size

crown

1670s

Blow melted glass into sphere and smash

Visual Deformation

glass

England

into plane; Rotate quickly into a circular

can be reduced by

shape with pole after tempering and put

milling; Can be cut

into sand for cooling to form a circular

into smooth plane but

glass plate with a different thickness from

with small size

General View

center to edge cylinder

1830s

Cylindrical glass blown by hand or

Larger size and

glass

England

machine; After cutting two edges and

Smoother surface

along longitudinal side, spread to form a

compared with

plane and form glass plate after cooling

crown glass

Put a tank block into a large pond of liquid

Relatively smooth but

drawn

1910s

glass

glass and extrude glass through a series

irregular thickness

of rollers to form a strip of glass; Form

due to temperature

glass plate after cooling

change; Probable visual deformation

float glass

1950s

Pour melted glass into one end of a tin

Perfect smooth

pool and then liquid glass float on the

surface with a very

surface; Through control tin flow below,

large size in one

glass moves forward and form smooth

direction

surface; Form glass plate after cooling Resources from:http://mikegigi.com/periodgl.htm

1.1.2.3 Ceramic Roof Tile --- Solid and Local Fifth Facade It is no doubt that a city can be distinguished through the observation of the roof tiles. Let alone the stone slab tiles used in England or the wood tiles in Switzerland, even the most common 36

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

reddish-brown roof tiles, can distinguish the geographical location of the building through the different sizes, shape or lapping methods. It is because roof tiles as the cladding materials of the roof, not only need to accept the most direct climate test, but also form the fifth facade of the building visually from a bird eye view of the city landscape. Ceramic roof tiles as the oldest roof cladding materials, has a very long history of development. From the early ancient Greek and Roman tiles to the later special tiles adapted to the characteristics of various areas (such as the Spanish tiles, the French tiles, etc.), the forms are quite affluent18. But in terms of the general shapes, it can be divided into flat tiles and pan tiles, as shown in Figure 1-21.

Figure 1-21: The Images and Crafts of Flat Tiles and Pan Tiles (The Preservation and Repair of Historic Clay Tile Roofs)

Figure 1-22: Different Fixing Crafts of Roof Tiles (The Preservation and Repair of Historic Clay Tile Roofs)

There are two lapping methods between tiles: interlock and overlap. The former needs the tile itself has tongue-and-groove at sides and through lapping it, forms a complete single-layer of tile surface, which is economical and light, and quite suitable for the regions with much rain and snow; And the latter is covered the roof through overlapping the tiles partly, which a little bit heavy and more suitable for those regions with slow roofs. And whether for flat tiles or pan tiles, there both exist these two lapping methods. In addition, in order to fix the tiles securely on the roof structure, the crafts can be further divided into the following four categories: battens, nailing, wire ties and tie locks (Figure 1-22). Besides the first one is used for flat tiles, the left three ones are for the cover tile (those tiles can’t directly contact with the roof structure or supporting strips)of the pan tiles. Especially for the cover tile connected with copper wire, mortar will be filled between it and under tile in order to strengthen the stability. 18 There may be various interpretations for a certain word or an object in different regions when we are discussing the classification of different ceramic roof tiles. For instance, the Spanish tiles in the American context is the Single Roman tiles in England, which are mostly used in France and more common than the so-called French tiles in United States; While the so-called Mission tiles for Americans are the Spanish tiles for European countries. Thus, in order to avoid the corresponding relation between the name and the object of each tiles, there is no more classification and explanation further in this thesis.

37

CHAPTER 1 EXISTING MATERIALS AND CRAFTS

█ 1.2 MAIN PROBLEMS (ORIGINS OF DIACHRONIC INTERFACE) Although the old buildings are able to secure their roots and provide long-term dwellings for people by using the materials and crafts mentioned above which are constantly optimized and improved, with the changes in the world, the old buildings are more or less facing some problems, which promote the birth of the diachronic interfaces.

a

b

c

Figure 1-23: Practical Cases for Different Diachronic Interfaces (a)

Chiesa Santa Maria dei Greci in Agrigento (b) The Portal of Gaudi Museum in Madrid (c) Maison de Verre in Paris

●1.2.1 CONSOLIDATION FOR DAMAGE OF THE STRUCTURE First of all, it is obvious that there will be a lot of problems about the damage of the existing structure and materials in the old buildings. Although the local wall peeling can be improved by some simple remedial measures, there are still a lot of more serious structural problems on the existing materials. For example, many historical buildings that have survived in the fierce bombing of World War II, are incomplete or even crumbling. If they are not properly reinforced, they may collapse, fall, and even removed at any time. In addition, in many archaeological excavation processes of the old buildings, due to the lack of the original soil loads and protection, the buildings also need appropriate structures to reinforce or cover (Figure 1-23, a). Furthermore, the removal of some previous components, will also lead to the structural instability and to make up with the substitution of new components. Among them, the existing structural material objects to be studied, are mainly masonry walls and reinforced concrete floors, followed by some rods like iron, steel and wood. This is not only due to the poor bending and tensile properties of masonry and concrete, but also because of the simplicity of the removal of the rods or the reinforcement at local nodes (which are less likely to be directly observed from the previous materials). As a result, the interventional materials and crafts for masonry walls and concrete walls or floors are much more diverse, better to reflect the aesthetic relationship of the old and new structures. Therefore, the diachronic interface that is caused by these reasons can be generally referred to as the structural interface, by selecting the appropriate structural materials and crafts, to achieve the stability and optimization of the old building structure. ●1.2.2 SUPPLEMENT FOR LACK OF THE ENCLOSURE Secondly, the explosion of the structural materials or the aging of the cladding materials in the old buildings will also cause a variety of construction problems. Such as the thin walls need to be added insulation measures, open courtyards or apertures need to be closed or cut off (Figure 1-23, b), the old roofs need some waterproof treatments, bare pillars need some fire coverings and so on. Even in the interior, recovering the grounds, ceilings or walls with new cladding materials, also 38

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

aims to better protect the existing structure of the old building and extend its life cycle. These interfaces seem more local, trivial, and sometimes even completely covered, which are easy to be ignored or overlooked. Although most of them appear on the surface of the old buildings, such as wall plaster, roof tiles, in fact the real situation is that they are applied to the existing structural materials, such as masonry walls or reinforced concrete floors under the plaster, wood frame under ceramic roof tiles. Therefore, only through the patient observation and careful elaboration of constructional design which is oriented to solve function problems, the expression of the dual goals (performance and aesthetics) between old and new can be achieved at the same time. Thus, this kind of diachronic interfaces is called constructional interface, which makes up and improves the construction aspects of the old buildings through the proper use of the interventional cladding materials and crafts. ●1.2.3 ADDITION FOR ALTERATION OF THE SPACE Finally, unlike the former two which are from the point of view of the protection of the old building itself, the existing old building materials will also face the configuration challenges from the subjective space changes brought about by the users. Whether it is to add a new volume on the roof or the wall of the old building (Figure 1-23, c), or to implant a new structure inside the old building, or to insert a new space adjacent to the old building, due to the spatial variation from functional changes will always lead to the direct relationship with the existing materials through the intervention of the new materials. This kind of relationship is generally divided into two categories: First, within the old building, generally structural interfaces, compared to the structural interfaces derived from the damage of the existing structure, have a greater range of the choices of the interventional materials, but still regard structure as the design focus and consideration (thus also classified into the structural interfaces analysis in Section 3-1); Secondly, outside the building, especially in the extension cases, because there is no direct structural or constructional contacts between the old and new, the configuration between the materials and crafts becomes the primary requirement, while structure and construction follow. It is because for this type of interfaces, the most notable matter is not the specific position of the direct contact between the existing and interventional materials, but is the entire configurational convergence formed by these materials, which can be especially appreciated through the façade convergence. Therefore, the second type of the interfaces mentioned above is called the configurational interface, which establish a configurational echo and coordination with the old building through the specific interventional surface materials and crafts. All in all, the emergence of these diachronic interfaces is the inevitable and primary concern in studying the old building rehabilitations. And its appearance is also closely related to the existing materials and crafts of the old buildings. Hence, in this special section to elaborate as an inference, not only for the introduction of the classification of the three types of diachronic interfaces in the following, but also to affect the thinking and consideration of the specific design methods. All the outcomes about this chapter have been summarized in the Appendix 1. 39

CHAPTER 02 INTERVENTIONAL MATERIALS

CHAPTER 2 INTERVENTIONAL MATERIALS

█ 2.1 GENERAL CATEGORIES Compared with several existing materials in the old buildings, the interventional materials that used nowadays in the old building rehabilitation have a more diversified trend. Some traditional materials have differentiated: masonry is no longer occur as a structural material to people, of which heavy stone has gradually transformed into a more lightweight cladding; wood is no longer as a simple natural roof structure, the emergence of plywood and OBS have completely subverted the previous properties of natural wood; glass also gets rid of the role of a thin layer of the envelope, glass block, U-shaped glass have also made the possibility of a transparent structure. On the other hand, the birth of some new materials, also has promoted the old building rehabilitation to demonstrate a richer features: not only does the metal sheet protects and decorates the old buildings, but also leaves the special texture of its own era; the lightness and durability of the plastic has also brought a touch human care and feelings to the old buildings after technology revolution. As a consequence, the clear definition between structural materials and cladding materials19, has already been shaken and vague.in the development of materials science and technology for the time being. Therefore, according to experience and knowledge gained from the case study, the interventional materials for the old building rehabilitations are divided into the following three categories: structural materials, surface materials and dual (attributes) materials. ●2.1.1 STRUCTURAL MATERIALS 2.1.1.1 Brick --- Energy-saving Block of Traditional Appearance The brick used in the old building rehabilitations nowadays, although has a quite similar appearance with the standardized clay brick20 in the past, there still are some slightly differences in size and colors. However in fact, the selection or process of the raw materials for it is totally different and tends to a more environmental-friendly and sustainable direction. Firstly, the clay brick, through more frogged or perforated to save the non-renewable raw material of the soil effectively, results in the new blocks like frog bricks and perforated bricks (Figure 2-1, a ). At the same time, the air holes left in the block also have better thermal insulation properties. Secondly, on the choice of raw materials, except for clay, some of the industrial production of waste (such as slaked lime, quartz sand, coal ash, stone chips) has begun to be used as the basis for the production of bricks, which finally forms the blocks such as Calcium-silicate bricks and Cement bricks (Figure 2-1, b). Furthermore, it has also greatly reduced the high-temperature energy consumption during the producing process and the impact of a large number of combustion on the environment. In addition, the recycling of waste bricks has also been practiced in more and more old building rehabilitations. Not only because the cost of these materials is much lower and the resources are richer than those of the new clay bricks, but also more importantly, most of them covered with a 19

The reason why using “Cladding materials” rather than “Non-structural materials” or “Decorative materials” opposite to “Structural materials” is mainly because: (1) “Non-structural materials” even include the constructional materials such as insulation or waterproof materials existing in modern architectures which are much more complicated and broader; (2) “Decorative materials” defined in the Stone of Venice by John Ruskin, are more related to the subjective aesthetic study of building decorative figures or stripes the meaning of which doesn’t coincide with that of this thesis. 20 Standardized clay brick is made up of natural clay containing minerals, lime, iron oxide and etc., which is mixed with water , extruded and cut into proper dimensions, air dried and baked in high temperature. 42

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

natural patina, which can form a dialogue with the old building materials without any modification.

Figure 2-1: Forms and Textures of New Bricks https://www.pinterest.com/

2.1.1.2 Concrete --- High-efficient Mixture under Traditional Casting Compared to the previous reinforced concrete in the old buildings, the vast majority of the concrete used in the rehabilitations is not much different, but the internal reinforcement used to bear the tensile-bending has been basically replaced by steel bars, which is related to a corresponding reinforced concrete specifications (such as Eurocode 2). However, with the appearances of Glass Fiber Reinforced Concrete (Glass Reinforced Concrete), High-Performance Concrete and Ultra HPC21 in the second half of the 20th century, not only has the material optimization of lightness and stiffness occurred on the physical structure extent, but also has created a richer texture or shape for the old buildings. One of the most noteworthy is the translucent concrete invented by the Hungarian in 2001. The use of the mixture of non-coarse aggregate and transparent glass fiber prefabricated, in the molding of concrete, can produce a semi-permeable effect like curtains, greatly changing the previous thick impression on the concrete (Figure 2-2).

Figure 2-2: Different Types of New Concrete http://www-personal.umich.edu/~eltawil/uhpc.html & https://theconstructor.org/concrete/transparent-concrete-light-transmitting-concrete/9271/

2.1.1.3 Steel --- Reversible Anchorage of Traditional Profiles With the progress improvement and popularization of steel, it has been completely substitute iron in the old building rehabilitations. No matter it is hot finished or cold formed, cast in mould or extruded through rollers, steel can be made into any form such as angle steel, I-beam, T-beam, flat steel, channel steel, square steel, round steel, steel bar and so on (Figure 2-3, a) for different parts, and through become a much more diverse figure by the various combinations between the profiles, 21

High-Performance Concrete is different from traditional concrete in terms of the selection of additive and W/C ratio (water and cement). In most cases, it can reach a certain load capacity without the setting of inner steel bars. While for Ultra HPC, the strength property is improved through adding steel fibres inside the traditional concrete. 43

CHAPTER 2 INTERVENTIONAL MATERIALS

such as steel composite floor (Figure 2-3, b). Nevertheless, compared to a variety of optional anchorage methods before in the old buildings, the steel anchorage in the rehabilitations tends to use bolt connections. This is not only because the bolt itself has the intuitive mechanical expression and the error tolerance between the old and new parts, but also more importantly, the new part can be removed at any time without causing significant damage to the previous part. This reversible feature is also an adequate protection and respect for the original values of the old buildings.

a

b

Figure 2-3: Main Types of Steel Profiles and Composite Floor

●2.1.2 CLADDING MATERIALS 2.1.2.1 Stone --- Abundant Traditional Variants The previous natural stone is gradually retreating from the stage of history as a structural material due to its heaviness and relative poor capacity compared with concrete, but owing to its harmonious appearance and compatibility with masonry, has become the most extensive cladding material for old building rehabilitations. According to the complexity of the producing processes, stone can be divided into natural and artificial stones: Natural stone retains all the material properties of the previous stone, from texture and color to corrosion and moisture. Slate, which is mined from natural rocks and cut evenly through machines, is the most common form, the surface of which can obtain the similar texture of the old building material by polishing, honing, sawing, flaming, hammering, etc. (Table 2-1). In addition, at the outdoor flooring location, there also exist different types of stone textures, such as pebbles, gravels and other materials to work as a buffer for the transition. Table 2-1 Different Surfaces of Natural Slate (Marble as Example)

polished

honed

sawn

flamed

hammered

Smooth and reflected

Satiny surface with

Semi-smooth regular

Irregular coarse

concave-convex rough

surface; Generally for

some small holes;

surface; As wall,

surface; Anti-fire and

surface; As exterior

Crystalline stones; As

As wall or floor

door(window) frame,

anti-corrosion; As the

wall cladding

wall or floor cladding

cladding

courtyard(landscape)

cladding for

ground cladding

flammable materials

Resources from:http://www.chooseby.com/archive/ 44

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

And about artificial stone, it is a synthetic material corresponding to those mixtures formed by adding other materials into stone powder or particles, such as plaster (see Section 1.1.2.1) and plasterboard (cement or stucco board), which can protecting the existing walls or floors. Compared to the traditional handicraft plaster that requires a lot of labor, the prefabricated cement-fibre board in recent years, is more suitable for rapid construction and dismantlement and catering to the need of temporary or reversible rehabilitations. 2.1.2.2 Metal --- High Coriaceous Sheets Although there are a large number of different kinds of metals in nature, but due to the impact of activity and rarity, the species which can be used on the buildings are very limited. Coupled with the visual need of coordinating with the old building, the metal used for the rehabilitations is mainly copper, aluminum and zinc in the form of sheet. Similar to the use of these metal sheet, there are also different types of sheet of steel22, such as weathering steel, galvanized steel and stainless steel (Table 2-2). Table 2-2 Main Metal Flats and their Characters Name

Appearance

Properties

Application Positions

Copper

Reddish brown at begin,

Inert Metal; Good corrosion

Exterior covering like roof

oxidized into aerugo or even

resistance and waterproof;

sheet; water pipes

aquegreen with age

Perfect ductility but expansive

Originally light grey, becomes

Relatively active metal; Easy

Exterior cladding such as

dark grey when contacts with

reacts with other metals, need

wall sheet, roof sheet;

air

surface protection or used

Aluminum alloy frame

Aluminum

separately; light, stiff and relatively cheap Zinc

Originally light grey and

Relatively active metal; Hard to

Exterior cladding such as

becomes light blue-grey

get rusty with high density; Not to

wall sheet, roof sheet or

exposed to the air

contact with copper, plaster and

enclosed strip

acid wood Weathering Steel

Galvanized Steel

Stainless Steel

Yellowish brown at begin,

Low content alloy with high

Exterior and interior cladding

darken to brown with age

strength; the alloy surface to

such as wall sheet, door

protect from corrosion

(window) frame

Whitish grey at begin and

Due to surface plating, the inner

Interior cladding such as wall

become uneven grey oxide

steel exposed after scratch is

sheet, door (window) frame

when contacts the air

easy to decay; Relatively low cost

Remained whitish grey

Due to the resisting metal added

Interior small area of

reflected surface

during the steel-making process,

cladding such as ceiling,

material is uniform to resist

skirtboard

corrosion; Relatively high cost

Resources from: Materials For Design, 2006

2.1.2.3 Plastic--- Transparent Light Shells Since this new type of synthetic materials has a relatively short history for building practices and construction, coupled with its slightly modern image, plastic is still less in the old building 22

45

CHAPTER 2 INTERVENTIONAL MATERIALS

rehabilitations. However, in view of its own excellent stability and corrosion resistance, accompanied with more and more processing technology innovations, there is still a relatively broad space for its development in the future. In particular, two of these have been currently more fully applied to the new building as cladding materials (Figure 2-4), translucent Polycarbonate (PC) and high transmittance ETFE (ethylene tetrafluoroethylene polymer). Not only have they overcome the heaviness and fragility of the traditional glass but also have created shells in any size and shape through a simpler processing technology to adapt to any part of the old building rehabilitations.

Figure 2-4: Main Plastic for Rehabilitation (PC sheet and ETFE film) (https://www.pinterest.com/)

●2.1.3 DUAL (ATTRIBUTES) MATERIALS 2.1.3.1 Wood --- From Natural Unitary to Artificial Diversity Table 2-3 Main Types of Synthetic Wood Name

Producing process

Properties

Application Position

Glulam

Glued with more than three

Relatively high

Structural position

layers of wood board piling up

strength

such as column or

horizontally

Plywood

General View

beam

Composed of at least three

Medium strength;

Cladding for Façade,

boards with interweaved

Good dampproof

roof or decorative

texture, glued together in high

and shrinkproof

interior floor,

Mix wood chips and organic

Medium strength;

Rigid cladding for wall

glued materials together and

Good dampproof

and floor

extrude in high temperature;

and anti-fire

Sand the surface and make

capacity

temperature and compression with waterproof chemical materials Chipboard

chips vertical to the orientation of board

Resources from:Constructing Architecture Materials Processes Structures - a Handbook, 2005

The wood used in the past in the old buildings, is mainly natural lumber - timber and wood board, the former is for the roof structure (see Section 1.1.1.4), the latter is mainly as the indoor surface 46

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

layer. Due to many properties of the natural wood, such as size, moisture, corrosion, strength and durability, there must be some certain limitations on utilization. With the development of technology, the emergence of a large number of synthetic wood, not only has made up for the defect of natural wood, attracted more architects, but also more importantly, the synthetic wood (just like artificial stone or new block) has better responded to the needs of energy saving and environmental protection through the use of the residual or discarded materials to do a secondary process. While These synthetic woods mainly include Glulam, Plywood and Chipboard 23(Table 2-3). richer structural components can be formed by means of a combination (Figure 2-5), such as Box Beam, I Joist, or inserting steel plates such as Flitch Beam.

