University of California, Berkeley

University of California, Berkeley

This project is dedicated to the memory of a beloved friend and a giant in the field of fire protection engineering, Professor R. Brady Williamson. A. Astaneh-Asl

Fire And Structural Safety A Hot Topic For Engineers, And The Nation ScienceDaily (Jun. 10, 2007) — Earthquakes and explosions grab the headlines when structures are toppled, but often the Achilles’ heel of engineering is fire.

“Many recent disasters involving fire have generated lots of high-level reports suggesting that the United States has a significant lack of expertise in the area of structural fire safety,” Kodur (Prof. Kodur of MSU) said.

SUMMARY Two spans of the Mac Arthur Maze, a steel elevated freeway in Oakland, California collapsed on April 29th, 2007 due to a fire caused by an overturned tanker truck. The day after the collapse, we started this NSFfunded SGER to document the damage and to collect perishable data and material. The collected information consists of photographs and sketches of the damaged and undamaged areas, original drawings and postcollapse drawings and contract documents that were issued for repair and replacement. We have also been able to stop recycling of the firedamaged steel girders and save 21 of the 26 fire-damaged and collapsed steel girders for future investigations by the NSF researchers and others.

I-80

I-580

Collapsed Intersection during Fire (Source of Photo: www.sfgate.com, San Francisco Chronicle Newspaper) Bay Bridge

MacArthur Maze

Berkeley

San Francisco

Oakland

Location of Mac Arthur Maze

Project and Its Objectives • The project was a NSF “Small Grant for Exploratory Research" • The main objective was to conduct a reconnaissance of damage to learn lessons and to document the damage and to collect perishable data for further studies by research community

Research Team: Abolhassan Astaneh-Asl, Ph.D., P.E., Professor and P. I. (UC-Berkeley) Carlos Fernandez-Pello, Ph.D., Professor, (UC-Berkeley) Jin Son, Graduate Student, (UC-Berkeley) Lev Stepanov, Ph.D., Senior Experimental Researcher ,(UC-Berkeley) Mark Thomas, Graduate Student, (UC-Berkeley) William Mac Cracken, Laboratory Development Engineer, (UC-Berkeley) Roxanne Makasdjian, Video Documentation, (UC-Berkeley) Beata Najman, ERSO Staff, (UC-Berkeley) Sarah Yang, Media Relations, (UC-Berkeley) David McCallen, Ph.D., Director of the Engineering Technology Center (LLNL) Charles Noble, Lead Engineer for Critical Structures, (Lawrence Livermore National Lab.) Kambiz Salari, Staff Scientist, (Lawrence Livermore National Laboratory) Casey Heydari, Senior Market Developer and Analyst, (MSC Software) James G. Quintiere , Ph.D., Professor (University of Maryland) Ken Bukowski, Councilmember, (City of Emeryville) Maurice B. Kaufman, Public Works Director, (City of Emeryville)

LLNL Sponsor: National

Science Foundation

The opinions expressed are those of the author and do not necessarily reflect the views of the University of California Berkeley, The National Science Foundation or other agencies and individuals whose names appear in this presentation.

Examples of Past Bridge Fires





Why would anyone do such a thing? — people are out partying, and someone says, 'Let's burn the bridge!' " says Joseph Conwill, editor of the periodical Covered Bridge Topics. "It's a recreational thing." Partly as a result of vandalism, the number of covered bridges in the country has declined more than 40% over the past 50 years, to about 750. Even some of the famed bridges of Madison County, Iowa, have been vandalized. One was destroyed by arson five years ago.

Examples of Recent Bridge Fires Railroad bridges are not spared either…..

April, 2008 Cause was arson?

Examples of Past Bridge Fires Railroad bridges are not spared either…..

Beaver River Railroad Bridge, PA, 2006


Reference: “Fire Protection of Steel Bridges” By Paul P. Greigger, Ph.D. , Team Leader, High Performance Coatings Research, PPG Industries, Inc., Springdale, PA Arthur J. Parker, P.E. , Fire Protection Engineer , Hughes Associates, Inc., Baltimore, MD


The Alabama Bridge (I-65 over I-59) Fire Collapse (Jan. 5, 2002) It all began when a car pulled in front of a gasoline truck to avoid missing an exit, and the truck, to keep from hitting the car, swerved and plowed into a bridge support under I-65 Southbound. The truck, which was hauling 37,475 liters (9,900 gallons) of fuel, exploded into a fireball that was estimated to have reached more than 1,093C (2,000F) at one point. The heat caused several of the bridge's steel girders to sag approximately 2 to 3 meters (7 to 10 feet), collapsing the structure.

Photos: Alabama Dept. of Transportation

National Standards are developed based on research and actual performance of bridges subjected to fire NFPA 502: Standard for Road Tunnels, Bridges, and Other Limited Access Highways, 2008 Edition

National Standards are developed based on research and actual performance of bridges subjected to fire National Fire Protection Association (NFPA) Technical Committee on Road Tunnel and Highway Fire Protection develops and maintains the The NFPA 502, Standard for Road Tunnels, Bridges and Other Limited-Access Highways

NFPA Fire Standards are beginning to move in direction of “Performance –Based Design (PBD)” and away from the current “Prescriptive” methods.

In PBD , one can design the structure for a desired performance from preventing collapse to rapidly returning to full service after a short inspection. To develop such PBD methods, the data from actual behavior of bridges and buildings subjected to fire, specially steel structures, are extremely important.

BACKGROUND ON MACARTHUR MAZE The Distribution Structure (Mac Arthur Maze) was initially built as part of the eastern approaches of the San Francisco-Oakland Bay Bridge. Later, during the 1950’s and 60’s other branches were added to the intersection. The collapsed two spans were part of these additions. Still later, during the1990’s another major branch was added to replace the Cypress double deck freeway, just to the south of this intersection. The Cypress structure collapsed during the 1998 earthquake killing 42 commuters.

MA Maze

Berkeley SFO

OAK

Bay Bridge

Location of MacArthur Maze Location of the Mac Arthur Maze: Mac Arthur Maze, shown in Figure 1, a collection of seven elevated freeways is located almost immediately to the east of the San Francisco Oakland Bay Bridge in California, Figure 2, and primarily serves as a structure to distribute the traffic on the Bay Bridge to the Interstate freeways I-580, I-80 and I880 to the east of the bridge.

The Collapse

In the early hours of Sunday April 29th, 2007, a tanker truck while traveling on I-80 southbound and carrying about 8,500 gallons of gasoline overturned and caught fire. The tanker truck came to rest almost exactly at the location where I-80 passes under the I-580.

The Collapse I-580, a steel girder structure crosses over I-80. The fire occurred in the space between these two freeways resulting in extensive fire damage to I580 and collapse of its steel girders above the fire. In addition, the steel girders of I-80 below the tanker on fire received significant fire damage due to overflow of the fuel and the continued fire on the ground.

I-580

I-80

I-580

I-80

Figure 4. Collapsed Mac Arthur Maze [2]

The Structure of the Collapsed Freeway The structure of the Mac Arthur Maze that collapsed consisted of two simply supported spans, with each span having six steel plate girders supporting the roadway reinforced concrete slab. The steel plate girders were in turn supported on two T-bents, one on each end and a U-bents in the middle. Figures to the right and below show schematic views of the collapsed area before and after collapse. Notice that the box girder on top of the “U-Bent” also collapsed during the fire, however, it is shown on the ‘after Collapse sketch for clarity. This steel box girder was supporting the reaction of the six plate girders on each side of the U-bent.

The Structure of the Collapsed Freeway The T-bents of the collapsed portion originally consisted of a a trapezoidal steel I-shaped plate girder supported on rectangular reinforced concrete piers, which in turn were supported on the concrete foundations. were originally MacArthur Maze consisted of

Reconstruction Plans

PREVIOUS EARTHQUAKE DAMAGE The connector that collapsed due to the fire was built in the 1960’s . In 1989, during the Loma Prieta earthquake, the structure sustained significant damage to its reinforced concrete piers, in particular to top of the piers where the steel girders are connected to R/C piers. The author of this proposal, using a Small Grant for Exploratory Research to investigate Bay Bridge (Astaneh-Asl, 1990), also investigated damage to this structure which is just to the east of the Bay Bridge. Examples of damage to top of the piers of Mac Arthur Maze are shown in the figure to the right and below