Figure 2-5: Main Types of Composite Synthetic Wood Structural Components (https://www.pinterest.com/)

2.1.3.2 Glass --- From Transparently Weak to Diversely Solid Glass as a transparent or translucent material is generally used for lighting and enclosure. With the development of glass manufacturing process, now most of the glass used in the rehabilitations is laminated glass with good insulation properties due to the inner hollow, ensuring the visual permeability as well as the indoor energy-saving effect. At the same time, a series of new materials such as hollow glass block, sandblast glass, printed glass, Channel glass (U-shaped glass), etc., have achieved different visual transparency and experience of color pattern richness by different production processes (Table 2-4). Table 2-4 Main Types of New Glass Name

Producing process

Properties

Application Position

Hollow Glass

Melted two rectangular glass

Generally translucent;

Curtain wall,

Block

cups oppositely along the

Thermal and acoustical

separation and floor

openings; Bond with mortar

insulation

in small scale

Use spray gun to blast sand

Translucent; Relatively

Exterior curtain wall

on the glass surface to form

coarse surface

and interior

General View

or fixed into steel frame

Sandblast Glass

concave and convex

separation

23

According to Constructing Architecture Materials Processes Structures - a Handbook, there is another synthetic wood --- Fiberboard. However, since it is mainly used as the basis of insulation of wall, floor or furniture which neither belongs to structural nor cladding materials referred in this thesis, here it isn’t further discussed. 47

CHAPTER 2 INTERVENTIONAL MATERIALS Name Printed Glass

Producing process

Properties

Application Position

Generally screen print,

Generally translucent;

Exterior curtain wall

stamp the grid film with

figure with different

and interior

ceramic ink onto the glass

colors to obscure view

separation

General View

and fired to form the figure

Channel

Heat ordinary glass plate

Generally translucent;

Curtain wall and

Glass

and bend two sides of it 90

Easy to maintain and

curve wall in large

degrees by machines; one or

assemble; Thermal and

scale

two pieces for each unit and

acoustical insulation

bond with silicone resin

Resources from:https://www.wikipedia.org

In addition, in some advanced old building rehabilitations, structural glass which can bearing loads has been invented and applied, such as laminated glass slabs and solid glass blocks. The glass is cast from a specific mold, and bond together with transparent silicone resin or other new binders, presenting a nearly crystal appearance. And this kind of brick-like weaving process, also makes the new part show a more humble and reverent attitude towards the old building. █ 2.2 SELECTING FACTORS (FOR THE INTERVENTIONAL MATERIALS) Although there has been a general summary of the various materials that may be used in the old building rehabilitations, which is like a doctor who has fully mastered all the relevant knowledge before the surgery, when dealing with a specific problem, the expert still needs to foresee the result and make the inference at a certain range according to the practical situation. Therefore, before starting to talk about the interventional crafts belonging to each situation, we should have a better overall understanding of the design problem “what factors affect the selection of the interventional materials” in order to provide certain targeted guidance for the specific design operations. In order to better explain the content of this section, 115 typical practical rehabilitation cases in Western Europe after the 1930 have been chosen and analyzed (see the specific locations of each case in Figure 2-7 and related data in the Appendix 2 Table A2-1), which have taken into account four macro-factors of the cases: Times developments, Regional differences, Functional requirements and Architect preference. ●2.2.1 Times Developments There is no doubt that the material is in close contact with the development of the times. And in the material selection of the diachronic interface, this is mainly reflected on the material utilization changes brought about by technology innovation and social evolution. As can be seen from Table 2-5 directly, steel, glass and stone are the interventional materials with much higher frequency; wood, concrete and metal follow while brick and plastic are less used. However, if focus on each line separately, namely the change and evolution of the time, there are still a lot of secondary tendencies about each material can be discovered:: for example, brick, metal and plastic show a growing trend; glass and stone are slightly down; steel is basically stable while concrete and wood have a large fluctuation. 48

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION Table 2-5 Frequency of Use for Different Interventional Materials at Different Periods

1.0

1.0

0.8

0.8

0.6

0.6

0.4

0.4

0.2

0.2

0.0 1930-1960s

1980s Brick Steel

0.0 1930-1960s

2000s Concrete Wood

24

1980s Glass Metal

2000s Stone Plastic

Combined with the technological developments of these materials since the 20th century, it is found that the uniqueness of materials and the manufacturing process greatly affect their frequency of use. Steel as a structural material with high strength and light weight, low price and reversibility since the 20th century, has become the unique, irreplaceable material among all the interventional materials and therefore maintains a high structural utilization of the rehabilitations; And about glass, though it once had the same unique place as steel, has been partially replaced by plastic that was invented and applied in the second half of the 20th century (Figure 2-6, a); with the same fate, synthetic stone, the cladding material which in most cases requires relatively complicated handicrafts, has also been gradually substituted with the metal panels with more efficiency and standardization. Therefore, the development of different materials with technology innovation is the key for changing tendencies between different materials and the selection of materials.

a Figure 2-6: Different Interventional Material Use for the same Situation in Different Times

b

(Restauración de la Antigua iglesia de Corbera d’Ebre; Building in Existing Fabric: Refurbishment, Extensions,2003)

In addition, the common concept held by human society in different periods, also has a deep 24

The data in the vertical axis in the graph is in the unit of percentage (from 0-1), which means the ratio between the amount of the appearance of a certain material in the specific period and the overall number of the cases in the same period. The same situation is also for Table 2-6 and 2-7 in the following. 49

CHAPTER 2 INTERVENTIONAL MATERIALS

impact on the selection and utilization of interventional materials, in which the most concerned is about the appearance of materials and environmental sustainability issues. For example, in the early 20th century, metal panels were often rejected by most people for old building rehabilitations because of their excessively shiny gloss while stone was generally selected as a more traditional and well-known material (Fig. 2-6, b); Brick, concrete and wood, although they are closer to the traditional appearance, still suffered different situations owing to the constant impact of the energy crisis and sustainable development from the second half of the 20th century: concrete has been reduced in the 21st century because of its irreversibility of the raw material; While brick gained more chance to be used due to the improvement of raw material and producing process (mentioned in Section 2.1.1.1); And wood has a certain recovery of utilization after the 1980s due to the spread of the synthetic technology (wood chips glued or laminated), after the 20th century. ●2.2.2 Regional Differences Secondly, the selection of interventional materials also needs to consider the local conditions. This is mainly due to the fact that there is not only the difference between the natural and geographical situations, but also the differences between the laws and regulations of countries.

Figure 2-7: Most Frequent Used Interventional Materials in Different Climate Regions in Western Europe

Figure 2-7 defines four geographic regions of Western Europe based on climate zones: marine climate, continental climate, mountain climate and Mediterranean climate. From the data analysis in Table 2-6, it is obvious that the characteristics of mountain climate is more distinct: in 50

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

mountainous areas, due to high altitude, large temperature difference and vast forest resources, wood and concrete will always be selected as the main interventional materials while steel and metal are rarely used owing to the inconvenient transportation. And the remaining three climate areas are much similar, only have their influence in the selection of certain interventional materials on the extent: for instance, wood, stone and concrete are less used in marine areas due to relatively scarce forest and stone resources and on the contrary, more steel, glass, brick and other industrial materials are selected because of the high industrial production level; stone is widely used in the Mediterranean region due to the rich geological rock stratification below; while the continental climate in between, enjoys a diverse use of interventional materials due to the both-side influences. Table 2-6 Frequency of Use for Different Interventional Materials at Different Regions

1.0

1.0

0.8

0.8

0.6

0.6

0.4

0.4

0.2

0.2

0.0 Mar

Con Brick Steel

Mou

Med Concrete Wood

0.0 Marine

Con Glass Metal

Mou

Med Stone Plastic

Figure 2-8: Different Interventional Material Use for the same Situation in Different Countries

In terms of the countries, there are also different tendencies for the selection of interventional materials due to the specific laws and regulations referred to old building protection and repair in each country (Figure 2-8). For example, the Rome Charter, which was carried out in Italy in the 1930s and passed on the Italian theory and practice of "evaluative repair", clearly stipulates that the materials used in the treatment of old buildings should be reversible, authentic and aesthetic. Therefore, the original protecting concept of old buildings has a deep influence on the old building 51

CHAPTER 2 INTERVENTIONAL MATERIALS

rehabilitations afterwards in Italy, with the prior choice of a variety of traditional materials (such as stone and concrete). In contrast, for Spain, which is also in the same climate area as Italy, in the National Arts and Cultural Heritage Protection Act (1933) implemented at the same period, more focus was put on the reuse issues, and therefore more the durability and stability of the interventional materials were emphasized while the pursuit of traditional materials was not so strong as that of Italy. Coupled with a consistent aesthetic tolerance and pragmatism in the old building rehabilitation in Spain, more new materials (such as weathering steel plate) become the most representative of the characteristics of Spanish rehabilitations. As for the British and French divided by the English Channel, due to the deep implementation of the concept of listed buildings, monuments inscrits and conservation areas, more use of light or transparent, industrial materials (such as steel and glass) have been utilized to accompany with the overall environment and traditional style of the old building. ●2.2.3 Functional Requirements In addition, some old buildings are also facing the intervention and application of new materials because of the loss of the original function (such as religion, military, palace and industrial buildings) or the improvement of the performance standards (such as updating museums and residence). In the data analysis of the cases, it is found that about 85% of the abandoned old buildings will be reused as cultural buildings (open to the public). Although the functions after the rehabilitations are quite similar, there are still lots of differences of the selection of interventional materials due to the differences of the previous materials, structure and space affected by the previous functions. Table 2-7 Frequency of Use for Different Interventional Materials with Different Previous Functions

1.0

1.0

0.8

0.8

0.6

0.6

0.4

0.4

0.2

0.2

0.0

0.0 Rel

Mil Brick Steel

Pal

Ind Concrete Wood

Rel

Mil Glass Metal

Pal

Ind Stone Plastic

On one hand, as can be seen in Table 2-7, except for steel, the frequencies of use of the other materials in old buildings with different previous functions show some differences: wood is more used in the previous religious buildings to create a cozy atmosphere with the original wood roof structure while on the contrary, more solid structural materials such as steel and concrete are used in the previous military buildings to highlight the defense features of the original fortresses; The previous palace buildings preserve or enhance the original gorgeous and noble space through the rich use of stone; And the previous industrial buildings reflect the achievements of artificial products under the technology innovation through more synthetic materials such as plastic and 52

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

glass. On the other hand, for those old building remaining their previous functions, the interventional materials are also used to enhance the corresponding performance. In terms of residence, different interventional materials will be used on the facade or interior as claddings to improve thermal or acoustic insulations (Figure 2-9, a). For example, the addition of steel, hollow glass and metal sun visor on the facade forms a glass balcony, which expands the area as well as provides maintenance and insulation for the existing wall; while wood and artificial stone will be normally used indoors to enhance the space comfort and living quality; In contrast, speaking of museum upgrades, a larger and more comfortable exhibition space is achieved through extension and interior decoration (Figure 2-9, b). For instance, the traditional materials such as masonry and concrete are used next to the existing building to form a visual continuity on the facade, or glass and steel are used for covering the original courtyard so as to obtain a greater interior space with skylight.

a

b

Figure 2-9: Different Interventional Material Use for Different Functions (Building in Existing Fabric: Refurbishment, Extensions, 2003)

●2.2.4 Architect Preference Finally, in addition to these relatively objective factors mentioned above, the real richness and diversity of materials in old building rehabilitations is achieved by the real creativity and comprehension of the architects. "There are a thousand Hamlets in a thousand people’s eyes", although the rehabilitation is relatively more objective than the new construction and limited by more factors, for those architects who have their own special style or concept, they definitely know how to use their familiar materials and apply into the specific old building rehabilitation, even bring more finishing touch to it, in my opinion which is the real understanding towards the diachronic interface in old building rehabilitation.

a Figure 2-10: The same Interventional Material Use in Different Buildings by the same Architects (http://www.rsh-p.com/ & https://davidchipperfield.com/) 53

b

CHAPTER 2 INTERVENTIONAL MATERIALS

For example, Richard Rogers, one of the highly regarded representatives of High-Tech, is particularly interested in the manifestation and expression of a modern rational structure with steel: whether it is the interior steel truss floor hung with the steel cables between the original iron pillars in the Billingsgate Market in London, or the V-shaped boxed steel columns supporting the original facade of the brick wall in the Center Comercial Arenas de Barcelona, they both use special steel structures complying with structural forces to reinforce the characteristics of the old buildings as well as the interaction between the old and new (Figure 2-10, a). Another British architect, David Chipperfield, who is keen on the old building rehabilitation, always likes to use the recycled handmade brick in the old buildings: from the new brick facade with the lines of feet decorations making up the damage in the Neues Museum in Berlin, to the brick covering façade along the street of Gallery Building 'Am Kupfergraben 10 in Berlin, the subtle different use of the interventional material always ensures the integrity of the historical texture while follows the plain practices of the identifiable old and new (Figure 2-10, b). Besides, the Italian traditional architect Guido Canali also continuously uses the suspended glass exhibition panel with steel cables in many different museum rehabilitations. Whether is in the Galleria Nazionale di Parma, or in the Siena il Museo Ospitale, these lightweight floating boxes are designed with exquisite and wonderful nodes. Not only do they show all kinds of precious collections in a more transparent way, but also form an organic link with the original space or structure of the old building and perfectly present the refined materials application of diachronic interface in Italian tradition with classical atmosphere (Figure 2-11)

Figure 2-11: The same Interventional Material Use in Different Buildings by the same Architects (Santa Maria della Scala: Museo Archeologico e Sale espositive, 2003)

Hence, from the analysis above, a series of referenced factors and conclusions for material selection have been inferred and verified. However, it is clear that these analytical results should not be necessary or inevitable limits to the material selection of the diachronic interface. After all, hundreds of study cases can’t cover all the situations and serve as absolutely true and powerful laws or regulations. Thus, I only hope that whenever we are facing a specific old building rehabilitation, we architects will not only wantonly exert our professional ability and imagination, but also carefully treat the old building in a variety of context (such as the natural environment, the history and culture, the previous function of the old building, etc.) and show fully respect for the old building through the proper use of the interventional materials. All the outcomes about this chapter have been summarized in the Appendix 1. 54

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

55

CHAPTER 03 INTERVENTIONAL CRAFTS

CHAPTER 3 INTERVENTIONAL CRAFTS

Figure 3-1: Different Types of Diachronic Interfaces based on Relations between Existing and Interventional Materials

After clarifying the main types of existing materials and interventional materials for old building rehabilitations as well as the types and characteristics of diachronic interfaces while before the further study of the specific interventional crafts, the corresponding relationship between these two layers and study object has been expressed through Figure 4-1. As is shown in the Figure, the grey portion is the existing (old) materials of the diachronic interface appearing in the old buildings while the orange portion is the interventional (new) materials of the diachronic interface to be applied to the old buildings, besides in the middle, there are three icons representing the types of diachronic interfaces: from left to right are the structural interface, constructional interface and configurational interface. Furthermore, the connection lines show the correspondence between the old and the new materials: the structural interface is the new structural material corresponding to the old structural material, the constructional interface is the new cladding material related to the old structural material, and the configurational interface is the new material paralleled with the old cladding material. 58

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

█ 3.1 STRUCTURAL INTERFACE According to the analysis of Section 1.2.1, this kind of diachronic interface, usually appears at the damaged position of the old structure, occasionally may also exist in the space of the old structure after some function changes. In general, it is the place where the new structural materials are applied on the old structural materials, so the following will be discussed in the classification of the positions of the structure elements. In addition, in order to better reflect the characteristics of this type of diachronic interfaces, all the analyses will be in the form of explosive axonometrics in order to clearly and directly show the links and forms of the structure in various crafts. ●3.1.1 For Masonry Structure Although such structures include structural elements such as columns, walls and vaults, it is clearly the most common and abundant one is the wall that encloses interior space and bears all the loads. Therefore, the corresponding new structural materials are also the most diversified: 3.1.1.1 Brick Applied to Masonry Wall It is essential to use the same material (brick) as the existing one (masonry wall) in the diachronic interface. This means that not only does the new brick itself need to be different from the original structure of the masonry in terms of the size, color or texture, but also through the traditional process but also it can also optimize the structure and passes on skills through the technology change which is adapted to the era as well as based on the traditions. Thus, in addition to the craft of ordinary masonry (bond with mortar), the crafts of the brick wall filled with concrete or built-in steel column can be practiced to reduce the self-weight and enhance stability (Figure 3-2).

a

b

c

Figure 3-2: Different Crafts between Existing Masonry Wall and Interventional Brick (a)

Ordinary Solid Masonry (b) Brick Wall Filled with Concrete (c) Brick Wall with built-in Steel

For example, in Rafael Moneo's National Museum of Roman Art, all the brick walls above the existing Roman ruins are made of a new prefabricated craft derived from ancient Roman (the Opus Lateritium): Firstly, set the high-strength bricks along the contour of the wall and bond together with mortar to form a hollow tube which is supported by a peripheral template; Then pour the concrete mixture inside the shell and stir to contact totally; Finally, assemble each unit of 59

CHAPTER 3 INTERVENTIONAL CRAFTS

prefabricated wall together with a crane on site, forming a complete high wall and continuous arch. With the combination of ancient craft and modern technology, a reproduction of the ancient Roman masonry building grows up above so that the viewer will no longer just recall the past memory from the relics but directly experience the magnificent history from the magnificent space and similar materials (Figure 3-3).

Figure 3-3: National Museum of Roman Art, Prefabricated Brick Wall Crafts and Photos (Constructing Aarchitecture Materials Processes Structures - a Handbook,2005)

The Kolumba Museum, located in the heart of the old town of Cologne, is built with Peter Zumthor's special gray bricks which have a slight difference from the old red masonry left below. If take a further observation of the walls at the diachronic interface, it is found that although the new gray brick is only 36 mm in thickness, every two new brick layers has the same thickness as the old brick layer to form a continuous horizontal line. In addition, so as to carry the upper mass load more effectively, the architect put the new brick wall straightly on the remained existing wall with a thickness of 600 mm and the new structure made up of two side brick walls with an internal steel structure: several circular columns at certain intervals are connected with perforated steel plates horizontally; And for each layer of horizontal steel plates, two zigzag steel bars are put between the brick wall and steel plate and bond with a continuous mortar to firmly fixed the brick and steel structures. However, unlike the complete solid masonry wall which conceals the construction craft, the inner steel frame can be observed both from the indoors and outdoors through the small gaps or holes left during the bonding process as well as the horizontal continuous mortar layers (Figure 3-4). Through the analysis of the characteristics of the existing material, the appropriate material and craft are selected and applied to emphasize the overall coordination and true reflection of the construction process, even create certain atmosphere in the old building by the light filtering through the peculiar material bonds.