Damage to Mac Arthur Maze Due to the M7.1 1989 Loma Prieta Earthquake (Astaneh-Asl, 1990)

Close up of Damage to Tee-Bents during the 1989 Earthquake (Astaneh-Asl, 1990)

The Steel Jackets Added as a Measure of Retrofit

The Fire and Collapse of Spans At 3:42 am on the morning of Sunday, A.M. on April 29th a tanker truck overturned on the elevated freeway connectors and started a fire that resulted in collapse of two spans of the Distribution Structure, also known as the Mac Arthur Maze twenty minutes later at 4:02 A.M. Figure to the right shows aerial view of the Distribution Structure (Mac Arthur Maze) and location of the collapsed spans with a close-up of the collapsed spans. Figure 2 shows two views of the collapsed spans before the collapse while fire was still on (left photo) and after the collapse (photo on the right).

FIRE DAMAGE Connector from southbound I-80 to I-880

Collapsed Girders

Collapsed Intersection during Fire (Source of Photo: www.sfgate.com

Bay Bridge Connector to Interstates 580 and 980

Connector from southbound I-80 to I-880

Connector from southbound I-80 to I-880


Collapsed Girders


Two Photos of Collapsed Intersection during Fire (Source of both Photos: www.sfgate.com, San Francisco Chronicle Newspaper)

Bay Bridge Connector to Interstates 580 and 980 Connector from southbound I-80 to I-880

Photo: www.sfgate.com

Photo by Scott Jones from: www.flickr.com

Collapsed Spans of Distribution Structure (Mac Arthur Maze)

Photos Taken on Monday April 30th (one day after collapse)

A. Astaneh (left) and K. Bukowski (Middle)

FIRE DAMAGE

The figure above shows one of the Tee bents that were damaged during the fire. The figure to the right shows a similar bent outside the fire area. Notice the seismic retrofit restrainers added to the bottom flange of the girders in the photo to the right. No seismic retrofit was done to the part that collapsed during fire.

A Tee Bent of MacArthur Maze Outside the Fire Area

FIRE DAMAGE

The figures above show longitudinal girders carrying I-580. The girders were above the tanker on fire and collapsed after significant fire damage and loss of strength and stiffness. The girders were composite with the deck reinforced concrete slab. The shear connectors between the girders and the slab were steel plates fillet welded to the top flange in almost 60 degrees slope.

FIRE DAMAGE

Fire-Damaged and Collapsed Longitudinal Girders of I-580 The photos above show longitudinal steel plate girders of the I-580. The girders were immediately above the tanker truck on fire. The girder seen at the top left corner of the photo to the left is the steel box girder which was also above the tanker truck on fire. And was supporting six longitudinal plate girders on each side. Notice the sloped plates on top of the top flange of the plate girders. These sloped plates were welded to top flange and embedded in the deck concrete slab to provide composite action.

FIRE DAMAGE

The photo above left shows a reinforced concrete T-bents of the I-80 which was damaged during the fire. The photo above right shows similar tee bent at the other end of the span not affected by the fire.

POST-FIRE INVESTIGATION

In the aftermath of the fire the California Department of Transportation contracted Wiss Janney Elstner of San Francisco to conduct tests of fire-damaged material. The photos above show the views of two of the cores taken from the steel-jacketed concrete piers exposed to intense heat during the fire. The cracks inside the piers are visible.

Photos on May 3rd (4 days after collapse)

Photos by Abolhassan Astaneh-Asl

COLLECTION OF FIRE-DAMAGED STEEL

Photos above show the fire damaged longitudinal girders from the MacArthur Maze. In the aftermath of the fire the fire-damaged steel from the Mac Arthur Maze was sent by California Department of Transportation (Caltrans) to recycling plant in Oakland to be recycled. We were able to bring to the attention of Caltrans that such fire damaged steel can be very valuable to the research community in the fire protection engineering. Twenty one out of a total of 26 pieces of girders that were in recycling plant were rescued and currently is preserved in a Caltrans yard near the Bay Bridge for future use of researchers.