60

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

Figure 3-4: Kolumba Museum, Built-in Steel Brick Wall Crafts and Photos (zumthor.tumblr.com/)

3.1.1.2 Concrete Applied to Masonry Wall From the construction point of view, though the use of concrete in the rehabilitation of structure is basically cast with template on-site or prefabricated in factory, there are still many rich shapes and surface textures produced by the diversity of templates and mold discharging agents, etc., which give a better resonance with the existing fabrics of the masonry. Combined with reinforcement pre-set in the mold, the concrete can play a role as any structural element on the building structure, such as walls, columns and floors.

a

b

c

d

Figure 3-5: Different Crafts between Existing Masonry Wall and Interventional Concrete Wall & Column (a)\ (b) Connected With Flexible Bedding (c) Concrete Plinth

(d) Inserting-Steel Plinth

(1) Concrete Wall Whether it is to increase the volume of the building, superimpose the new wall onto the existing one, or enclose the damaged building space and add the new wall next to the existing one, the 61

CHAPTER 3 INTERVENTIONAL CRAFTS

concrete is always a more convenient and efficient choice due to its simple construction process which only an elastic waterproof bedding is needed to be added between the cast concrete and the existing masonry wall (Figure 3-5, a & b). This is mainly due to the existence of a certain construction error of the concrete and the possible cracking problems between the two materials caused by different expansion coefficients. For example, in the upper part of the Das GelbeHaus designed by Valerio Olgiati, the original roof was removed, leaving only the horizontal elements and stone walls to fix the existing windows; The upper walls of the new pouring of concrete contact the existing part through the asphalt felt mattress and the seal on the external walls to prevent the internal leakage of water and form a flexible connection; In addition, a new ring of concrete slabs cast-in-place is fixed on the existing window peripheries to hold the new window frames. Finally a layer of white lime is painted evenly on the whole facades, not only reflecting the characteristics of the local climate in winter, but Figure 3-6: Das GelbeHaus, also making the old and new parts more similar to form a Building in Existing Fabric: complete and thick monolithic image of the building ( Figure Refurbishment, Extensions, 2003 3-6). In the rehabilitation of Castello di Rivoli by Andrea Bruno, the cross wall of the long gallery --- Manica Lunga, was removed from the walls of the original palace. Then a thick and tall concrete wall with four-storey height was poured there which is featured as ancient Roman Super-imposition Arch. Different from the complete smoothness of the ordinary concrete wall, here the architects deliberately selected a wooden template with the similar pattern as the original brick wall and arranged them in the same way as the brick masonry, which made the final surface of the concrete wall, almost with the same texture as the original brick wall and columns; And also through the Figure 3-7: Manica Lunga sub-pouring construction process, several horizontal feet lines Cast Concrete on Brick Wall with are formed which is quite like that of the façade of the ancient Wood Template Roman arena (Figure 3-7) (2) Concrete Column This type of interfaces usually appears in the remains or debris of masonry wall and contacts on the way of point supports to reduce the destruction of the existing materials and the total environment. Generally the new concrete column will be poured onto an enlarged reinforced concrete plinth and placed directly on the existing masonry walls in order to reduce the concentrated stress on them; sometimes in order to better preserve the masonry walls, a steel element is inserted between the base plate and the concrete column to act as an elastic connection (Figure. 3-5, c & d). These two different ways of connections will also leave completely different impressions on viewers. For example, the El Born Centre de Cultura and the Entrance Hall of the Ionic Temple of Artmide is a pair of good contrast. The former was transformed from a medieval remains into a 62

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

market. During the process of transformation, each iron column is connected with the lower part of the original masonry building wall through a giant concrete plinth with two-layers, the overall image of the interface seems bulky (Figure 3-8, a); While the latter uses a lighter and more appropriate connection method: the same independent plinths, but are greatly reduced the thickness of the concrete and a steel shock absorber is inserted between the upper concrete load-bearing column and the base plate so that the upper body mass can withstand the maximum load and also reduce the damage applied to the lower masonry wall. More importantly, this seemingly structural-oriented interface also inadvertently forms a discontinuity between the new structure and the original one to bring a new feeling of the floating volume and light touch on the existing building to the viewer (Figure. 3-8, b).

a

b

Figure 3-8: Concrete Columns Connected with Existing Masonry Walls (a) El Born Centre de Cultura

(b) the Entrance Hall of the Ionic Temple of Artmide

(3) Concrete Floor

a

b

c

Figure 3-9: Different Crafts between Existing Masonry Wall and Interventional Concrete Floor (a)

Ordinary Concrete Beam and Slab

(b) Steel Beam and Concrete Slab

(c) Concrete Slab with Steel Frame

Whether it is for the removal and replacement of the damage in the existing space, or the introduction of new structure after the space change, the structural preservation and optimization to the interface are needed in both cases. As a result, it is generally in the form of beams to reduce the unnecessary structural contact. In this way, not only can we take the most conventional form of 63

CHAPTER 3 INTERVENTIONAL CRAFTS

reinforced concrete beam and slab, but also can use more lightweight steel as a load-bearing beam or floor frame to reduce the self-weight of the new structure as well as play a protective role for the existing structure.(Figure 3-9).

a

b

c

Figure 3-10: Concrete Floors Connected with Existing Masonry Walls (a) Church of Saint-Francesc Convent

(b)/(c) Castelvecchio di Verona

For example, in the extension of the Church of Saint-Francesc Convent in Santpedor, the reinforced concrete beam and slab structure is used to hold a new space above the existing masonry wall. However, unlike the general concrete floor, the architect uses a rather primitive structure with a slightly exaggerated cross beam due to the large span and cantilever at one end, giving the building a dramatic visual impact (Figure 3-10,a).

Figure 3-11: Craft of Concrete Floor Connected with Masonry on the ground floor in Castelvecchio di Verona

On the ground floor and the second floor of the Castelvecchio di Verona rehabilitated by Carlo Scarpa, two different composite floors of steel and concrete are separately used. On the top of the brick wall of the ground, the original wooden floor is completely removed while a continuous combination steel beam connected by rivets is placed in the center of the walls in the longitudinal axis; Then at the center of the steel beam in each unit space, a metal bearing components is put to undertake the upper loads of the traditional brick floor and the cross-shaped concrete sub-beams; Finally, in order to highlight the use of concrete and steel, the brick slab was painted with plaster to weaken the texture. And the cement-filled recess between the brick wall and the concrete slab, the gap between the steel beam and the metal bearing component and the long seam between the 64

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

two C-shape steel beams, make all the interventional materials can be distinguished from the previous ones with linear identification and leave a definite and recognizable trace of all the interventional construction process (Figure 3-10,b & 3-11). While during the casting process of the concrete connecting bridge on the first floor, a prefabricated pouring craft was used: the steel itself as a mold frame at sides, the wooden template are arranged in the upper and lower surface of the mold, and steel bars are set in the middle of the mold in two directions. The concrete floor after pouring connects the existing masonry wall with the covered steel frame, which forms a distinct concrete floor with linear frame25 connected with the masonry (Figure 3-10,c & 3-12).

Figure 3-12: Craft of Concrete Floor Connected with Masonry on the first floor in Castelvecchio di Verona

3.1.1.3 Steel Applied to Masonry Wall The steel has the advantage of various materials, which consequently makes it so far the most widely used interventional structural material. Thus, there are a number of interfaces with existing masonry walls, which generally appear in the following three positions: roof frames, columns and beams.

a

b

c

d

Figure 3-13: Different Crafts between Existing Masonry Wall and Interventional Steel Roof & Column (a)

Steel Truss

(b) Steel Truss with Concrete Beams

(c) Steel Bedding (d) Steel Column with Concrete Beam

(1) Steel Roof Frame

25

Although in the book Time, Space & Material : The Mechanics of Layering in Architecture, Anne-Catrin Schultz compared Carlo Scarpa’s linear contour concept with Josef Hoffmann’s contoured plane theory and inferred that this kind of design skill maybe derived from de Stijl at that time, I still believe that this linear contour of all the structural elements in Scarpa’s work is not only influenced by the art style or theory, but also based on the technical requirements and innovative thinking of the craft itself. 65

CHAPTER 3 INTERVENTIONAL CRAFTS

For old masonry buildings, most of the roof structure is wood frame which is easy to decay, so it is always replaced with steel during the rehabilitation. Among them, the steel roof frames can be generally divided into two categories: steel truss (a continuous steel beam set between the steel roof and brick wall) or steel truss with concrete beams ( a strip of concrete cast between the steel truss and brick wall) (Figure 3-13, a & b).

Figure 3-14: Il camminamentofra

Figure 3-15: Complesso di

Figure 3-16: Castello di Rivoli

Palazzo Bianco e Palazzo Tursi

Sant'Agostino

Steel Truss on Brick Wall

Steel Truss on Brick Wall

Steel Truss on Brick Wall

Such as the composite roof frame of steel profiles and steel cables in the Il camminamentofra Palazzo Bianco e Palazzo Tursi designed by GTRF, is the most simple optimization form of the structure derived from the previous wood roof frame which is connected through the upper I-beam with the original brick wall. On the façade, since the brick and the I-beam are both painted with the white stucco under the previous plaster decorations, the contrast material will not be perceived easily in the shadow (Figure 3-14). In contrary, in the Complesso di Sant'Agostino designed by Studio Albini Associati, an ultra-conventional steel composite I-beam is used to connect the steel roof frame with the original brick walls. On the facade, the exaggerated girder is in harmony with the continuous arcade of the first floor and the thick columns on the ground floor, forming a three-section elevation which is similar to the classical facade. In particular, the shadow formed on the girder provided by the vertical ribs reinterprets and presents the vertical elements in the classical façade with modern materials (Figure 3-15). At the same time, from the interior, the tensile rod which should be present in the lower part of the roof truss was moved to the middle of the upper chords, forming a section similar to Mansard roof which brings about the reminiscent of the past loft space as well as increases the height of the available space in the condition that the position of the roof cornice is kept unchanged. 66

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

The latter is reflected on the steel truss of Castello di Rivoli. The ends of the upper chords of each steel roof truss are embedded in the concrete beddings and the steel purlin connected to the steel frame is abutted against the L-shaped notch of the bedding to form the indentation of the lateral thrust of the lower tensile rod. And the semicircular contours of the steel trusses also bring a experience of high and narrow interior space similar to that of the original palace. Accompanied with the white painting on the prefabricated steel elements with holes, the overall space seems quite modern with lightness and rhythm (Figure 3-17). (2) Steel Column Most of these components will appear in the upper part of the masonry wall to support the new structure of the load, and occasionally under the original masonry wall as its support, and connect through different steel or concrete beddings (Figure 3-13, c & d). For example, in the Besucherzenrum Nationalpark Unteres, a concrete bedding is set aside on the brick wall where the previous floor was and nailed with I-shape steel column Figure 3-17: Besucherzenrum supporting the roof structure. At the same time, the side of the Nationalpark Unteres concrete bedding is also nailed with the newly set steel frame Building in Existing Fabric: so that the old wall and the new structure can synergistically Refurbishment, Extensions, 2003 react together (Figure 3-17).

Figure 3-18: the Center Commercial Arenas de Barcelona under Rehabilitation (http://www.rsh-p.com/)

And the Center Commercial Arenas de Barcelona by RSPP (Rogers Stirk Halbour + Partners) is a very peculiar case of the special steel column to support the old masonry wall. Firstly, the architect lifted the circular thick brick wall up from the ground at a certain distance with cranes and support it with temporary external scaffoldings and grid columns; and then the prefabricated concrete beams were fixed to the bottom of the old brick wall from both sides through inserting steel anchorage and bolts into the reserved holes as connections; Finally, put the top part of the prefabricated red paint Y-shaped steel columns into the gap between the concrete beams fixed with bolts while the bottom part of them were connected with the cast concrete plinth through the steel plates (Figure 3-18 and Figure 2-10, a). The simple and powerful support not only highlights the rational logic of the structure and reflects the transformation of the functional needs, but also form a unification with the existing masonry wall through the color and shape: red brick wall and steel columns, white arch stones and concrete ring beam and column plinths, semicircular Roman 67

CHAPTER 3 INTERVENTIONAL CRAFTS

arches and curved concrete beams, especially the Opus Lateritium which can be tapped from the lower part of the original masonry walls, all make the old building no longer isolated and dusty, but can be organically linked with the new part, anchoring and growing together. (3) Steel Beam When the steel beam is connected with the masonry wall, generally there are two position relations: parallel and orthogonal. If it is parallel, I-steel beam and steel plates will be basically use; and if it is orthogonal, there will be more different forms of steel (such as I-beam, steel cable, steel truss, etc.) to meet the needs of different spatial or functional requirements, and set steel or concrete mats to undertake (Figure 3-19).

a

b

c

d

Figure 3-19: Different Crafts between Existing Masonry Wall and Interventional Steel Beam (a)

Parallel Steel Beam (b) Orthogonal Steel Beam (c) Orthogonal Steel Cable (d) Orthogonal Steel Truss

About the former, there is the wine museum (Lagar de Colmenar Viejo) designed by Aranguren Gallegos in a small town near Madrid, in which the clearstory window added on the top of the existing stone wall is connected by I-steel beam and L-shape steel (Figure 3-20, a). In addition, the Archeological Space in Daroca created by Sergio Sebastián Franco on the Roman ruins, a layer of thin mortar is filled at the interface between the irregular damaged stone arch and the consolidated steel beam to achieve more effective load-bearing and make the two materials fit more closely (Figure 3-20, b).

a

b

Figure 3-20: Parallel Steel Beam with Existing Masonry Wall (a)

Lagar de Colmenar Viejo

(b) the Archeological Space in Daroca

For the latter, there is a rehabilitation called the La casa Liberti, located at the facade of the old theater of Catania, by providing a rotatable steel bearing support at the upper part of the combined steel beam embedded on the existing masonry wall. It is possible to reduce the damage caused by 68

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

the deformation of the steel beam directly applied to the masonry wall (Figure. 3-21, a). In addition, in terms of much smaller loads, steel cables can also be used as a load-bearing beam inserts into the existing masonry walls to form point connections which can minimize the destruction of the original structure. For example, in the exhibition space of the Siena il Museo Ospitale rehabilitated by Guido Canali (Figure 2-11), the elongated cable is pulled at the top of the pilasters to hang up the transparent glass exhibition cabinet or wall with help of the vertical steel cables which are fixed on the ground, forming a light and delicate touch to the old building, which also make people reminisce the lower steel rod of the traditional composite truss (Figure 1-20). For the higher indoor space, the steel truss composed by lots of steel rods can also be used as the bearing structure and reduce the height of the space. For instance, at the upper hall of the Galleria Nazionale di Parma, which is also converted by Guido Canali, the countless round steel pipes painted white are anchored together by bolts to form an entire spatial structure, the form of which is quite like a scaffold suspended and floating in the upper space (Figure 3-21, b). On one hand, it fulfills the needs of supporting the structure of the upper floor and the lighting requirements of the lower exhibition space; On the other hand, the viewer's sight is guided and focused on the lower exhibits because the structure forms a fuzzy diffusion border between the two floors. And about the craft of the connection with the brick wall, part of the original brick wall was removed to form a hole which is used to insert the end of the steel frame and fix them with the steel rod connection, to bring a reliable sense of the structure volume. Truth and illusion, heaviness and lightness, are all hidden and ablated in the old building space.

a

b

Figure 3-21: Orthogonal Steel Beam with Existing Masonry Wall (a)

La casa Liberti

(b)

Galleria Nazionale di Parma

3.1.1.4 Wood Applied to Masonry Wall This type of interfaces is usually present at the roof or beam, used to replace the original broken roof or beams made of natural wood and as a new structure supported by the existing masonry walls. At the junction, different types of steel will be used: steel brackets, embedded steel plates and steel bearings (Figure 3-23). For example, the roof of the Mercure de Sant Caterina in the old city of Barcelona rehabilitated by EMBT, the steel brackets are used to anchor the new upper cedar side beams of the roof on the existing brick walls. This type of connection makes people to think of the traditional Catalan roofs that the stone brackets on the top of the masonry walls also to support the wood beams, which is a very traditional historical interpretation (Figure 3-24,a). 69

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a

b

c

Figure 3-22: Different Crafts between Existing Masonry Wall and Interventional Wood Beam (a)

Wood Beam with Steel Bracket

(b) Wood Beam with Inserted Steel Plate (c) Wood Beam with Steel Bearing Support

a

b

c

Figure 3-24: Wood Beam with Existing Masonry Wall (a)

Mercure de Sant Caterina

(b) Residence in Munich Suburb (c)

Castello di Lichtenburg

(Building in Existing Fabric: Refurbishment, Extensions, 2003)

In the outskirts of Munich, Lydia Haack + John Höpfner extended a corridor and dining space besides a traditional masonry house through the use of the laminated wooden structure. The wood columns and beams are fixed with the inserted steel plate in the prefabricated holes and connected to the existing brick wall in the same way. After painting all the wood elements into white color, the space is much modern with a simple and consistent sense of permeability (Figure 3-24,b). While for the larger and more loaded wooden beams, some flexible joints can be applied such as what Andrea Bruno has done at the Castello di Lichtenburg. The existing brick walls are respectively as the structure supports and at the top of the lower wall with relatively concentrated vertical loads, a strip of concrete bedding is set and fixed with a rotatable metal supports connected with the upper laminated wood beams. Through this elastic connection, the variable load of the upper part is able to dissipate in the rotation of the metal bearing, greatly reducing the vibration stress to the lower brick wall. What is more interesting is that the shadow formed at the disengagement of the two parts at the interface gives the impression of a floating structure of the upper structure (Figure 3-24,c).

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3.1.1.5 Glass Applied to Masonry Wall As a structure, glass can be used in the new structure connected with the existing masonry wall through a similar bond pattern: laminated glass bonds or solid glass block bonds (Figure 3-25), to achieve visual consistency and unity.

a

b

Figure 3-25: Different Crafts between Existing Masonry Wall and Interventional Glass (a) Laminated Glass Bonds

(b) Solid Glass Block Bonds

For example, at the relics of the Magdalena Fountain in the ancient city of Hahn, CUAC inserts an all-glass stair and wall surrounded the central fountain relics as a transportation link between the main street and the backstreet due to their existing different levels. Through the bonds of the special prefabricated 3-layer laminated blue tempered glass with the transparent resin, the dark blue transparent wall and staircase is formed with horizontal lines of texture and the new wall is connected with the surrounding masonry through the angle steel. As a result, not only does the flow of water in the middle of the glass wall retain as a symbol of the past, but it also provides a deep and quiet space of memories for the lower part of the fountain enclosed with the sea-like glass (Figure 3-26, a).

a

b

Figure 3-26: Glass Wall with Existing Masonry Wall (a)

Magdalena Fountain

(b) Chanel Store

(www.dezeen.com)

The Chanel Store at the famous commercial street in Amsterdam designed by MVRDV has also fully developed the potential bearing capacity of the glass as a new kind of structure blocks. 71

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According to the size of the original structure of solid clay brick, three different widths of solid glass blocks are designed and bond with the high-strength transparent adhesive containing soy milk, forming a transparent solid crystal wall. More importantly, in order to rationally use the previous demolished bricks and form a better unified feeling with the red walls besides, some of the previous bricks are begun to be added into the glass wall masonry from the first floor and ultimately form a complete solid brick wall at the second floor similar to the previous one. This transition from transparency to thickness makes it impossible to create a new experience of weightlessness and volume digestion (Figure 3-26, b). ●3.1.2 For Reinforced Concrete Structure This kind of structures involves the wall, floor and roof, but due to the fact that most of the reinforced concrete old buildings have flat roofs, the structure of the roof can be equivalent to the floor as the same type of connecting object; Coupled with the column generally will not additionally bear loads from new structures individually, so the following will only focus on the discussion of the concrete wall and floor.

a

b

Figure 3-27: Different Crafts between Existing R.C. Wall and Interventional Steel & Wood Beam (a) Orthogonal Steel Beam

(b) Orthogonal Wood Beam

3.1.2.1 Steel Applied to Reinforced Concrete Wall The crafts of this type of interfaces are quite similar to those with the existing masonry walls, which aim to consolidate or replace the previous structure. Generally, the steel girder is distributed orthogonally on the concrete walls as a structural support for the upper slab (Figure 3-27, a). The only thing need to be paid attention is that avoiding the direct contact with the reinforcements inside the concrete wall which may result in decay and can be confirmed through the holes check or the addition of the new fillings. For example, at the entrance of the Fondazione Prada in Milano modified by OMA, a set of prefabricated I-beam girders was inserted at the top of two thick concrete walls supported with a reused riveted lattice steel column. And this steel frame structure, not only shares the upper load applied to the previous concrete walls, but also defines the flow of space and hide the lighting equipment, which highlights the industry history of the slaughterhouse in the past (Figure 3-28, a). 3.1.2.2 Wood Applied to Reinforced Concrete Wall 72

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

The same as steel, wood is also generally placed as a beam on the concrete wall, but is more suitable for supporting a roof rather than a floor due to its relatively low bearing capacity (Figure 3-27, b) And in the connection, the steel anchorage and concrete bedding are both important to retain the beam in the existing concrete wall.

a

b

Figure 3-28: Wood Beam with Existing Reinforced Concrete Wall (a)

Fondazione Prada in Milano

(b) St. Sebastian School in Munich

(http:/ www.archdaily.com)

Such as in the St. Sebastian School in Munich, since the closed concrete roof of the previous church was too depressed which was completely opposite to the requirements of an open indoor fitness environment for the students, Bolles + Wilson removed the previous concrete roof and replaced it with a series of giant glued laminated wooden beams which is wide in the middle while narrow at ends. At the position of the interface with the previous concrete walls, through the cast-in-place concrete reserved hole, the wood beam is inserted and connected in the lower part with the metal plates and screw anchorage. And the relation between the old and new is emphasized by the color differences between the new concrete ring beam covered with the white plasterboard and the previous concrete wall painted grey. Between the wood beams, in order to enhance the overall stability of the roof structure, a series of white painted steel rods are set as a linkage (Figure 3-28, b).

a

b

Figure 3-29: Different Crafts between Existing R.C. Floor and Interventional Steel & Wood (a) Ordinary Steel Column-Beam Structure

(b) Mega Steel Truss 73

(c) Wood Frame with Steel Supports

c

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3.1.2.3 Steel Applied to Reinforced Concrete Floor This type of interfaces generally occurs on the top of the concrete floor (flat roof) as a direct additive volume during the space alterations, it is because steel compared with other structural materials is much lighter and reversible for the rehabilitations. According to the size of the new volume, there are two types of crafts: ordinary column-beam steel frame and mega steel truss with supports (Figure 3-29, a&b). For example, the Münchener Rückversicherung transformed by Baumschlager + Eberle belongs to the former category. On the original concrete roof, a new glass volume is gently set and fixed with screws and steel plate between the concrete floor and circular steel columns. Since the reinforcements inside the concrete are generally arranged in lower part and side of the slabs, the new columns are set a little bit retreat to avoid the destruction of the original structure and the façade of it is not clearly perceived from the street (Figure 3-30, a).

a

b

Figure 3-30: Steel with Existing Reinforced Concrete Floor (a)

Münchener Rückversicherung

(b) Lingotto Factory

(Building in Existing Fabric: Refurbishment, Extensions, 2003)

While for the larger additional space such as the Lingotto Factory rehabilitated by Renzo Piano in Turin, a few relatively large steel bearing supports can be used directly on the concrete floor and support a large volume consisting of profiled steel trusses and a horizontal steel lattice roof. The reasonable load transferring system is presented directly through the application and expression of the steel elements, which implies the physical respect and protection for the old building, forming a dialogue between new materials in different times (Figure 3-30, b). 3.1.2.4 Wood Applied to Reinforced Concrete Floor Similar to steel, this kind of interfaces also appears on the concrete flat roof, and much more suitable for small or temporary volumes. However, due to the relatively perishable property of the wood, the best way is to add some steel elements at the connection to serve as a corresponding cushion protection (Figure 3-29, c). For example, the "parasite" hut built at the top of the elevator shaft of the Parasite Las Palmas in Rotterdam. Prefabricated impregnated glued laminated wood panels are assembled by screws on site and then bolted with the galvanized I-beam steel with the concrete bedding, forming a lightweight and solid building volume, anchored on the old building ( Figure 3-31).