Berkeley SFO

OAK

Collapse of Two Spans due to Fire, April 29, 2007

Collapse of Two Spans due to Fire, April 29, 2007






COLLECTION OF FIRE-DAMAGED STEEL

Photo by Abolhassan Astaneh-Asl

Photos here show a longitudinal girder with its shear connecters (left), a typical “fixed” connection of longitudinal girders to the supporting box girder (center) and the steel box girder which was supporting the longitudinal girders. All girders were cut in half and delivered to recycling plant for disposal. Through our efforts and cooperation of Caltrans and recycling plants, they were recovered and now are preserved for the use of researchers in the future.

Seismic Retrofit of Damaged Structure (Currently ongoing)

Seismic Retrofit of Damaged Structure (Currently ongoing)

COLLBORATIVE RESEARCH WITH LLNL

Current Analysis-II

Software: Patran/Marc (Commercial)

Current Analysis-I

Software: NIKE-3D (Restricted to U.S. National Laboratories

Current Analysis-I

COLLBORATIVE RESEARCH WITH LLNL

Photos here show a longitudinal girder with its shear connecters (left), a typical “fixed” connection of longitudinal girders to the supporting box girder (center) and the steel box girder which was supporting the longitudinal girders. All girders were cut in half and delivered to recycling plant for disposal. Through our efforts and cooperation of Caltrans and recycling plants, they were recovered and now are preserved for the use of researchers in the future.

Current Analysis-I

Current Analysis-I

Current status of Perishable Data collection 1. Have collected information and data on the exiting structure as it was prior to collapse. The data includes past performance of the structure, initial drawings and photographs taken prior to the fire. 2. Have collected information on the past performance of the structure including its performance during the 1989 Loma Prieta Earthquake and the damage that it sustained. 3. Have collected some information on the ongoing seismic retrofit of the structure by California Department of Transportation (Caltrans). 4. Have collected information, drawings and contract documents on the repair and reconstruction of the damaged and collapsed portions. 5. Have been able, through cooperation of Caltrans, to stop recycling of the fire-damaged and collapsed steel girders, which had been sent to recycling plant. The steel now is preserved for future scientific use of NSF researchers and others. 6. With the collaboration of scientists and engineers from the Lawrence Livermore National Laboratory, we are conducting a fire analysis of the collapsed structure. The works is in progress. 7. Have provided factual information to public, news media and policy makers.

ROGRESS OF RESEARCH We have done the following during the past 12 months of activities: 1.

Have conducted an immediate reconnaissance of the collapsed freeway starting the day after the collapse and continuing for four weeks. We started the reconnaissance while very little debris from the roadway slab was crushed while all steel girders and other components were in “ascollapsed’ condition and not disturbed by the demolition and debrisremoval crews.

2.

Have obtained a complete color DVD of the fire taken by the security video camera located at the EBMUD site near the bridge. This DVD is arguably the most important piece of scientific and engineering data in existence on actual fire on a bridge leading to collapse.

3.

Have performed photographic documentation of the damaged and collapsed structural components and connections as well as undamaged , but similar components, for comparison.

4. Have collected information and data on the exiting structure prior to collapse. The data includes past performance of the structure, initial drawings used to construct the collapsed freeway and photographs taken prior to the fire. 5. Have collected information on the past performance of the structure including is performance during the 1989 Loma Prieta Earthquake and the damage that it sustained. 6. Have collected some information on the ongoing seismic retrofit of the structure by California Department of Transportation (Caltrans). 7. Have collected information, drawings and contract documents on the repair and reconstruction of the damaged and collapsed portions. 8. Have been able to stop recycling of the fire-damaged and collapsed steel girders, which had been sent to recycling plant and preserve the rescued steel for future scientific use of NSF researchers and others.

9. With collaboration of scientists and engineers from the Lawrence Livermore National Laboratory, we are conducting a fire analysis of the collapsed structure. The works is in progress and some initial results are summarized later in this paper. 10. Have provided factual information to public, news media and policy makers during the last seven months on the causes of collapse and the lessons learned from this collapse.