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MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

Figure 3-31: Wood with Existing Reinforced Concrete Floor, the "parasite" hut (Building in Existing Fabric: Refurbishment, Extensions, 2003)

●3.1.3 For Iron or Steel Structure As the iron or steel structure is generally found in the old industrial buildings with high strength, the corresponding structural interface will normally also use steel so as to strengthen the original architectural atmosphere as well as guarantee the stability (Figure 3-32).

Figure 3-32: Craft between Existing Iron or

Figure 3-33: the Billingsgate Market

Steel Structure and Interventional Steel

(Building in Existing Fabric: Refurbishment, Extensions, 2003)

3.1.3.1 Steel Applied to Iron or Steel Column (Beam) For example, in the interior transformation of the Billingsgate Market conducted by Richard Rogers in London, in order to add a mezzanine floor in the atrium, two T-shaped steel plates are bolted at the corners of the existing giant Doric steel column and flat arch slabs and two oblique steel cables are respectively anchored on each side of the steel plates to carry the steel floor below. And below the steel slab, in order to prevent the large displacement, a series of steel trusses are fixed and anchored with the steel cables to form a similar suspended bridge mechanical system. In addition, the difference between new and old materials is identified by different color paintings (Figure 3-33).

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●3.1.4 For Wood Structure As the wood roof frame is more vulnerable to damage, generally steel with be used to improve the wood structure during the rehabilitations. 3.1.4.1 Steel Applied to Wood Roof Frame This interface is mainly based on the traditional steel-wood composite truss: the tensile chord is replaced by steel rod while compressive chord is substituted with steel profiles (Figure 3-34).

a

b

Figure 3-34: Different Crafts between Existing Wood Roof Frame and Interventional Steel (a) Steel Rods

(b) Profile Steel

Figure 3-35: Original Wood Roof Truss in Castelvecchio di Verona (http://www.archiviocarloscarpa.it/)

Among the cases of this type, the most complicated and interesting interface is the roof of Cangrande Space in Castelvecchio di Verona designed by Carlo Scarpa. From the historic photos before the rehabilitation (Figure 3-35), it was clear that the previous wood roof is composed with a series of triangular king post trusses with diagonal chords. However after the rehabilitation, the edge of the roof from the side of the old city wall becomes irregular and zigzag like a stratification of different history. As a consequence, the ordinary roof structure is also changed according to the load distribution of the roof sheet (Figure 3-36).

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MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

a

b

c

d

Figure 3-35: Craft between Existing Wood Roof Truss and Steel Elements in Castelvecchio di Verona (a)

Steel Rods for Webs & Profile Steel for Lower and Vertical Chords (c) Move Half of Upper Trusses & Rotate Lower Truss

(b) Composed with Existing Wood Beams

(d) Put Roof Sheet corresponding to Trusses Position

█ 3.2 CONSTRUCTIONAL INTERFACE According to the analysis in Section 1.2.2, these diachronic interfaces in usual cases, are located on the surface of the old structure to act as a protective or separate construction. Therefore, it includes all the detail connection positions where new cladding material is applied to the old structural material with the crafts presented through the detail sections. ●3.2.1 For Masonry Structure Like the structural interface, most of the new cladding materials act on the old masonry walls, major for covering, minor for separation. 3.2.1.1 Wood Applied to Masonry Wall This kind of wood claddings is mainly natural wood, plywood and occasional wicker, which is fixed on the masonry wall through the steel frame or keel. Thus, the cladding can both protect the inner structure as well as form a ventilation or insulation layer in-between to improve the indoor environment. At the same time, due to different function requirements, different types of cladding expressions can be achieved through the interval change of the wood panels. (Figure 3-36) For example, at the Sanierung Wohnliegenschaft in Switzerland, the red lacquered plywood boards are fixed by the steel keels onto the existing masonry walls to conceal the insulation layer (Figure 3-37, a); and at the Can Font Cultural Center transformed from a traditional Catalan residence in 77

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the small town of Barcelona, three main facades of the building are partially covered with horizontal dark wood panels as the window louvres with metal keels behind. It not only creates a certain shade and shelter for the interior space, but also formed a unified rhythm with the original facade: the horizontal metal plate is similar to the previous wall line and horizontal wood panels have similar permeability as the previous fence (Figure 3-37, b). And also on the facade of the Besucherzenrum Nationalpark Unteres in Germany, such raw materials like wickers are weaved on the metal frame with the vertical bars, bringing a rustic experience into the natural countryside (Figure 3-37, c).

a

b

c

Figure 3-36: Different Crafts between Existing Masonry Wall and Interventional Wood (a)

Woodboard with Vertical Wood Panels

(b) Woodboard with Metal Frame (c) Wicker with Metal Frame

a

b

c

Figure 3-37: Different Crafts between Existing Masonry Wall and Interventional Wood (a)

Sanierung Wohnliegenschaft

(b) Can Font Cultural Center (c) Besucherzenrum Nationalpark Unteres

(Building in Existing Fabric: Refurbishment, Extensions, 2003)

3.2.1.2 Glass Applied to Masonry Wall Glass generally requires a metal frame, a bracket or a connecting rod to be connected with a masonry wall, while for some small area with little load, glass can be directly applied to the masonry wall through the metal sheet or silicone resin (Figure 3-38). This kind of transparent material is used as a enclosure outside, not only makes the surrounding materials and the environment perception can be obtained through the reflection or transmission of sunlight, but also brings a complex experience of indoor and outdoor scenes form a continuous sight from the inside to the outside; While regarded as a separation inside, can also be combined with the use of light and space to create a unique special atmosphere. For example, in Centro Fieristico le Ciminiere, Giacomo Leone transformed many old industrial houses made of lava stones and red bricks into several independent office spaces for a new cultural 78

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centre. Through the protruding horizontal windows with steel frames on the original façade of the first floor, the previous industrial temperament is strengthened and the glass reflection also provides the vague image of the chimney for the viewers on the street like a realistic illusion (Figure 3-39, a). And for the need of a glass surface to carry a larger wind load, a steel rear rod system can be introduced to solve the problem. For example, at the top of the cross section of Manica Lunga of Rivoli Art Museum, in order to completely observe the opposite view of the old castle facade, Andrea Bruno glued six large glass plates together and set a series of steel rods at the two connecting points in the middle of the glasses (Figure 3-39, b). On the other hand, for those positions with less loads and smaller sizes, the glass can be fastened by small metal clamps or glued to the masonry walls, such as in the Palazzo Bianco, Franco Albini only used silicone resin and metal clamps to enclose the irregular apertures of the Loggia, which forms almost completely transparent glass surface (Figure 3-39, c).

a

b

c

Figure 3-38: Different Crafts between Existing Masonry Wall and Interventional Glass 1 (a)

Steel Frame

(b) Pointed-support Steel Rods

a

(c) Metal Clamps and Binder

b

c

Figure 3-37: Different Crafts between Existing Masonry Wall and Interventional Glass 1 (a)Centro Fieristico le Ciminiere

(b) Manica Lunga of Rivoli Art Museum (c) Palazzo Bianco

In addition, the glass will be often found in the courtyard as a transparent roof cover, or at portion of the interior floor as a skylight, connecting with the surrounding masonry walls with the help of the steel frame (Figure 3-40). For smaller glass roofs, they are usually connected with the masonry walls through the steel panels inserting, at the entrance of the Madrid History Museum, the glass skylight between the new roof and the old masonry walls is inserted into the holes pre-set in the masonry wall with steel girder 79

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below and sealed by filling the elastic waterproof material (Figure 3-41, a). There are also some translucent glass slabs fixed and connected by steel frames that can be illuminated by the internal light to achieve a special effect of the masonry wall, such as a circular floor in the underground of the Siena il Museo Ospitale (Figure 3-41, b). For a large span of roof cover, an integral steel frame is secured by providing a concrete ring beam at the top of the masonry wall. One of the most classic cases is the huge roof in the courtyard of the British Museum invented by Norman Foster in London, by adding the concrete beams and columns at the top of the original brick walls and fixing steel column and beam on them, a variety of triangular glass plates with steel frames are connected from the middle to the side walls and the seam of the interface is just worked as a ventilation opening (Figure 3-41, c).

a

b

c

Figure 3-38: Different Crafts between Existing Masonry Wall and Interventional Glass 2 (a)

Inserted Steel Beam

(b) Nailed Steel Beam

a

(c) Steel Frame with Concrete Bedding

b

c

Figure 3-39: Different Crafts between Existing Masonry Wall and Interventional Glass 2 (a)

Madrid History Museum

(b) Siena il Museo Ospitale

(c) the British Museum

3.2.1.3 Stone Applied to Masonry Wall Due to the diversity of the stone, when it connects with the masonry wall, there are a lot of different crafts that can be used: slate with mortar bonding or metal dry hanging, gravel pavement, plaster and plasterboard stud (Figure 3-40). These stone claddings, on one hand protect the original masonry wall, on the other hand presents historical stratification from colors and textures. First of all, about the slate, when it is used on the external wall, the best choice is the stone with a better anti-corrosion and a certain degree of hardness. The adhesive mortar needs to have a certain permeability and flexibility, and a certain gap should be left between the slates to allow certain deformation or damage caused by temperature change. For example, in the Corte Interna 80

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

all'isolatoai Bottari project in Siracusa rehabilitated by Vincenzo Latina, a new wall made up of the scrap slabs, golden yellow sandstones and Cyclopean concrete was built in front of an old rubble wall (Figure 3-41). Through the use of back mortar and horizontal seams, new stone slates are fixed to the old one with a natural horizontal and vertical separation lines; Furthermore, since the size and color of each stone slate is not the same, the surface formed after layers of stacking makes people to reminisce an original ancient Roman dry stone masonry process --- Opus Quadratum, while the natural cut surface shows a different texture from the lower part of the wall which is composed with the remaining stone slates and surrounding mottled wall, exuding a charming and sincere history flavor under the warm sunshine of Sicily,.

a

b

c

d

e

Figure 3-40: Different Crafts between Existing Masonry Wall and Interventional Stone (a) Metal Dry Hanging (b) Bond with Mortar

(c) Gravel Pavement

(d) Plaster

(e) Plasterboard Stud

Figure 3-41: Stone Slate Bond with Mortar with Existing Masonry Wall, Corte Interna all'isolatoai Bottari (http://www.divisare.com)

In the Museo Arqueologico, the original building stone base is set as the new sunken entrance where three doorways were dug from the original positions of the window holes and covered with dark grey soapstone slates which were supported on the original wall with metal anchorage behind. 81

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Due to the necessary needs of the museum, the automatic glass sliding door and light device are concealed inside the vacant in-between space of the interface which also presents a simple and clean overall effect on the facade (Figure 3-42, a).

a

b

Figure 3-42: Stone Slate Applied to Existing Masonry Wall (a)

Museo Arqueologico

Figure 3-43: Gravel Pavement Applied to Existing Masonry Walls Upper: Museo Nazionale delle Arti del XXI Secolo Lower: a toy library and office next to the Basilica of Santa Maria del Pi

(b) Fondazione Querini Stampalia

About the interior cladding, the available types and surface treatments of the stone slates are richer and mostly connect to the masonry walls directly, such as the new cladding in the Fondazione Querini Stampalia. The new cladding consisting of travertine slabs, limestones and aggregate concrete are bonded to the existing masonry wall with mortar. The lower part of the wall composed of limestone and aggregate concrete extends to the floor, play a role in protecting the wall as well as make the space continuous, while the upper part of the wall composed of the travertine slates are separated in the middle by an embedded copper horizontal strip the height of which is designed for hanging exhibitions like paintings. In addition, in some vertical gaps between the travertine panels, the translucent glasses embedded lamp vessel are introduced, forming a continuation of the strips of the interior space, which helps to elongate the exhibition space between the canal and the garden and becomes a metaphor of the water in this context (Figure 3-42, b). Secondly, about gravel pavement, it is generally used for outdoor flooring, especially at the border between the old building masonry wall and the new pavement, forming a buffered softening interface and hiding drainage or other constructions. For example, in a toy library and office next to the Basilica of Santa Maria del Pi in Barcelona and the expansion of the Museo Nazionale delle Arti del XXI Secolo (Figure 3-43), whether it is the new cement pavement or traditional slate pavement, both keep a distance off the masonry 82

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

walls of the old buildings and insert a scattered white cobble bedding between them, which protects the original wall from man-made damage and produces a kind of monument-like feeling towards the old buildings.

a

b

Figure 3-44: Plaster Applied to Existing Masonry Wall (a) Palazzo Madama

(b) Casa dell'androne e cortile

Then, about the plaster, in general the key parts of the masonry wall will be retained and exposed. Especially for those walls with some important structural components in irregular shapes, the plastic plaster is more convenient compared to other stone construction. For example, in a traffic space in the Palazzo Madama at the center of Turin (Figure 3-44, a), in order to highlight the only remaining Fibellona Gate in Turin's medieval expansion, the left part of the masonry walls are all painted with a smooth layer of plaster to emphasize the brick texture of the relics; While at the entrance of Casa dell'androne e cortile at the rear of the Catania Amphitheatre (Figure 3-44, b), the history evolution of the masonry walls is manifested through plasters in different colors: the unfinished factory wall built in the 18th century was painted with ocher plaster while the shop wall of the mezzanine in the 19th century was covered with white plaster. In addition, the original wall pier and corners with volcanic rock masonry are remained and exposed, which have a strong contrast with the plaster as if telling a vivid historical story through the materials.

Figure 3-45: Plasterboard Applied to Existing Masonry Wall, Museo dell'Opera del Duomo

Finally, compared to the traditional handicraft plaster which requires much labor, large quantities of more regular space (especially large museum exhibits), in recent years choose to use plasterboard or cement fibre board to cover the masonry wall of the old buildings because the prefabrication process in the factory is more rapid and easy to be removed. These artificial stone boards can be fixed on the surface of the masonry wall by steel or wood studs (due to the hardness is not so high, it is not suitable for the facade), and the gap inside the studs can be filled with insulation materials to improve building performance. For example, in the Museo dell'Opera del Duomo transformed by Adolfo Natalini, the plasterboards of different colors are used in many 83

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locations of the exhibition hall to foil the space and exhibits: at one side of the entrance corridor, a quite long dark grey plasterboard is divided in the middle by a series of vertical light grey limestone slates engraved with all the names of the historical figures involved in the cathedral building project; At the high center of the exhibition hall, the counterfeit of the cathedral facade is erected made of gypsum in a warm color while the cold grey plasterboard is set as a background of the façade to differentiate; at the side exhibition space on the first floor, the original marble panels from the Bell tower are hung in two rows on a layer of brown plasterboards the size of which is corresponding with the exhibits to form a rigorous and orderly rhythm (Figure 3-45). 3.2.1.4 Metal Applied to Masonry Wall When a metal sheet connects with the masonry wall, normally the same type of metal rivets will be used (to prevent corrosion between different metals) directly as the anchorage. Usually the positions of these interfaces are part of roofs, walls or openings (Figure 3-46), to prevent the visual encroachment and interference of the old masonry wall caused by large area use of metal.

a

b

c

Figure 3-46: Different Crafts between Existing Masonry Wall and Interventional Metal (a) Inserted Rivets

(b) Exposed Screws

(c) Hidden Welded Anchorage

Among them, copper, aluminum and zinc sheets are generally used as roofing or sealing strips to prevent water. Such as the roof of the Church of Santa Maria in Cazorla renovated by Pedro Salmerón Escobar and the top sides of all the old brick walls of the Rivoli Art Museum, both are covered by the copper sheets and added with a vertical flange at the edges of the sheet to avoid rainwater dripping along the old masonry wall as well as create a similar brick-like architrave ( Figure 3-47, a&b); While in the Mercat de Sant Caterina directed by EMBT (EnricMiralles + Benedetta Tagliabue), an aluminum strip was inserted between the original masonry wall and the new composite roof structure as a weatherstrip to achieve the basic requirements of waterproof and bring a solid sense of consistency with the original bricks (Figure 3-47, c). Besides, weathering, galvanized and stainless steel sheets are more widely used as a cover protection of walls and apertures. For instance, in the Alemany 5 hostel renovated by Anna Noguera, all the edges of the doors and windows on the existing stone walls are wrapped in a layer of weathering steel plates, emphasizing the sense of different materials; And the smooth dark brown steel plate also provides a visual link with the existing dark wood elements and warmly-yellow stones in the old building, which inherits the historical features of the Spanish districts (Figure 3-48, a); in the Museo Arqueologico transformed by Frade Arquitectos, all the arch doors appearing in the exhibition circulation are covered with a layer of galvanized steel, 84

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

which consolidate the old masonry structure and emphasize the existence and solidity of the wall (Figure 3-48, b); In the Caixa Forum de Madrid rehabilitated by Herzog + de Meuron, although a layer of stainless steel plate has almost covered all the elements on the ground floor (ceiling, columns), because of the retreat and dimension reduction of the vertical structure, the shadow above can totally obscure or even conceal these eye-catching materials (Figure 3-48, c). Thus, there is only a long but thin strip of steel firmly fixed on the bottom of the old brick wall in the final appearance of the building, which completely disintegrates the original masonry wall from the ground and brings the viewer a distorted weightless experience.

a

b

c

Figure 3-47: Metal Applied to Existing Masonry Wall (a) Church of Santa Maria in Cazorla

(b) Rivoli Art Museum

a

(c) Mercat de Sant Caterina

b

c

Figure 3-48: Metal Applied to Existing Masonry Wall (a) Alemany 5 Hostel

(b) Museo Arqueologico

(c) Caixa Forum de Madrid

3.2.1.5 Plastic Applied to Masonry Wall Since the history of plastic to be applied in the rehabilitation isn’t quite long, coupled with its slightly modern shape and texture, generally it is more difficult to form such a coherent visual unity with old materials like masonry and consequently less appear in the diachronic interface. Only the transparent film material, which is gradually replacing the glass, begins to appear in the roof position of the old masonry building due to its more lightweight characteristics and it can be connected with metal elements (Figure 3-49). For example, in the S. Pere Church in Poble Vell de Corbera d'Ebre, owing to the war, the original roof has been completely destroyed, so on the existing masonry wall of the church, an ETFE film is used as a transparent ceiling supported by the steel frame covering the lower space. The slender steel rods are anchored by bolts and each of the plastic film is nailed on the curved steel rods and anchored to the vertical steel rafters; At the end of the roof of each steel rafter, a steel slumped outfall is screwed as if a claw firmly grasps on the edge of the cornice on the façade (Figure 3-50). 85

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Figure 3-49: Craft between Existing

Figure 3-50: Craft between Existing Masonry Wall and Interventional

Masonry Wall and Interventional

Plastic, S. Pere Church in Poble Vell de Corbera d'Ebre

Plastic

(Restauración de la Antigua iglesia de Corbera d’Ebre, 2011)

●3.2.2 For Reinforced Concrete Structure The old structures of this kind of constructional interfaces are mainly floors and walls (as in Section 3.1.2), usually covered by the surface cladding, and it is also necessary to avoid the damage to the internal reinforcement of the original structure. 3.2.2.1 Wood Applied to Reinforced Concrete Floor The constructional interface between wood and concrete is similar to that with masonry, which is connected through steel or wood studs maybe filled with insulation materials. Wood is mainly used as an interior cladding material (especially synthetic wood) while less used on the facade because of the durability (Figure 3-51), such as the wood flooring in the Siena il Museo Ospitale, (Figure 3-52, a).

a

b

Figure 3-51: Different Crafts between Existing R.C. Floor and Interventional Wood (a) Nailed with Wood Stud (b) Bolted with Profile Steel

a

b

Figure 3-52: Wood Applied to Existing R.C. Floor (a) Siena il Museo Ospitale

(b) Münchener Rückversicherung 86

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

For the multi-storey or high-rise buildings with large plans, sometimes the wood flooring will also connect to the existing concrete floor with flexible steel point supports so as to achieve good structural seismic resistance, such as the birch and maple plywood claddings erected on the concrete slabs in Münchener Rückversicherung, which also provide a warm and comfortable working atmosphere for the indoor office space (Figure 3-52, b). 3.2.2.2 Glass Applied to Reinforced Concrete Floor & Wall The most common of these interfaces are the additional glass curtain walls adjacent to the existing concrete wall and the glass roofs on the top of the concrete wall connected with the steel studs or other steel elements (Figure 3-53, a & b).

a

b

c

Figure 3-53: Different Crafts between Existing R.C. Wall (Floor) and Interventional Glass (a) Glass Curtain Wall with Steel Studs (b) Glass Roof with Steel Girder (c) Glass Slab with Steel Frame

In addition, for some display spaces below the concrete floor (especially the historical underground space), the reinforced concrete floor can be partially dismantled and substituted with glass to get the sight contact (Figure 3-53, c) For example, at the end of the gallery on the ground floor of the Museo dell'Opera del Duomo, there is a very large glass window on the ground showing the 16th century spina-pesce masonry structure underground; similar glass slab is also found in the Castelvecchio di Verona and the Siena il Museo Ospitale, which is inserted into the concrete floor to let the visitor take a close look or even stand on to feel the historical space underneath (Figure 3-54).

a

b

Figure 3-54: Glass Applied to Existing R.C. Floor (a) Museo dell'Opera del Duomo

(b) Castelvecchio di Verona

3.2.2.3 Stone Applied to Reinforced Concrete Floor & Wall 87

(c) Siena il Museo Ospitale

c

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Similar as the interfaces with the masonry, there are also lots of different crafts between existing reinforced concrete and stone such as slate with metal dry hanging, gravel pavement and plasterboard studs (Figure 3-55, a, b & c).

a

b

d

c

e

Figure 3-55: Different Crafts between Existing R.C. Wall (Floor) and Interventional Stone (a) Slate with Metal Dry Hanging (b) Gravel Pavement (c) Plasterboard with Studs (d) Plasterboard with Metal Suspension (e) Terrazzo with Metal Strips

For example, in the Münchener Rückversicherung, the dolomite plate is fixed to the both sides of the reinforced concrete wall by means of steel brackets and anchors. Especially on the facade as a windowsill, open oblique notches are set to insert external glass for vertical ventilation and rhythm change (Figure 3-56, a); And in the Topographie des Terrors in Berlin, at a certain distance from the old reinforced concrete wall, a long corridor is paved with square stones for visitors to walk through where the existence of the relics is only covered with some gravels, forming a width variation of the pavement. At the same time, the thin layer of deep gray gravel on the original concrete base, not only achieves the aim of "watching far away but not dallying nearby" towards the relics, but also contrast the Nazi past traces of the depressed atmosphere (Figure 3-56, b).

a

b

Figure 3-56: Stone Applied to Existing R.C. Wall (a) Münchener Rückversicherung

(b) Topographie des Terrors

In addition, for the floor parts, plasterboard suspended under the ceiling and terrazzo paving with metal strips (Figure 3-55, d & e) can also be used to create a special space atmosphere. For example, at the medieval exhibition space in the Museu Nacional d'Art de Catalunya designed 88

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by Gae Aulenti + Enric Steegmann, there is a group of delicately designed plasterboard ceiling covered underneath a reinforced concrete coffering floor. Firstly, a specially designed V-shaped steel frame is anchored with the sub-beams orthogonal to the main beams, which is used to conceal the ceiling lightings; Then two white plasterboards are inserted into the edges of the steel frame and converged in the middle with a steel rod which is acted as the light hanging track; And at the position where the plasterboard meets the main beam, a slightly enlarged opening forms and achieve a plug-in anchoring effect; Finally the hanging ceiling above the exhibition space appears to be pure and with a classical decorative atmosphere and forms a harmonious unification with the multi-layer concave plaster moulding in terms of scale and shadow (Figure 3-57, a). While for the ground of the coffee bar in the Fondazione Prada in Milano, the terrazzo with red Verona sedimentary rock powder and gravel makes the original slightly cold industrial concrete space have a little warm quaint color, and compiled with the dark wood and the retro wallpaper of the last century, creating a similar movie scene of elegant atmosphere in the classic American coffee bar; And the same use of terrazzo paving on the ground at the doorway between different exhibition rooms in the Neues Museum, also works like a transition and limitation of space with a light blue square mosaic pavement (Figure 3-57, b&c).

a

b

Figure 3-57: Stone Applied to Existing R.C. Wall (a) Museu Nacional d'Art de Catalunya

(b) Fondazione Prada in Milano

(c) Neues Museum

3.2.2.4 Metal Applied to Reinforced Concrete Wall Compared with the masonry wall, the crafts to be used between metal and existing reinforced concrete are much more abundant and innovative with larger dimension. In addition to the traditional use of rivets for anchorage, there are also back studs and gold gilding (Figure 3-58).

a

b

Figure 3-58: Different Crafts between Existing R.C. Wall and Interventional Metal (a) Exposed Rivets Anchorage (b) Back Steel Studs 89

(c) Gold Gilding with Mortar

c

CHAPTER 3 INTERVENTIONAL CRAFTS

Such as on the facade of the Alf Lechner Museum, Alucobond Panel is used and connected to the original reinforced concrete wall by aluminum rivets and vertical tendons at the seams. Due to the existence of 25cm ventilation cavity between the aluminum plate and the original wall, the rain pipes on both sides of the roof skylight can be effectively hidden inside. And corresponding to the location of the internal windows and vents, the perforated aluminum plates are used to make the building volume will not be destroyed by the functional requirements (Figure 3-59, a). And on the east facade of the Podium in Fondazione Prada, a vertical mirror stainless steel sheet is used to cover the original industrial plant section after dismantlement. The roughness of the original reinforced concrete wall and the smoothness of the stainless steel plate strengthen the independence of the surface layer and it is highlighted through the precise fit to the corner cornice which seems to be the best interpretation of the historical changes; And if watch the cladding layer from a certain distance, the real space images will always mirror and present on it as if engraving old history, as if creating new birth, which perfect fits the concept of fracture and continuity to be conveyed by Rem Koolhass (Figure 3-59, b). In the same rehabilitation complex, all the external walls of the Haunted House in Fondazione Prada are treated as follows: firstly, a layer of reddish brown terracotta lime mortar (cocciopesto) is painted from top to bottom on the original reinforced concrete wall as a base; then pieces of small gold foil are stuck on with a hand roller which is along the horizontal direction to ensure that there is no gap between the gold foil; finally, the hair dryer is used to blow away the gold foil powder off the surface, forming a tight and smooth glossy cladding, which completely and vividly conveys the "permanent monument" concept with the special material (Figure 3-59, c).

a

b

Figure 3-59: Metal Applied to Existing R.C. Wall (a) Alf Lechner Museum (b) (c) Fondazione Prada in Milano (Building in Existing Fabric: Refurbishment, Extensions, 2003)

3.2.2.5 Plastic Applied to Reinforced Concrete Wall In view of the short history of plastic development, such interface is quite rare, but only as a translucent wall partition connected with the old concrete wall through the metal frame (Figure 3-60). For example, also in the Fondazione Prada in Milano, many partition walls are made of PC Multiwall Sheet to achieve a translucent effect as well as have a better acoustical and thermal insulation performance (Figure 3-61).

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MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

Figure 3-60: Craft between Existing

Figure 3-61: Craft between ExistingR.C. Wall and Interventional Plastic,

R.C. Wall and Interventional Plastic

Fondazione Prada in Milano

●3.2.3 For Iron or Steel Structure 3.2.3.1 Glass Applied to Iron or Steel Column (Beam) Since iron or steel structures are generally found in old industrial buildings which require better lighting, the corresponding constructional interfaces (such as enclosure) are generally made of glass which is fixed to the original beams or columns by means of steel frames (Figure. 3-62). Such as in the high atrium space of the Tate Modern rehabilitated by Herzog & de Meuron, a few new space volumes wrapped with sandblasted glass are set directly on the original large steel riveted-composite box columns by bolts and some welded bars are used to connect the peripheral glass plate. So the translucent volumes formed are just like some new lives growing on the original steel structure, firmly leaning on and embellishing the atrium space through the internal distribution of the uniform lighting (Figure 3-63).

Figure 3-62: Craft between Existing Iron

Figure 3-63: Craft between Existing Iron or Steel Structure and Interventional

or Steel Structure and Interventional

Glass, Tate Modern

Glass

(https://www.herzogdemeuron.com)

●3.2.4 For Wood Structure 3.2.4.1 Stone Applied to Wood Roof Frame In some higher interior spaces, in order to solve the distributing problem of heating and lighting pipelines without breaking the space entirety, sometimes the plasterboard ceiling will be added 91

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below the roof structure (Figure 3-64). For example, in the high exhibition hall of the Museo dell’Opera del Duomo, a group of ceiling box made of long plasterboards is suspended underneath the previous wood roof trusses: both sides of the solid parts conceal the huge ventilation ducts and the groove steel at the bottom edges is acted as the track for spotlight; and the middle part is strengthened by the plasterboard ribs distributing at a certain interval, forming a group of filtering light gaps in the overall ceiling (Figure 3-65).

Figure 3-64: Craft between Existing Wood Roof Frame and Interventional

Figure 3-65: Stone Applied to Existing

Stone

Wood Roof, Museo dell’Opera del Duomo

█ 3.3 CONFIGURATIONAL INTERFACE According to the analysis in Section 1.2.3, this kind of diachronic interfaces usually appears in the connection between the existing building and the extension volume. Thus, it is the use of the new interventional material applied to the corresponding old existing cladding material (including the structural material with the cladding property, such as masonry) which can be more intuitively reflected through the elevations. ●3.3.1 For Masonry Surface

a

b

c

Figure 3-66: Different Crafts between Existing Masonry Surface and Interventional Materials (a) Face Brick Staked with Steel Rods

(b) Weathering Steel Plate Anchored with Studs

(c) Printing Glass Prefabricated

Since the masonry surface has a certain pattern of textures and sizes, the interventional materials to be used for connecting will also be of a similar modular textures, such as brick, modular glass and metal panels; and in order to achieve the varied colors and rhythm as those in the original 92

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

handmade masonry, the characteristics of new interventional materials will be fully discovered and applied to obtain the unity and coherence of the visual texture. Thus, the following is a detailed analysis of three examples of related interfaces designed by Herzog & de Mellon to further explain different interventional materials and crafts for the existing masonry surface (Figure 3-66). 3.3.1.1 Brick Applied to Masonry Surface Due to the heavy weight of the brick, this type of configurational interfaces generally exists in the horizontal extension of the old building and the new structure volume is covered with facial bricks to achieve the echo from the brick texture of the old building. For example, the New Tate Modern which looks like a tiled brick tower integrated with the original power station is actually a totally new reinforced concrete building. However, it is still full of new craft inspiration despite of the visual harmony. The brick wall used as the surface layer, is in fact composed of each unit consisting of two or four bricks (T-shape) and bonded with mortar; While in the overall brick facade, quite different from the past, all the brick units are stacked with the vertical steel rods inserted through the pre-set holes at the ends of the bricks. Eventually, in the overall relationship, the new façade forms similar astringent shadows and lines with the old building without any exposed concrete contrast and abruption in the original scheme. Because of the response of the new material craft to the old building on the design language and configuration level, these two are closely connected and integrated in differences (Figure 3-67)

Figure 3-67: Brick Applied to Existing Masonry Surface, New Tate Modern (https://www.herzogdemeuron.com)

3.3.1.2 Metal Applied to Masonry Surface Compared to the heavy bricks, the lightweight metal panel is more suitable for some vertical extension of the old building, especially the reddish brown weathering steel plate, achieving a perfect unity with the original masonry in color and texture. On the facade of the Caixa Forum de Madrid, the extension facade above the old brick wall is supported by the rear steel structure which makes the weathering steel surface aligned with the old brick wall. These plates, not only corrode gradually with the external air oxidation and show some rust on the surface, but also leave different shades of dark red marks under the rain washing which echoes with the mottled texture of the original brick wall below; Furthermore, the size and position of each steel plate also follows the rhythm of the original window of the old brick wall, forming a unified visual coherence (Figure 3-68).

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Figure 3-68: Metal Applied to Existing Masonry Surface, Caixa Forum de Madrid (https://www.herzogdemeuron.com)

3.3.1.3 Glass Applied to Masonry Surface The more prestigious prefabricated glass is also used as a cladding material for the vertical extension of the old building, which achieves the echo of the original masonry from the rhythm of the transparency and surface bump changes. The top extension of the Elbphiharmonie Hamburg located on the banks of the Elbe, not only continues the contours of the original masonry walls and a certain proportion and scale of the material (the new window glass partition is based on the size of the original window aperture), but also echoes the small-scale window openings of the original thick masonry facade in an interpretation way of the new material crafts. First is the use of prefabricated surface mold pouring to form two types of special facade openings: one is the semi-elliptical aluminum frame openings similar to the traditional windows, the other is a corrugated variants of modern double-layer glass forming ventilation inside, which together create a three-dimensional facade changes; Second, in order to form a unit change in the rest parts without natural ventilation, many ordinary flat glass are printed with the spray of the glazed points, forming an oval transparent gradient. These white spots, which are concentrated in the periphery and gradually reduced to the center, like the background borders of dream, putting the external scenery into the clouds and dispersing the interior of the light and shadow into the hazy stars (Figure 3-69).

Figure 3-69: Glass Applied to Existing Masonry Surface, Elbphiharmonie Hamburg (A Crystal in the Harbour–The Glass Façade of the Elbphiharmonie, 2010)

●3.3.2 For Plaster Surface Compared to the masonry surface with its own size, the plaster is not very eye-catching and sense of presence, but more like an unknown background foil, can only be aware of through some local 94

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

openings or decorative changes. Therefore, when dealing with it, more primitive and simple cladding materials, such as concrete and stone, will be used to make the overall facade look more harmonious and unified; And some bump changes on the façade with light and shadow will also provide a continuation between the old and new. Among them, the two cases designed by Carlo Scarp in Verona are the most intriguing ones, which separately use concrete and stone to deal with the original plaster surface and achieve the complementary and definition with the original material through some margin lines left blank or wrapped by other materials (Figure 3-70).

a

b

c

Figure 3-70: Different Crafts between Existing Plaster Surface and Interventional Materials (a) Exposed Concrete with Steel Strip

(b) Plaster with Slate Strip

(c) Slate Bond with Mortar

a

b

c Figure 3-71: Stone Applied to Existing Plaster Surface, Historical Changes of Façade of Caserma in Castelvecchio di Verona (a) Hypothesis Façade in 1806 (b) Hypothesis Façade in 1923 (c) Façade after 1958 95

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3.3.2.1 Concrete Applied to Plaster Surface In the Castelvecchio di Verona, there is a space in-between created by Scarpa which is formed by the old city wall and the cross section of Caserma. According to historical photographs and corresponding documents, the original facade including this space was firstly built in 1806, in the Napoleonic style. Later in 1923 under historical intervention conducted by Antonio Avena and Forlatti, it was transformed into the assumed Gothic style. Thus, when it turned to Scarpa in 1958, he planned to open a historical stratification space by removing the existing staircase and portion of the Caserma’s facade, which became the semi-outdoor space for placing the Statue of Cangrande (Figure 3-71). And as the most prominent interface to present historical evolution of the old building, Scarpa removed the edge of the wall regularly which formed a zigzag periphery of the cross section of the wall; And then during the design of a new concrete wall (actually used to support the upper steel column and roof structure), he set a vertical channel steel in between to indicate and highlight a new layer of the old building. As a result, during the fine weather when the warm sunlight shines on this facade, these few vertical gaps fell into the shadow as if telling the changing history of the existence. 3.3.2.2 Stone Applied to Plaster Surface

Figure 3-72: Stone Applied to Existing Plaster Surface, Verona Banco Popolare (Time, Space & Material : The Mechanics of Layering in Architecture, 2015)

The façade of Verona Banco Popolare is a reflection of the right material selection and craft practices in the old town centre. Adjacent to it is an existing bank facade in a typical Renaissance three-section plaster surface: the upper two floors are the traditional Italian plaster in light yellow while the bottom is made of the plaster imitating the texture of ashlar stone masonry. Each section is separated by white horizontal plaster feet and at the corner of the wall to contact with the new façade a round chamfer is formed accompanied with a vertical seam which seems like a three-story angle column. In order to enhance the segmentation features along horizontal direction, Scarpa used different materials in each section to form its own characteristics of the three-section façade: white marble plate collage is used at the bottom as an echo with the stone-like texture plaster; light red Venetian plaster is selected as the cladding for two middle floors and at the edge with a linear white marble plate for protection, which also results in a similar linear contour with the traditional doors and windows; the top floor is formed with retreated steel columns to bring the shadow for the transparent glass facade. In order to further respond to the adjacent facade, between the bottom and the middle floor, a thick strip made of multi-storey concave frame is introduced with the use of Verona region prolific red marble stitching, forming a very similar effect of light and shadow with the old building at the same level; Furthermore, the vertical steel 96

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

column at the connecting position between the old and new façade also shows a humble slim attitude compared with the thick plaster corner column, as a traditional continuation and transmission (Figure 3-72). ●3.3.3 For Glass Surface Since the glass in the old building is generally the wall openings (such as doors and windows) and mostly is made up of small pieces with a frame due to the limited crafts at that time, in order to improve the performance after the rehabilitation, most of the glass is replaced by new insulation glass with larger size, and only a small part of distinctive or important glass is retained and protected through the new glass cladding (Figure 3-73).

a

b

Figure 3-73: Different Crafts between Existing Glass Surface and Interventional Glass (a) Glass Fixed in Metal Frame

(b) Glass Glued together and Point-Supported by Steel Rods

3.3.3.1 Glass Applied to Glass Surface For example, the vertical strip glass pane on the facade of Tate Modern Museum is the most common type of veneer glass in the early 20th century. By setting a large, long-facing double-glazed glass and steel frame inside it, the protection and internal insulation performance as well as the original experience of the steel-frame glass window are all satisfied (Figure 3-74, a). And at the ruins of the Grand Hotel Esplanade in Sony Center, some tempering glass boxes are also used to protect and present the original doors and windows through the rear steel frame and point supports the glass of which is also arranged according to the old proportions (Figure 3-74, b ).

a Figure 3-74: Glass Applied to Existing Glass Surface (a) Tate Modern Museum (b) the Grand Hotel Esplanade in Sony Center (Building in Existing Fabric: Refurbishment, Extensions, 2003)

97

b

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●3.3.4 For Ceramic Roof Tile Surface In the transformation of the roof, in order to reduce the unnecessary load on it, a light metal panel such as copper plate is better to be used as a replacing or additional roofing material (Figure 3-75).

Figure 3-75: Craft between Existing

Figure 3-76: Metal Applied to Existing Ceramic Roof Tile,

Ceramic Roof Tile and

Castelvecchio di Verona

Interventional Metal

3.3.4.1 Metal Applied to Ceramic Roof Tile Surface The most prominent example of this type is also from the Castelvecchio di Verona. From the elevations in Figures 3-71, c, it is seen that after the removal of the large staircase, rear wall and roof adjacent to the old city wall, a more lightweight zigzag copper roofing is supported by the steel-wood composite roof trusses (Figure 3-35). The copper rivets of the new roof used to anchor the plates forms quantity of horizontal lines which has a similar texture and rhythm with the original ceramic tiles; and the natural height difference created by the different thickness of roofing materials makes the new part of some new branches growing out of the original roof which still maintain a consistent texture with the old part (Figure 3-76). All the outcomes about this chapter have been summarized in the Appendix 1.

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99

CHAPTER 04 DESIGN METHODS FOR DIACHRONIC INTERFACES

CHAPTER 4 DESIGN METHODS

█ 4.1 GENERAL PRINCIPLES After discussing and studying of quite a few splendid rehabilitation cases in Western Europe above, there seems to be a much clearer and more explicit understanding about what a good diachronic interface, or rather, a “Correct” 26one is. As a result, it can be summarized and induced into several general design principles of diachronic interface for materials and crafts, which will be the principal ideas to be followed during the design process. ●4.1.1 APPROPRIATE MATERIAL UTILIZATION First of all, in terms of diachronic interface, the most direct and specific concern absolutely comes from the interventional materials themselves, namely the thought on the physical extent which is just like the most fundamental requirement “Firmness” that Vitruvius Pollio identified in three elements necessary for a well-designed building. Thus, “Durability” is the overarching criterion for judging whether the material is appropriate or not. In fact, this does not only include the physical performances of the interventional materials such as strength or anticorrosion, but also needs to take into consideration the physical or chemical interaction between the previous materials and interventional ones. Secondly, such requirements like “Reversibility”, “Lightness” and “Environmental-friendliness” are the standard criteria that the interventional materials should qualify for. However, these are not static concepts under the sustainable society and technology development which are changing all the time. From iron rivets in the early 1900s to steel bolts in the second half of the 20th century, transparent glasses have been partly substituted for ETFE Membrane, as well as a large number of natural wood cuttings have been proceeded into laminate or plywood. Therefore, “Appropriate” materials are dynamic and developing which depend on the specific eras and society. In addition, “Appropriate” also reflects on “Local Adaptation” of the materials. For instance, glittering and magnificent architectural decorations are made from various stones in Italy; cozy and warm wood villas are embellished among vast forests in Switzerland; light and huge long-span structures spring up with the steel production in Britain industrial cities. All of these buildings are created through the local material resources which in turns give the cities or even the landscapes peculiar features forming the local history and culture. ●4.1.2 HARMONIOUS RELATION EXPRESSION Although the design of the diachronic interface is mainly the selection of interventional materials, the real standard to decide whether it is good or not is grasp how to present a harmonious relationship between old and new. In other words, the “Harmony” does not mean to sacrifice any portion of the object: the interventional part neither overwhelms the previous portion to underline its delicate difference nor yields to the previous one to present its rigid deference. Thence, in my opinion, the state of “Harmonious” relation should be “neither Humble nor Pushy”but “Attractive”. When watching it from a far distance, nothing special or weird will immediately occur. However, once moving forward, the things that gradually come into view are 26

According to Luigi Nervi, the evaluation standards for “building in a correct way” includes: the materials and techniques used on condition of a fixed time and site, the material utilization according to its property, the structure features derived from ancient buildings and emotional intuition and sensitivity. Thus, it seems to be quite consistent with author’s attitude towards the diachronic interface design. 102

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quite temperamentally different. After savoring them carefully, specific imagination and meanings will appear naturally and enlighten viewers. Thus, this kind of sensual experience is bound to be advanced step by step. Although it needs the activeness and perception from the viewers, the more significant thing is how the designer manages the key of the relation through crafty design. Consequently, when it applies to different types of diachronic interfaces, there will be corresponding design rules and features. For Structural Interface, the harmonious relation lies in the incorporation of “Reasonable Stressing” Structure and “Light-footed” Impression. No matter steel structureinserts into the previous hollow brick wall, or glass bricks bond together to support the previous brick wall, they both integrate force and beauty, which deduce a reasonable-light structure on the premise of guarantee the minimum damage of the previous materials and crafts. For Constructional Interface, the harmonious relation is determined by the perfect superposition of “Reversible” and “Rigorous”. Whatever the board nails for surface protection or the glass implant for insulation enclosure, the delicate consideration and design of every single detail does not only establish on the care and respect for the previous materials and crafts, but also explain the adjusting and optimization between new function and old structure with the view and technology of the time. For Configurational Interface, the harmonious relation is able to be achieved through “Suitable Dimension”, “Similar Texture” and “Coordinated Shadow”. For example, the related dimensions of new facial bricks with previous bricks, the similar stack-up texture of new stone slabs and previous mortar joints, the continuously horizontal shadows between new metal flat and previous roof tile seams, all exactly demonstrate the dialogue and interaction between new and old materials. ●4.1.3 UNIFORMLY DIFFERENTIAL DESIGN TECHNIQUE If further refine the materials and crafts of the diachronic interface, it will tend to be the discussion about the design techniques such as “Repair old as old”, “Repair old as new” or “Comparison of old and new”, which are mentioned in many researches about the relation of old and new. Accordingly, the design techniques of the relation of old and new in terms of materials and crafts, can be classified into following four types: “the same materials and crafts”, “the same materials with different crafts”, “different materials with the similar crafts” and “different materials with different crafts”, in which the similarity and difference of materials and crafts are regarded as the design elements that are elaborated in the previous part of the thesis. Whereas, if dissect these four design techniques separately, there seems to be only the middle two, “the same materials with different crafts” and “different materials with the similar craft” suitable for a “Correct” diachronic interface, which as a whole can be called “uniformly differential” design technique. It is because that “the same materials and crafts” is only a kind of conservative copy and mechanical return of the previous traditional crafts which is much more applied to old architecture conservation with the view of restoration; and “different materials with different crafts”, though sometimes will appear at constructional interface as a way to optimize the performance, still lack adequate design relation and consideration between old and new that present the continuity of the architecture itself. In contrast, no matter “the same materials with different crafts” or “different materials with the 103

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similar crafts”, both represent a kind of mixture including inheritance and conversion, persistence and innovation. Learning to give up those materials or crafts out of date or backward as well as preferring to develop and recreate those materials and crafts needed to be preserved, is the rightest way to treat old architecture rehabilitations. In a word, the general design principle of the diachronic interface in terms of materials and crafts, is a back-forth transition from the intervention body to intervention relation, then back to intervention body again, which can guide a concrete design through continuous verifications between each other.

█ 4.2 SPECIFIC STEPS According to the general design principle as well as the theoretical part study above, a set of introductory specific design steps is induced as follows for real projects and practices: ●4.2.1 INVESTIGATE EXISTING MATERIALS AND CRAFTS This part is like the preliminary investigation and basic information analyses for an ordinary building design, which can be proceeded through historical documents reading from libraries or on Internet, examinations and surveys on site with photos and drawings. After summing up all the data, the main representative materials and corresponding crafts can be listed and classified: one group of structural materials is focused on the certain construction way and force path while the other group of cladding materials is concerned with the particular detail construction and decoration texture. Afterwards, based on the pros and cons presented by the materials of current state, a general evaluation sheet for each material can be given to determine whether a material should be preserved or repaired, substituted or demolished. ●4.2.2ESTIMATE POSITIONS AND TYPES OF DIACHRONIC INTERFACES Then, under the dual demands of the current problems (structure or construction aspect) and the general design scheme (configuration aspect like new volumes or elements), the probable positions of pivotal diachronic interfaces can be determined. Furthermore, according to the previous materials and crafts of the interfaces as well as the aim and function of them, the types of interfaces can also be decided (structural, constructional or configurational), which will be the precondition and limitation for material selections and craft design. ●4.2.3SELECT INTERVENTIONAL MATERIALS ACCORDING TO FACTORS Besides the concrete factors such as previous materials and crafts or functions involved in the previous two steps about the intervention architecture itself, those factors of the whole context where the architecture lives should also be taken into considerations, e.g. technology of time, regional conditions. Hence, under the collective impacts of these factors, the range of the interventional materials for a particular interface will be largely reduced and form an initiatory selecting range. 104

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After that, according to the general design concept (e.g. the atmosphere to be created) and the subjective preference (e.g. the architect flavor), the interventional materials will be finally selected and fixed. ●4.2.4DESIGN PARTICULAR CRAFTS FOR DIACHRONIC INTERFACES At length, on the concrete design of the diachronic interfaces, the relationship between old and new should be delicately elaborated under the general principle with a kind of peculiar conception that responds to the history as well as reveals the era. Specifically, this kind of relationship and intension can be demonstrated and judged through different kinds of diagrams (e.g. explosive axonometric drawings, detail sections or elevations) and perspectives. Last but not least, when dealing with a real old architecture rehabilitation project, unavoidably several diachronic interfaces will appear at the same time. Each of them can follow the previous design steps separately, in particular for the former two steps which are absolutely the same, but for the latter two, some horizontal comparisons should be introduced and regarded. That is to say, there must be certain relation or similarity between each diachronic interface in the same architecture, which can to some extent avoid the trivialness and chaos of the spatial forms or language since the perfection of an individual doesn’t mean the coordination of the whole.

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CHAPTER 05 DESIGN PROJECT FOR DIACHRONIC INTERFACES REHABILITATION DESIGN OF EX. CERTOSINA OF PALAZZO BOTTA

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This design project is chosen from the RICH* (Reuse and Improvement of Cultural Heritage) International Summer School which I attended as a student in the summer of 2016. It is organized by the University of Pavia which focuses on the reuse and valorization of Cultural Heritage, especially abandoned or underused churches and religious complexes. The main purpose of this school is to develop sustainable design strategies and solutions in order to satisfy the requirements due to new functions, enhancing meanwhile historical and architectural values. During the two-week study, I listened to some lessons about the reuse theory and design projects taught by professors from different countries, exchanged ideas and opinions with lots of tutors and judges and also did a practical case study with other students from various universities, which in fact expanded my personal horizons as well as deepened my knowledge and understanding of my study object and problems. Furthermore, I also have a rare and good opportunity to enter and investigate the entire historical Palazzo Complex under the guidance of a knowledgeable and prominent staff, through which I took lots of photos on site and had a wide and deep understanding of the history and current context of it. Although there were some parts of the complex that we could not enter and have a general view inside, I still visited the most valuable interior parts of it: for the Palazzo building, I paid a visit to all the exhibition rooms of the natural history museum; While about the monastery, the church, the abandoned units and even the accretion buildings were all investigated inside out. In addition, due to the dossier which is prepared by Prof. Besana and other colleagues of University of Pavia, I also achieved some basic engineering drawings and historical documents of this project as well as of the whole city. As a result, the following design process is developed into three different scales, which is started with the urban and site scales about the public space strategies, down to the architecture scale with the reuse and improvement concept of the space, and finally arrived to the material and craft scale on the specific diachronic interface design and expression according to the previous design methods and theoretical analysis. And for each scale, some factors about material and craft are also mentioned and discussed to contribute to the final material selection and craft design of the diachronic interfaces: such as the material and craft in urban context of Pavia Old City (Region factor), the existing built environment in each architecture of Palazzo Complex (Time factor), and the reuse and structure of Ex.Certosina (Function factor).

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█ 5.1 URBAN AND SITE SCALES ●5.1.1 URBAN CONTEXT AND STRATEGIES Pavia, which was called Ticinumin in the ancient time, is located around 35 kilometers south to the city center of Milan where two main rivers in the Northern Italy, Ticino and Po, intercross and fertilize the vast plain. Since its peculiar and strategic location and resources, many generations of different nations during different periods highly regarded Pavia as an important role in resisting foreign as well as manifesting power, which as a result made great contributions to the gradual urban development of Pavia, from a garrison town to a capital, then to an intellectual and artistic centre.

Figure 5-1: Pavia Map SPE51 in 1585 (paviainweb, museicivici.pavia.it)

Although the city expanded three times (see Figure 5-1) in its long history according to the relics of city walls discovered during different periods (Roman, Medieval and Spanish Times), the present range of the old city has not changed a lot in the past five centuries. As we can see from the series of historical maps of Pavia in the documents from the 16th century, the spatial characters of the old city, especially the central part of Roman Times, have almost remained the same (Figure 5-2). Firstly, there is a clear perimeter of the old city which was the Spanish city wall with portals in the past and substituted with the main roads and Ticino River afterwards. Secondly, most of the roads and streets are orthogonal with the same intervals, dividing the fields into similar block dimensions. Thirdly, each block has a definite and straight boundary along the street while enjoys one or more open spaces (courtyards) inside. Fourthly, there is always some mutation beside a significant or special architecture (church or palazzo) forming a city node (plaza). As a whole, the old city of Pavia greatly inherits those urban features from Roman colonies where the grid plan is adorned with some specific gathering spaces at the

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intersections of decumanus and cardo.

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Figure 5-2: Pavia Map in Different Times(from left to right): late 16th century, 1705, 1875(paviainweb, museicivici.pavia.it)

However, in terms of the individual architecture, the situation seems to be much more complicated and diverse due to its rich history, culture, and religions. For example, there are Romanesque Churches, Gothic Towers, Renaissant Cathedral, Baroque Monasteries, Neoclassical Palaces etc. (Figure 5-3); Besides these large parts of stylish buildings which were mainly built by masonry (bricks or sandstones), recently some modern concrete or steel infrastructures or facilities have been erected in certain vacant areas in order to meet the needs of population growth (Figure 5-4), in particular for both universities and inhabitants.

Figure 5-3: Historical Buildings of Different Styles in Pavia (Wikipedia.it) (from left to right): San Michele Maggiore, Tre Torri, Duomo

Figure 5-4: New Facility with modern structure on Piazza della Vittoria, Pavia (Divisare.com)

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In Meaning in Western Architecture written by Christian Norberg-Schulz, the two main street intercross at the city centre are called decumanus (the trajectory of the sun) and cardo (the axis of the world), which link the four main gates at the border of the city. 110

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As a consequence, nowadays in Pavia old city, on one hand more and more public spaces and greenery have been shrunk or even occupied by new volumes or vehicles; on the other hand, those prestigious historical buildings are abandoned without any function like several desert islands. This imbalance leaded by the contradiction between limited urban lands and growing population is gradually changing the spatial structure and even the life quality of the city. Therefore, how to preserve the traditional characters of the old city and at the same time provide citizens with wonderful urban lives is an urgent issue to be concerned. Consequently, some optimized strategies on the urban level are inevitable to be taken into account since they will give some helpful and instructive suggestions to the generation of the rehabilitation project itself which will be firmly rooted in its urban context. As can be seen from Figure 5-5 (the Orange Dot shows the location of the design project), there are five aspects of the urban scale being analyzed: spatial pattern, public system, transportation system, greenery openness and function attraction.

Figure 5-5: Current Urban System Analyses of Pavia old city

After reading both the current state and the historical evolution of Pavia old city, six typical active characters which should be kept and promoted are induced as follows. (1)Open Space Surrounded by Small Volumes (2)Clear Boundary Defined by Straight Roads (3)Grid Plan Divided by Close Pedestrians (4)High Accessibility of Different Transportations (5)Large Green Opened to the Public (6)Mix-Use of Historical Buildings

Figure 5-6: Diagrams for Typical Active Characters of Pavia old city

Then, compared these with the current situation of the project site (the whole complex block), some acute opposite problems of it emerged obviously:

Figure 5-7: Diagrams for Opposite Problems of the Project Site

(1)Open Space Enclosed by a Large Single Volume 111

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(2)Vague Boundary Formed by Random Buildings (3)Huge Volume Cutting of Lots of Pedestrians (4)Low Accessibility of Any Transportation (5)Large Green Belonging to the Private (6)Uncertain Use of Valuable Historical Buildings After that, the optimized strategies can be carried out step by step on the urban scale of the project as follows (Figure 5-8).

Figure 5-8: Diagrams for Strategies to Solve Current Problems of the Project

First of all, regarding the project complex as several small volumes (namely different blocks) instead of a whole which is the state for the time being, some useless buildings may be demolished in order to create a large continuous open space inside as well as several link paths with outside. Next, so as to make each small blocks more definite, some new volumes or coverings are 112

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supposed to be added to reshape the urban boundary. Then, speaking of the traffic systems, on one hand for the pedestrians, it is quite momentous to introduce necessary public nodes and links at different directions across the site; on the other hand for the vehicles, the nearby bus stops and parking lots are both essential for improving the accessibility of the site from a far distance. Afterwards, based on the distribution of the present greenery areas, the various green resources in the project should be connected with the others (like Tourist Boulevard on the north) to sew a city greenery system. In addition, if considering the functions around, the circulation of the project is mainly from three directions:main commercial street and schools on the south side, university college on the east side and public castle (civil museum) on the north side. As a consequence, besides citizens, students and visitors will be the main part of the people who will utilize the site. And incorporated with the historical value of the buildings on the site, Educational and Cultural Centre is the preliminary orientation of it. Finally, the combination of all the strategies on the urban scale is demonstrated as below.

Figure 5-9: Diagram for Combination Strategy of the Project

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●5.1.2 SITE CONCEPTS AND PLANS After discussing about the urban context and strategies, two substantial potentials of the present site have been exploited: vast greenery (Figure 5-10) and abundant historical buildings (Figure 5-11).

Figure 5-10: Analysis of Current Greenery of the Project Site (RICH Summer School Dossier, 2016)

Figure 5-11: Analysis of Current Historical Buildings of the Project Site (RICH Summer School Dossier, 2016)

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Thus, if combine them together with the supposed function of educational and cultural centre that will be utilized by different people (university members, teenager students, ordinary citizens and tourist visitors), a concept of Natural Experience City Complex is gradually raised (Figure 5-12).

Figure 5-12: Diagram of General Orientation of the Project Site

The Orientation is also based on the other two considerations of the site. One is the property owner, as the whole block (Palazzo Botta Complex) has been belonging to Universita degli Studi di Pavia since 1887, so the new function of it still mainly serves for education and culture affairs. The other is about the present valuable functions, though most part of the complex is abandoned and vacant since 2007, the northern part of the main body of the palace is still open to the public as a natural museum with plenty of precious specimens and exhibitions (Figure 5-13).

Figure 5-13: Photos of Natural Museum Interiors (RICH Summer School Dossier, 2016)

Under this general setting, two parallel site concepts and plans have been carried out: (1)Environment Concept --- Green Bracelet Although there are vast green resources on the site, most of them are private or separated by obstacles (like a fence or wall) now, which cannot be appreciated or viewed appropriately. Besides, some prominent buildings also suffered the similar fate. For example, the two mineral towers on the west façade of the Palazzo Botta which were built in the extension and reconstruction during the 19th century are the combination of Romanesque Style form and Neoclassical decoration language. Inside, the semicircular spaces used to be lecture theatre rooms decorated with exquisite 115

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stucco and cabinetry (Figure 5-14). However, today in consequence of the division of the property and functional shift, the intact appearance of the relics has fading away. The same situation also happened to the Aquarium of Liberty Style in the middle of the large garden with two pools in front, which was erected in 1913 for scientific researchers of the university institution to cultivate and study aquatic animals and plants (Figure 5-15).

Figure 5-14: Photos of Mineral Towers of Palazzo Botta (RICH Summer School Dossier, 2016)

Figure 5-15: Photos of Aquarium in the Garden (RICH Summer School Dossier, 2016)

Thus, an idea called “Green Bracelet” about organizing the greenery with the important relics emerges which is just like the process of making a bracelet connecting different jewels together with specific threads or accessions (Figure 5-16). Above all, use a straight path from south to north to connect all the current relics on the site. Next, change the path deviously to respond to the surrounding profiles. Then, add secondary alleys (east-west direction) to link the main path with several nearby public spaces. Afterwards, hatch textures (grass or pavements) to divide different function areas and at last place some street facilities to define certain new spaces.

Figure 5-16: Diagrams of the Generation of the Site Environment

As a result, the masterplan of the project site is realized with abundant supposed public nodes and 116

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activities to take place in the future (Figure 5-17).

Figure 5-17: Masterplan of the Project and Perspectives of Important Nodes

(2)Function Concept --- Open City Complex Despite the general function of the project has been mentioned above, in a view of so many individual buildings involved in the whole project, the specific functions and spaces of each building should also be properly arranged and organized. As we can see from the current function analyses of the project in Figure 5-18, there are mainly three parts consisting of the whole complex: the west part which was the Hospital Mondino is deserted now and with a typical structure layout of many lines of similar small rooms; the east part which used to be the Palazzo Botta as nobility residence is now served as three separated museums; the south part which was the Carthusian monastery (the architecture to be designed in 117

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the next section) is occupied by several different departments of university. Hence, the state of the whole complex looks quite private and isolated, which is much like a huge monumental obstacle for ordinary citizens rather than an active section belonging to the city.

Figure 5-18: Analysis of Current Functions of the Project Site (RICH Summer School Dossier, 2016)

In order to thoroughly solve this problem and activate all the buildings, the original closed university institution should be shifted and transformed into an open city complex though it still 118

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basically satisfies the needs of the university members. The real operation is shown in Figure 5-19 which primarily depends on the present situation: Firstly, remain the most valuable and potential functions like the natural museum and aquarium exhibition as what they were; then, add new public functions like restaurant and experience centre to where has higher accessibility; in the end, set the other more private facilities like dormitory and teaching place in the hospital buildings, the spatial structures of which are more suitable for the new utilizations.

Figure 5-19: Diagrams of the Generation of the Site Functions

After that, distribute all the specific functions to each space and organize all the circulations based on the current spatial structures and building conditions, which form the plans of different floors (Figure 5-20).

Figure 5-20: Plans of the Project Site (left: Ground Floor, right: First Floor)

Although it seems there is not much change at the first glance compared with the former plans, actually the whole area has been completely integrated with a delicate design of the three-dimensional circulation (Figure 5-21). Thus, anyone inside this complex is able to enter whichever building he or she wants at any point to start his or her own natural adventure.

Figure 5-21: Diagram of Function Distribution &Circulation 119

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(3)Transition Concept --- Portico Space However, only the plans of outdoors environment and indoors function on account of the present potentials are not enough, the connection between them becomes the next issue to be considered. In general, there is a typical phenomenon in Italian tradition that the openness of the space is transitive from urban to individual, from public to private (Figure 5-22). When you enter a certain building, the first thing comes into your eyes is not an entirely closed space like a solid room, but a kind of covering or unlimited space you can still feel the public. The same cases can be seen also in a great deal of public buildings in Pavia (e.g. Palaces or Monasteries). Among them, Portico is the prominent representative of this kind of transition space (Figure 5-23).

Figure 5-22: Portion of Nolli Map of Rome, 1748

Figure 5-23: Façade of Palazzo Brambilla

(University of Oregon,http://nolli.uoregon.edu/)

(LucreziaChiofalo. Palazzi di Pavia, 2002)

And in reality, it doesn’t only work as a traffic or spatial connection between outside and inside, there are also other characters of it to be developed (Figure 5-24). As we know, Portico is a kind of linear space with a proportional section which there is at least one row of columns along the longitudinal side. Thus, in this long direction, the openness serves like a wind hall for climate regulation, which is quite common during the summer; in the cross direction, owing to a proper proportion of the scale and repeats of the columns (as well as vaults), a special rhythm will be achieved sometimes also accompanied with beautiful shadow. In addition, when you halt at any point under the Portico and take a look at the open space between columns, it seems to view a scenery painting enframed by architectural elements. 4

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Figure 5-24: Diagram of Portico Space and its Characters

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Figure 5-25: Diagrams of Portico Space of the Project

As a result, in this specific project, according to the former urban strategies and site concepts, six 120

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vital Portico spaces have been inserted referring to the original porticos at present (Figure 5-25). They are covent traffic space (1), library entrance hall (2), museum entrance canopy (3), restaurant scenery terrace (4), cinema suspended box (5) and bus stop pavilion (6). Although, these interventional additions have different functions, scales and even shapes, they all follow the archetypes of different interpreted characters which derive from the traditional portico space (Figure 5-26).

Figure 5-26: Archetypes of Different Interpreted Characters of Portico Space

Regarding these archetypes as the design standards for the new Portico spaces, the results are presented as follows in different aspects and also form the whole perspective of the site:

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Figure 5-27: Designs of Different Portico Spaces of the Project

Figure 5-28:Axonometric Perspective View of the Whole Site

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█ 5.2 ARCHITECUTURE SCALE ●5.2.1 BACKGROUND ANALYSES After completing the management of the whole site on a macroscopic context, the design reaches the certain architecture to be rehabilitated --- Ex.Certosina (The area of the orange dash-line rectangle in Figure 5-20). If take a look of its historical time line through the related documents (Figure 5-29), it appears that the monastery (mainly the church part) is the oldest architecture in the whole project which may date back to the Middle Ages. According to Michele Chieppi, The church was built on the area of the ancient church of S. Agustinus in Porta Marica, of which is known in the writings of the 14th century of Opicino de Canistris (around 1296-1350). Subsequently it became the church of Santa Maria Virgin and All Saints which housed the humiliated28 community to practice an austere life with labor works, like wool weaving. Furthermore, since the Carona canal passed through this area of the city during that time, many artisans and houses were gathered there to spread this kind of religion order and crafts.

Figure 5-29:Historical Time Line of the Monastery

Afterwards, there were three significant interventions on this architecture. The first one was around 1626-1628, after the church was granted to Carthusian29 monks as their town house, called Certosina, which is the Italian name for a house of the cloistered monastic order of Carthusians, the church was reconstructed by Ercole Turati under the commission of Carthusians, the layout of 28

The Humiliated (Umiliati in Italian) traced the origin of their order to the Lombard nobility at the beginning of the 12th century. It was one of many spiritual movements contrasting fortunes and widespread wealth, advocating a return to a more apostle life. 29 Carthusian is founded by St. Bruno in 1044 at Grande Chartreuse which is a religious sect known for its seclusion, asceticism and plainness. 123

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which included a single hall with two side chapels and a typical Renaissance Façade. Then, in 1727-1747, the second intervention which expanded the church into a Monastery almost formed the structure at present. There were two courtyards in sequence surrounded by partial porticos with vaulted ceilings and the façade was also changed into Baroque style which was quite popular during that period. After that, in the next turbulent century, the monastery suffered a lot from the religion to Duke, then to the government and university. Finally, in 1865-1887, the last intervention was carried out under the commission of university to serve the architecture as a scientific institution with laboratories and offices. Therefore, the interior spaces, decorations and roof structures were altered seriously to meet the new function demands while a few inferior accretions were added to the previous buildings. As a consequence, today the situation of the architecture is not so good. First of all, the environment is negative (Figure 5-30), especially the three courtyards belonging to the architecture. Courtyard 1, which was called Corte Civile (Civil Court) in the past and mainly to receive people from main gate, is now useless and deserted only enclosed by solid walls; Courtyard 2, on the other side, named Corte Rustica (Rural Court) before and regarded as activity space for monks living inside, is also vacant only with the ancient uneven pavements; Courtyard 3, which formed subsequently by the parapets and small temporary houses in front of the church, is not only owned by the private for planting in a poor quality, but also blocks the main façade of the church and obscures the view connection between the public street and inside.

Figure 5-30:Environment Analysis of the Monastery at present

Secondly, the space inside the architecture is discontinuous and discrete (Figure 5-31). As is shown in the structural analysis, if dismantle the architecture piece by piece into every single artifact, there seems to be 11 individual structural units which are defined by different roofs. Since some of them were built during different periods and the others were for different functions, the floors and heights of each unit are also varied quite a lot. As a result, different functions are distributed in different areas with their own traffic system. For instance, there is a small steep 124

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stairs inside Cancer Centre to link the upper level with the ground; two portions of Psychology Department are connected with a main staircase behind the church as well as another intimate stairs inside Nervous System Section on the ground floor. If also considering the other traffics for shared use in circulation analysis, the low efficiency and accessibility are comparatively obvious. For example, there is only one staircase at the south end of the three-story slab-type building unit which links the second floor with the first floor. Therefore, if anyone wants to reach the north end of it on the second floor, he or she needs to walk about 25 meters which is far beyond the fire regulations. What is worse, the only way to enter this staircase on the first floor is to go through an outdoor corridor without any other links or functions

(a)

(b)

(c) Figure 5-31:Spatial Analyses of the Monastery at present (a)

Structural Analysis

(b) Functional Analysis

(c) Circulation Analysis

However, from another point of view, there are still some merits discovered in the architecture that may be exploited during the rehabilitation. In terms of the structure, the arch walls with buttress of double height inside the church and the continuous cross arches on column-wall supports along the courtyards greatly inherit the constructional tradition and manifest the splendid classical techniques of the past. Besides, if take a look at the plans of the architecture (Figure 5-32), it will be revealed that the most part of the effective structure is based on the shear-bearing walls at certain intervals (normally 3000-6000mm) and with quite strong thickness (around 600-800mm, depends on the floors or height of the structural unit). Thus, plenty of unimportant walls and floors can be identified and dismantled from the architecture to recreate some larger spaces, e.g. the church hall. In addition, a kind of spatial character can be indistinctly sensed through the plans of three floors: a linear passageway (a portico or corridor) links a row of individual space rooms juxtaposed side 125

CHAPTER 5 DESIGN PROJECT

by side along it. It works as a public transportation space and also provides the transition of different space experience (which has been elaborated in 5.1.2 (3) Transition Concept).

Figure 5-32:Plans of Different floors of the Monastery at present

●5.2.2 REHABILITATION CONCEPTS As a consequence, the rehabilitation concept of the architecture derives mainly from two significant aspects: function reuse and space improvement, which greatly rely on the reading and revelation from the background analyses. (1)Reuse Concept --- Weaving Process Experience 126

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

As is invoked in 5.1.2 (2) and the related plans in Figure 5-20, the monastery will be oriented as the Natural Experience Centre in the whole Natural Experience City Complex Project. However, compared with the traditional and general exhibitions in Palazzo Botta (Natural Museum), the contents and ways of presentation in this historical building should be much more differential and explicit. Hence, based on the history of the architecture and the cultural tradition of the land, weaving is selected as the main theme to activate the interaction between nature and humans (Figure 5-33).

Figure 5-33: Diagrams of the Generation of the Reuse Function of the architecture

It is known that the textile is a traditional and typical manual product made from natural resources like vegetables or animals, which is generally shaped from fibres to yarns, then be loomed into the textile. Thus, the whole process of weaving a textile can be divided into two main steps: making yarns and looming. About the first main step, the concrete processes depend on the original resources. For example, in terms of flax (widely planted in this region), there are totally 7 steps of forming yarns while for silkworm (also famous in the northern Italy ), only 6 (Figure 5-34). And for each steps, a peculiar room or space (indoors or outdoors) as well as some specific devices and instruments should be designed and considered, which helps to motivate the further designs of the spaces afterwards. Speaking of the second main step, the differences are largely based on the loom machines and corresponding tools for weaving. For instance, there are mainly three types of manual looms (Figure 5-35): the ancient warp-weighted loom for weaving large cloths and tapestries which involves two weavers stand on each side walking back and forth, the most common dobby loom for medium textiles weaving with treadles on a chair and also the small back-warp loom that a weaver stands with warps fixed around his or her wrist.

Figure 5-34: Diagrams of the Processes of Yarns from Different Natural Resources

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Figure 5-35: Different Types of Loom Machines Left: a Warp-Weight Loom (Penelope Walton Rogers, Textile Production at 16-22 Coppergate) Middle: a Dobby Loom (The weaver workshop, Engraving XVI century, www.istockphoto.com) Right: a Back-Warp Loom (The Warp and the Weave, http://www.spirasolaris.ca/sbb4g1dv.html)

Therefore, the whole weaving process can be experienced through different types of senses and enable a visitor (or a freshman about weaving) to learn some basic knowledge and practice from those weaving craftsmen and artisans(Figure 5-36).

Figure 5-36: Diagrams of the Interactions between Different Users

(2)Space Concept --- Random Promenade Experience Also according to the general plans of the Natural Experience City Complex in Figure 5-20, there will be two entrances, one at the east side nearby Piazza Botta and the other at the west side close to the main sightseeing street inside the City Complex. Consequently, the architecture will be open to visitors thoroughly from different directions as well as provide the convenient path for the public to cross and discover the inner beauty of the historical building. In addition, the recent layouts of the building which is like an S shape surrounded with two courtyards (Figure 5-32) also tends to provide more choices of the circulations. As a conclusion, a space experience of random promenade rather than a planned and fixed route in a common museum or gallery is raised and put forwards. It also thanks to the special spatial character of the existing passageway that makes this concept become more suitable and various. Workshop 1

Passageway 1

New Vertical Box

Passageway 2

Work Exhibition

Old Pathway 1

Loom Exhibition

Tool Exhibition

New Pathway 1

Figure 5-37: Diagrams of the Promenade Route on first floor of the architecture 128

Workshop 2

New Pathway 2

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

For example, on the first floor, there are two different routes (one is indoors, the other is outdoors) interweaved at two main traffic intersections (one is the main staircase, the other is the new elevator) which will make much more interesting routes and feelings through different choices (Figure 5-37). When the weather is not so good, the visitors can stick on the upper route from workshop 1 to different exhibition spaces then to workshop 2 while they can choose whenever they want to enjoy the beautiful view around the courtyard during the sunny day. And for those who have definite destinations like weaving in the workshops or watching exhibitions, they can straightly take the accessible nearby vertical traffic without spending too much time on those unnecessary distances. A variety of alternatives of routes satisfies anyone's demands and requirements which also present all the users with different feelings and experiences each time they enter the architecture. ●5.2.3 SPATIAL DESIGN Under the rehabilitation concepts above, the real spatial designs are carried out from two directions: the horizontal plans and vertical sections.

Figure 5-38: Ground Floor Plan of Ex. Certosina after Intervention

As is demonstrated in the Ground Floor Plan (Figure 5-38), most accretions (in yellow) are dismantled from the original structure while some useful walls or columns (in red) are established to reorganize the inner or outer spaces. For instance, the draw-back of the partition walls of the restrooms inside the large hall which connects the Palazzo and the monastery, gives a much clearer passageway between the two porticos and courtyards; the new substitutions of previous walls behind the elevator are better for the loading transportation and the utilization of the accessory spaces; The other new walls around the courtyards are reconstructed from the previous ones’ situations according to the history (see Figure 5-29, the design plan in 1727-1747). Additionally, the different processes of making yarns are separately arranged in the rooms surrounding different courtyards which also are designed with different plants as the raw materials to use in the processes: for courtyard 1 (the east one), it is utilized for silk yarn producing with a line of Mulberries on the south side of the main path paved with cobble stones, a throwing playground on the north side for twisting raw filaments together into yarns, and two smaller courtyards covered 129

CHAPTER 5 DESIGN PROJECT

with traditional X shape stone slabs and cobble stones for drying off the yarns (Figure 5-39); for courtyard 2 (the west one), it is mainly planted with flaw for producing the original materials of linen fibres divided by some pavements for connections.

Figure 5-39: Perspective of Courtyard 1 of Ex. Certosina after Intervention

Figure 5-40: Perspective of Courtyard 2 of Ex. Certosina after Intervention

Figure 5-41: First Floor and Second Floor Plans of Ex. Certosina after Intervention

And for the upper floors with less dimension (Figure 5-41), the new structures almost keep the 130

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

same as those of the ground floor (in red) and become much lighter on the second floor so that the bearing wall along the longitudinal direction in the middle (in yellow) changes into several steel columns accompanied with a line of glass fibres in between, which resemble the linear corridor as before but with a much newer sense of filtering space (open offices) with lights and interactions (Figure 5-42).

Figure 5-42: Perspective of Corridor on the Second Floor of Ex. Certosina after Intervention

While through the two main sections below (Figure 5-43), the abundance of the different levels and spaces are shown straightly: in the church, the previous accretion of the dividing slab (in yellow) was demolished thoroughly and only replaced by a narrow lightsome bridge at the same level above the central of the original altar space; the new structural walls (in red) are inserted so as to support the upper existing structures as well as the manifest of space transition for different units; the previous ceiling above the workshop 2 is also dismantled in order to reveal the original wood roof system and increase the clear height of the space; the new steel columns substitute the previous solid wall in the workshop 1 to create a small atrium between two levels……

Figure 5-43: Sections of Ex. Certosina after Intervention Upper: A-A Section

Lower: B-B Section

At length, the space of the architecture seems to be flowing and extending in all directions. Although the functions become more and more private and concentrated from ground to upper, from natural to artificial, the feeling of the space which is organized through the kaleidoscope of linear passageway is always like déjà vu and resonates in a common sense of the past lives and stories on situ. 131

CHAPTER 5 DESIGN PROJECT

█ 5.3 MATERIAL AND CRAFT SCALES ●5.3.1 PRELIMINARY EVALUATION After a scope of the general plans and designs on the urban, site and architecture scales, now we have arrived at the definite concern for materials and crafts. Therefore, under the specific steps of the design method of diachronic interfaces (Chapter 4.2), the previous materials and crafts of the existing architecture have been investigated and evaluated one by one. As can be seen clearly in the following Table 5-1, there are 28 different crafts growing out of 7 typical materials, the numbers of which show the certain locations in Figure 5-32. And from the photos taken on situ and technical drawings after the survey, the values as well as the problems are considered and listed, which also lead to the fair judgements and targeted suggestions on them. Table 5-1: Preliminary Evaluation of the Previous Materials and Crafts of Ex.Certosina

132

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

133

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Therefore, as a whole, the main structure consists of masonry walls and arches and wood roof frame while the primary cladding materials are plaster and tiles on the walls or floors, most of which are in quite good qualities and on account of aesthetics and histories should definitely be preserved and restored. ●5.3.2 DETERMINATION OF DIACHRONIC INTERFACES Then in consideration of the spatial designs (Chapter 5.2.3) and the existing conditions of the architecture, there are three significant diachronic interfaces which are most prominent and exemplary to be further developed and discussed. As is shown in Figure 5-44, the axonometric view of the Ex.Certosina after Intervention, besides the arrangement of the environment (like pavements or greenery), there are three primary differences of the architecture (or main transportation volumes added) compared with the previous view (Figure 5-30). The first one is a Portico Space between the main façade of the church and the cross section after dismantling the accretions of the one-storey unit along the main street inside the complex (also preliminary designed in Figure 5-27 as a transition space on site scale). In order to create continuity and save space, the new roof structure is set both on the previous wall with new columns as well as the new wall at the original inclined situation (see the plan drawing of 1727-1747 in Figure 5-29), which serves as a structural interface. The second one is a Vertical Box adjacent to the north façade of the architecture as a part of the main staircase space exposed to the large lawn in the city park as well as a watch tower to observe the outer surroundings. Thus, the new structure is independent of the old one while the new 134

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

volume directly clings to the old architecture to form a continuous inner space which seems like a constructional interface. The third one is a Suspended Bridge inside the Church Hall as a connection between different exhibition spaces. Furthermore, due to its peculiar position, anyone entering the church from the main façade will figure out the holistic configuration of the hall section as well as the consecrated atmosphere foiled by different elements at the first glance. As a result, the bridge in the middle is inevitable to be a configurational interface to strengthen this kind of spatial feelings.

Figure 5-44: Axonometric View of Ex. Certosina after Intervention Positions and Types of Different Diachronic Interfaces

●5.3.3 MATERIAL SELECTION AND CRAFT DESIGN 5.3.3.1 Structural Interface – Brick Portico Space As can be seen in Figure 5-45, actually the function of this Portico Space involves three aspects: Firstly, it is conceived as the transportation connection between the original L shape portico and the existing terrace of the church around the Rural Courtyard, which gives a loop circulation to the exhibition spaces of different floors. Secondly, as a palimpsest of the previous wall next to the church façade which once defined the urban space and private life of monks, a new wall at the same position is erected embedded with the original portal which is left and preserved as a kind of memory; Thirdly, in order to deal with the climate condition, a double pitch roof aligned with the 135

CHAPTER 5 DESIGN PROJECT

original building is formed on the top of the new wall as well as the original wall at the demolished section, which also acts as an amplified entrance from the west side and a cross ventilation.

Figure 5-45: Generation and Function of the Portico Space

Thus, based on these function and space requirements and analyses, the interventional materials are delicately considered and selected. For the structural materials, because of the relatively large volume (the height is 9m, the span is 4.8m while the length is 12m), member bars with high efficiency are much more suitable and economical, such as steel or timber; Also out of the consideration of lightness, metal or plastic sheets are better for the roof cladding; Talking of the cladding materials of the new wall, some textured materials composed with small tiles (such as stone slates, bricks or metal sheets) are prior so as to provide more abundance to eliminate the baldness and vapidness of the large surface. In addition, in the large context point of view, there is a large quantity of masonry old buildings in Pavia old city which greatly inherit the traditional stone craft and metal work while less wood is used in the structure parts of the rehabilitations owing to the humid weather in Lombardy Region. Besides, since there are also some existing bricks and ceramic roof tiles dismantled from the accretions on site which can be reused as part of the new structure, as a consequence, steel frame, metal roof sheets and brick wall are chosen and applied as the basic materials for this structural diachronic interface. (Figure 5-46)

Figure 5-46: Selection of the Interventional Materials and Basic Crafts for the Diachronic Interface 136

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

Finally, it is the interventional crafts and designs between different materials. According to the existing and interventional materials, two types of interventional crafts have been chosen as reference: for the original masonry wall, steel columns are anchored with steel plate to support the roof and keep stability of the structure; while for the new wall, a composite brick wall with built-in steel frame is applied to keep the same thickness with the original portal as well as transfer the upper load to the ground.

a

b

c

Figure 5-47: Reaction Force Distributions of Different Support Conditions

Therefore, in the further determination of each structural element, a precondition is set: the load distribution of the roof should be different for each side of the vertical elements which also can be reflected on the expression of different materials. As a result, different nodes between the girder of the roof and different sides of the columns are designed (Figure 5-47): regarding one piece of portal frame of the structure (and the loads are simplified into a distributed load), no matter it is a beam with two simple supports (a) or with two clamped supports (b), the vertical reaction forces on both supports are the same which is half of the total load applied to the beam. Only with a simple and clamped support on each side of the beam (c), the vertical reaction forces can be different distributed on each side. Thus, for the new wall side covered with bricks where the compression can be much larger since the steel structure is totally hidden and constrained with the brick claddings that reduce the global buckling of the columns, an ordinary bolted nodes with welded plates is set between the girder and the beam on the top of the columns; While for the original wall side where the compression should be less in order not to damage the corresponding timber beams and masonry wall, a special flexible roller connection made up of two semi-circular plates fixed with a steel rod is designed to support the girder. Table 5-2: Loads Applied to the Girder Load Name

Load Type

γ (kN / m3)

Copper Flat(30mm)

Dead

89

Steel Purlin(QHS90*4.5)

Dead

Rigid Insulation

Dead

Wind

Variable

Qtot,uls = 1.35G + 1.5Q = 16.25 kN / m ,

qk (kN / m2)

g (kN / m)

q (kN /m) 6.15

0.119 0.3

0.7413 0.0345

2

4.6

Qtot,sls = 1.0G + 1.0 Q = 11.53 kN / m

Under these preconditions of the structure, the section of the girder and columns can be then decided according to the related calculations according to Eurocode 3 (Table 5-2). First, for the girder, the maximum bending moment (Med) and shearing force (Ved) of the upper load in ULS (ultimate limit state) should be smaller than the resistance moment (MRd) and force (VRd) provided by the girder and the maximum deflection (δmax) of the beam and variable load deflection (δ2) in 137

CHAPTER 5 DESIGN PROJECT

SLS (serviceability limit state) should also be smaller than the limited state (L/200 & L/250). Wpl ≥

𝑀𝑒𝑑 ∗ 𝛾𝑀0

=

𝑓𝑦

1 ∗𝑄 ∗𝑙 2 ∗1 8 𝑡𝑜𝑡,𝑢𝑙𝑠 235∗103

= 199.15 cm3,  IPE 220 (Wy = 252 cm3),

Under this section: VRd =

𝐴𝑣 ∗𝑓𝑦 √3∗𝛾𝑀0

=

1591∗235∗10−3 √3 5

𝛿𝑚𝑎𝑥 = 𝛿𝑞 − 𝛿𝑀 = 𝛿2 = 𝛿𝑞𝑣 − 𝛿𝑀𝑣 =

384 5 384





= 215.9 KN ≥ Ved =

𝑞∗𝑙 4 𝐸𝐼

𝑞𝑣 ∗𝑙 4 𝐸𝐼

− −

𝑀𝑙 2

16𝐸𝐼

8

∗ 𝑄𝑡𝑜𝑡,𝑢𝑙𝑠 ∗ 𝑙 2 = 48.75 KN, verified,

= 5.48 𝑚𝑚 ≤ 24𝑚𝑚, verified,

16𝐸𝐼 𝑀𝑣 𝑙 2

5

= 2.2 𝑚𝑚 ≤ 19.2𝑚𝑚, verified,

So the girder can choose IPE 220. Then, for the column on the original wall and beam, the compressive axial force (Nc,ed) in local buckling of the section and corresponding Nb,ed in global buckling of the whole element should be smaller than the resistance axial force Nc,Rd and Nb,Rd at the same time. Nc,e = Nb,e = A≥

3 8

Nc,e∗ 𝛾𝑀0

𝑄𝑡𝑜𝑡,𝑢𝑙𝑠 ∗ 𝑙 = 29.25KN, lmax = l = 6m,

= 1.25 cm2 all CHS sections can satisfy;

𝑓𝑦

If assume χ= 0.5, then A≥ λ=

Nb,ed∗𝛾𝑀1

= 2.625 cm2  CHS 60.3*2.3 (A = 4.19 cm2)

𝜒∗𝑓𝑦 𝑙𝑚𝑎𝑥 𝑖∗ 𝜋

𝑓𝑦



𝐸

𝜒𝐴𝑓𝑦

= 3.12  χ = 0.104  Nb,Rd =

𝛾𝑀1

𝑙𝑚𝑎𝑥

Try CHS101.6*2.9 (A= 8.99 cm2), λ =

𝑖∗ 𝜋



𝑓𝑦 𝐸

= 9.75 KN W = 73.6 cm3, not enough,  CHS 273*5 (W =

277 cm3) So the column can choose CHS 273*5. 138

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

Figure 5-48: Detail Section and Elevation of the Portico Brick Space

Furthermore, in order to make the new brick wall more permeable and coordinated with the church main façade adjacent, several crafts are also used during the construction of the wall (Figure 5-48): Firstly, the bottom of the wall is built with travertine stone slate at the same height of the original toe of wall to form a much solid foundation and protection of the whole structure; Next, several lines of corten steel beams are laid on the top of each structural element (such as the original portal or the new glass window) to play a necessary role in consolidating the structure and form a resonate with the stucco architraves of the ancient masonry walls; Then, as a result, within the empty space of the steel lattice beams, some line pipes and lights can be hidden or fixed easily to achieve a cleaner and purer surface of the wall; Last but not least, large parts of the brick wall are also bonded with some regular intervals where there is no related structure behind such as the staircase to enable people at each side of the wall to see the inner steel structure of the wall as well as appreciate the view of the other side, forming an interesting interaction between light and shadow. More importantly, this kind of construction of the space, in some way, reminds people of the feeling of a traditional portico composed with a solid masonry wall and a series of elegant columns which specially belongs to the site and history (Figure 5-49).

Figure 5-49: Comparison of the Portico Brick Space with Original Portico

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5.3.3.2 Constructional Interface – Vertical Glass Box From Figure 5-50, we can also see some functions that are needed of this Vertical Box: Firstly, its main mission is to connect different levels, from the real scene exhibition of fibre making process on the ground floor (0.0m) to the classroom workshop of weaving on the mezzanine floor (+4.5m), to the work exhibition rooms on the first floor (+5.5m), then to the offices on the second floor (+10.8m). It really plays a very significant role in linking all different spaces together to form a convenient vertical transportation and solve the safety evacuation problem. Secondly, because of its peculiar position which faces the special façade with semi-circular profiles of the palazzo and the big lawn in front of it, the space really enjoys a panoramic view of the beautiful and abundant city garden inside the whole complex, which provides viewing decks at different levels to appreciate; Thirdly, as a three-storey atrium space facing north, a kind of funnel draft effect will be formed which naturally transports the fresh air in summer from the south side of the ground to the top as a way for natural ventilation while in winter prevents the cold wind by the insulated facade.

Figure 5-50: Generation and Function of the Vertical Box

Thus, based on these function needs and studies, the interventional materials are quickly determined. Since the new structure is self-supported, the main concern of the interventional materials is focused on the cladding of the Box. Glass is the first one coming into mind due to its transparency and good insulation properties. Then, in order to support this cladding layer, a structure with three-storey height should be introduced and steel is absolutely the best choice due to its simplicity and lightness. The same reason also goes to the roof cladding material for the Portico Space that metal sheet is much lighter and sustainable. And for the stair slabs, since they link the traditional spaces covered with some solid materials such as plaster, more traditional materials should be used to connect and coordinate with them, like reinforced concrete and stone cladding. As a consequence, transparent insulating glass, steel structure, metal roof sheet, reinforced concrete slabs and terrazzo are selected for the construction of this diachronic interface. (Figure 5-51) Then before the next step design of the interventional crafts, three reference crafts are firstly introduced: Glass Roof supported by Steel beams nailed with the existing masonry wall, Glass Curtain Wall supported with Steel studs anchored with the existing masonry wall and Gravel Pavement adjacent to the existing masonry wall. As is shown in Figure 5-52, all the constructions of the diachronic interface are delicately designed in details: for the cladding glass, a 5+5+5 double-layer tempering glass is chosen and the size of it is standardized in the same width (1000mm) and two types of length (2850mm & 2150mm). Also in order to weaken the steel frame effect of the glass, all the glass panels are fixed with pointed supports at angles with back steel rods (dia. 50mm) and glued together with silicone resin; To achieve the same effect of slenderness 140

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

of the vertical structure columns at the angles of the Box, a special section of the steel columns is chosen --- cross section, to dissolve the big size of the column (300*300mm) through the shadows created by the grooves; And so as to solve the water drainage issues, at the ground close to the Box, a surrounding gravel pavement is laid above the water ditch which also defines and highlights the difference between the old and new.

Figure 5-51: Selection of the Interventional Materials and Basic Crafts for the Diachronic Interface

While for the inner space of the diachronic interface, the surface of the existing walls is also elegantly treated: for the detached parts exposed with original brick structure, the surface is simply washed and covered with transparent film to show the positions of the previous walls and floor; for the other parts, new plain plaster is painted while the frames of doors and windows are covered with new corten steel. In the middle narrow gap of the staircase, a piece of vertical curtain made up of hundreds of wood yarns is set as a space separation from each side of the stairs and a display board for the textile works related to the theme of the building. As a whole, the slenderness and accuracy of each material and element contribute to the forming of the peaceful atmosphere of it.

Figure 5-52: Detail Section of the Vertical Glass Box 141

CHAPTER 5 DESIGN PROJECT

5.3.3.3 Configurational Interface – Suspended Metal Bridge As a section view of the church hall in Figure 5-53, we can see much more clearly the relationship of the Suspended Bridge with the corresponding spaces: On one hand, it is a significant horizontal connection between the terrace on the north and the tools exhibition on the south, which is just under the original Baroque floriform glass windows and the centre of the pointed cross arch. On the other hand, due to its prominent position in the hall, it becomes the best viewing deck both for the majestic and solemn space and a large exhibit on the wall from a new point of view. Although these needs of the diachronic interface seem quite simple, the interventional materials of it still should be properly considered due to the important and special role of the church. Firstly, it is without doubt that the structural material of the bridge should be steel which is lightweight and reversible to support. Next, in terms of the cladding material of it, metal and glass sheets Figure 5-53: Functions of the Suspended Bridge are better choices due to their less weight and better durability. Then to think about the cladding materials of the back wall and ground floor, a warm and cozy material like wood is more suitable for the vertical exhibition wall to act as a foil to the atmosphere while a solid and durable material like stone is better for the ground which is always humid in this region. As a consequence, steel structure, metal sheets, glass plates, wood panels and terrazzo are selected for the configuration of this diachronic interface. (Figure 5-54)

Figure 5-54: Selection of the Interventional Materials and Basic Crafts for the Diachronic Interface 142

MATERIAL AND CRAFT STUDY OF DIACHRONIC INTERFACE IN OLD BUILDING REHABILITATION

About the interventional crafts of the suspended bridge, three reference crafts have been chosen: the Orthogonal Steel Truss, Glass Slabs with Steel Frame and Corten Steel Plate Anchored with Steel Studs, and transformed to fit the situation of the bridge. However, since the span of the bridge is quite long (5.4m) and the height of it is relatively short (1.1m), two vertical steel rods in the central part of both sides of the bridge are added, forming a third supports to reduce the bending moments of the bottom girder as well as the reaction forces on the existing masonry walls. At the same time, the smaller steel truss chords inside the metal claddings are manifested through the triangular perforated pattern on the rest parts, which gives a coordinate texture with the exposed double-high brick arch of the hall. For the other parts of the configurational interface shown in Figure 5-55, the back exhibit wall is covered with a large piece of translucent textile and fixed with wicker studs and frames, which has a similar material tone and texture with the huge loom machine in the middle of the church and the curve textile ceilings above both side chapels; The ground of the church is also separated by different types of stone claddings to strengthen the main hall: the middle part under the double high arches is paved with terrazzo divided into small portions by steel strips while the side parts are paved with polished marble slates to recover the sense of an old church in Renaissance. Besides, the left surface walls are just simply painted plain plaster to form a monolithic space. Eventually, from the whole cross section of the church, a perfect and compact configuration is created through the mixed use of different materials and coordination with the original space.

Figure 5-55: Detail Section of the Suspended Metal Bridge 143

CONCLUSION AND PERSPECTIVES

CONCLUSION AND PERSPECTIVES

█ FINAL CONCLUSION “Stat rosa pristina nomine, nomina nuda tenemus.”30 --- Umberto Eco, Il nome della rosa In the old building rehabilitations which are more and more nowadays, the so-called old and new relations are always halted at the pale interpretations and the exaggerated expressions, gradually losing the real concern about construction itself, especially for the exploration of the nature of the relationship about material and craft, which is few and far between. Therefore, this paper attempts to start with a tangible and concrete study object: the diachronic interface, which is composed of different layers of material and craft, to completely enunciate the connotation of the old and new relations as well as provide theoretical guidance and assistance for the practical design and construction of the diachronic interfaces. Among them, the most important point of view is to prepose the relationship of the diachronic interface, namely, focusing on the analysis of the inherent relations between the existing materials and crafts in the old building and the interventional materials and crafts to the old building, from which some creative design strategies that respect the true value of the old building can be inferred. In addition, some related conclusions have been revealed and obtained during the specific study process and listed as follows: (1) The diachronic interface is the definite position of an old building where the materials of different historical periods exist and connect practically with some certain crafts. Its concept includes the diachronic continuity and synchronic connection. (2) Three main causes of the diachronic interface: damage of the structure, lack of the enclosure and alteration of the space. (3) Four main factors for selecting materials of the diachronic interface: times developments, regional differences, functional requirements and architect preferences. (4) According to the material and craft, the diachronic interface can be divided into three categories: the structural interface, the constructional interface and the configurational interface. (5) In terms of materials and crafts, there are three general design principles for the diachronic interface: "appropriate" material utilization, "harmonious" relation expression and "Uniformly Differential" design techniques. (6) In terms of materials and crafts, there are four specific design steps for the diachronic interfaces: the investigation of existing materials and crafts, the estimation positions and types of the diachronic interfaces, the selection of interventional materials according to factors, and design of particular crafts for the diachronic interfaces. At the end, a specific design project is selected: rehabilitation design of Ex.Certosina of Palazzo Botta in Pavia, as an application of the previous theoretical conclusions. In particular, three specific diachronic interfaces belonging to different types are highlighted and elaborated on a material and craft extent, which are based on the abundant analyses and study of the building environment and cultural context.

30

In Latin, the translation in English is “(if) the pure rose remains in name, we have only the naked names ”. 146

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And after the entire study and design process, I have two main inspirations to be shared: First and foremost, I have a further thinking and understanding of the connotation of the diachronic interface mentioned in the introduction chapter. About the term "synchronic connection", it should refer to the objective entity that is composed of both the original materials (and crafts) and the interventional materials (and crafts) at a certain period. Consequently, the study concentration is the objective connection method between different materials based on their properties while the differences between the old and new are weakened. As Marco Frascari said in The Tell-the-Tale Detail, "The art of detailing is really the joining of materials, elements, components, and building parts in a functional and aesthetic manner." Thus this kind of emphasis on the functional utilization and visual aesthetic between materials and the formation of specific crafts can be regarded to be subtle and practical. That is also the basic starting point and clue of the whole structure of this paper. While about "diachronic continuation", it is more like the meaning exploration of the diachronic interface in a deeper spiritual dimension behind the physical "synchronic connection". It is mainly because the "diachrony" defined by Ferdinand de Saussure need to introduce the concept of time evolution. At this point, the diachronic interface is no longer just a static isolated object, but is a dynamic mechanism and meaning carrier gradually changed with the environment, history, culture and society as a whole. Among them, the study key point is the subjective continuation between the old and new materials (and crafts) while the connection for a specific location recedes to the second place. Therefore, this kind of focus on the material and craft expression formed by social ideology must be sublime and abstract. At the beginning, the diachronic interface may be just as the reminiscent and the respect for the past of the old building, gradually wrapped with its own patina of history during years, continuously growing on the old building and becoming part of it; In the next round of the rehabilitation, it will become an old layer of memory of the old building, or be marked, or be remembered. Hence, only through the combination reading of the two connotations of the diachronic interface, the entire appearance and true meaning of the diachronic interface can be described and characterized clearly. Secondly, in the course of the field research of the study cases (actually 55 out of the 115 cases are studied on site in grey background in Appendix 2 Table A2-1), I deeply felt that if want to truly understand and recognize the diachronic interface, the perception on site is very important and inevitable. For example, I once read a rehabilitation case (Can Ribas Factory in Mallorca) on the Internet, which left an extremely deep impression on me from the design concept to the photos of the real site and inspired me to pay a specific visit to it. However, after a tough and long searching experience, finally I arrived at the place. However, completely beyond my expectation, the real situation there is totally different from what was demonstrated on the website: the square is almost stark without any people around, all the transformed factory houses are tightly closed, and even the open "bus station" along the street is still empty. When I was wandering in the sunset scene, the only thing I could feel is that a suppressive and gloomy atmosphere I never felt in the other parts of the city. As a result, I deeply realized that no matter it is out of the academic rigor or respect for research issues, there should be some critical and independent perception and thinking of the real cases through more direct first-hand information collection to deduce even a small conclusion. And only through this way, all the conclusions and results from the study can be much closer to the reality and persuasive.

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CONCLUSION AND PERSPECTIVES

Last but not least, I need to admit that though the research framework, methodology and viewpoint of the whole thesis are universal, there still exist some differences which depend on the time and area when studying a specific case. Therefore, this paper focuses on the study of the situation of the rehabilitation projects in Western Europe after the 1930s in order to be more accurate, detailed and targeted to analyze deeply and systematically. However, this will inevitably lead to the limitations of the study contents and results, especially in dealing with the same problem in China or other regions, a certain conversion should be made before the applications. Secondly, about the elaboration of the study object, more emphasis are laid on the analysis of the "synchronic connection" at a certain period (like from a certain state to a current state), and inevitably reduces more from the "diachronic continuation" perspective to have a macro overall understanding (only in the interventional craft expression section, some case analyses have involved). In addition, limited by the time and energy, the current number of study samples is also limited which can only give a relatively macroscopic qualitative analysis and typical practices, and more clear quantitative conclusions of the study need to be further studied and analyzed afterwards. █ FURTHER PERSPECTIVES Although the writing of this article has been ended here, the knowledge and doubts that have been gained throughout the study have made me realize the lack and the broad potential and value of exploration in this field. For example, in the further exploration of the old building rehabilitation in Western Europe, whether there exist some special diachronic interface, such as the enclosures for portico space, the covering of the courtyard, the placement of the vertical staircase, the connection of the horizontal bridge, that can be systematically analyzed and studied; and also some innovative uses of the regional materials, such as the Italian stone and metal, can be much more discussed in terms of the diachronic interface in details; and for the same problem in other regions, whether it can make a similar research analysis based on this thesis as a reference, such as for the rural wood structure, raw-earth structure, and other types of material and crafts. Therefore, I just hope to use this paper only as a beginning of this study issue, refine and generalize some of specific problems involved in the next possible further academic research and study through a larger number of theoretical study and research combined with the design practices, which can make up for the deficiency here and contribute my trivial efforts to the development of this field.

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ACKNOWLEDGEMENTS

Acknowledgments As the most significant outcome and harvest during my graduate study, this thesis condenses hundreds of days of sweats and efforts in spite of the limited contents and volume. It is just like a process of planting a tree, the gradual growth and eventual abundant fruits can’t be separated from plenty of cares and helps from others. First of all, I would like to express my gratitude to my Chinese supervisor Pro. Zhang Ming, who gave me numerous helps from the selection of the thesis to the establishment of the outline, even to the elaboration of words and sentences based on his wide and rich knowledge as well as experience. Furthermore, he also provided me with very precious opportunity to practice and learn in some real projects which greatly benefited my personal design ability and professional quality. Last but not least, it is him that sincerely supported me to study abroad and expand my horizons which finally lead to the birth of this paper. Then, during the one-year study in the University of Pavia in Italy, I really met quite a few prominent and benevolent professors who also assisted me a lot with the further study of the thesis. Among them, I unfeignedly appreciate my Italian supervisors Pro. Daniela Besana and Pro. Tiziano Cattaneo. For the former, it was her genial and patient instruction and guidance on the design project during the RICH summer school in 2016 that enabled me to have confidence in further developing and improving the thesis and related design under a vast knowledge of the corresponding context. For the latter, his thoughts in class and comments on my thesis expanded my mind in many aspects. In addition, I also wish to thank Pro. Sandro Parrinello and Pro. Carlo Berrizi, to name just a few, who shared with me lots of their personal experiences and advices. Furthermore, my sincere thanks also for Pro. Cheng Yi, Pro. de Lotto and Ing. Cecilia Morelli di Popolo who were the responsible people of the program, my colleagues Lu Yao and Pan Si who helped me to deal with lots of domestic affairs during my stay in Italy, my senior students Zhu Zhenyu and Qiu Hanze who gave some personal tips on writing the papers, and also my friends such as Li Xukun, Qi Hanyu, Deng Junwen, Valentina Zanderigo, Dascia Kryvko, Doc. Veronica who also studied in Pavia with me. Eventually, the highest gratitude to my parents and granny, who taught me how to deal with the life and treat anyone or anything through their own actions.

Shen Yue 19 , June, 2017 th

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