RESISTING CONFINED BY PERFORMANCE SQUARE ... - J-Stage

Architectural Arohiteotural

Institute エnstitute of of Japan Japan 　

　

ーII】

【カ テ

．

構 造 系 論文 集　 第547号 ， 129−136 ， 2001 年 9 月 J． Strucし Constr． Eng ． ， AIJ， No ． 54ア， 129−136， Sep． ，2001

ゴ リ

日 本 建 築 学会

　

　

　

　

　R ／ RESISTING PERFORMANCE C 　COLUMNS 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 CONFINED BY SQUARE 　STEELOF TUBES

EARTHQUAKE

−

　

Part　3 （

Effectsof

shear

　

　

正 方形 鋼 管横 補 強鉄 筋 その 3 （

柱の せん 断ス

　　　 　　　　　　　　　　　　　　　　　and

ト柱 の 耐 震 性 能

ン

比 が 耐 震性 能に 及 ぼ す影響 〉

＊

） レ生

＊

＊ ＊ ＊

P

＊

崎 野 健 治

，

）

of 　column

ン

；

，

平

クリ

　

コ

パ

移ノ 　

＊

玉

ratio

　

i SAI （11＞0 　Ke η taro　YASUI 　Amin 　AKLA1 丶 厂

Yuping　SUI＞ 　偸 孫

span

　

＊ ＊

安田 健 太 郎

，

＊

ア クラ

，

ア ミン

ン

　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 ■ arld cNperime 【 ltal sh dy of car hquakc −． esisting As the third of all inlegrated theoretical pcrtkrma 【 of sqLLaro tubcd colloroto 　　　　　　 part ． ． ・ colum1 s， this pape ・ deals　 with ef1 ヒct ofshear span ratio （ a、 D ）ol 　 columns on tlle seismt behavioras ， ell as mlhlillg e 且ヒ i elless ofsquare ． ． ， stecl tubes 、 Fou tee reinf r ed concrete ohmllls haviug two kiuds oilshear span 1 ati s f L （ j and 】 ． 5 ere o 1 正 i1 ed b square steel tubes 　 ） ’ ・ ・ ’ ． with fivekind o 止wa 且1 thickliess ． wo e te ted mdei reve sed 且force ・ hiEesuhieotod to enstallrt axial load． 　 The e coiumns ｝cHc Iatera 　 11 is sllown that as colifmcd in s 1uaro stcel tubcs havi1g salllc wall thickncss ． thc Lolumn tilatilasshcar span 1』 ati Qf l ． 5　 bchavcd in a rlluoll ． ． moro dudilelll111nel1電han theshori otulllllwllos sheanl span ratio isl． 0． under axial loadwith n ． O． 33 and 　 T m ke the sllor吐 1unllis ．28 wcro ・ ・ n磊 0． 67ductilc enough ， usc ofthick stee ］tubes with B 43 and B t一 nccdcd 』 ExpcI imelltal 1 esults a ］ so ind にate ha 、rcspodivcly ・ 　 』 　 a’ argel thail 1 ． 5 when the ultima ｛e drift ratio ofthe short colullm with a の ； 1． O was about O ． Olrad g． nla ］ 1erthan that oft11 col IM havillg D ］ ・ 　 the 飢eehube with sallL wall tlli kness ar d 　 the　 con rete having same eompressive sti ength us d 、 　

　

　

】

　

　

　

　

　

　

］】

／

　

（ ）

　

］

じ

　

　

　

　

　

　

　

　

己

且

　

〕

　

　

じ

ノト

　

　

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じ

　

　

　

乙し

lcc

じ

【

　

　

　

　

（， 　

　

己

　

、were

　

山

〜

厂

〜

η

厂

　

’

／

／

”

　

　

（，　

　

　

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芝

　

。

’ ’ ． ．． ．eaJ ’ thqitake −1’ L． ． 1、 stJng pei： mance ， ． sql tll1L S’ tL． ui tubu CO ηfinUtnent ， V， idtii−to−t・ Clii thic． kne． Y、 y JlatJ for’ 」 」 ’ ’ ． shea ． Ctt o 1 ttilncTte dt att Ct ． x icti IOCtd ati ， ， pa tf ． せ ん 断 耐 震 性 能 、正 方形 鋼 管 横 拘 束 、鋼 管 幅 厚 比 、 比 ．限 界 部 材 角 、軸 力 比

Ke ＿ レMJortts

　

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》

　

　

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1

　

　

　

置

　

　

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〜

　

　

　

　

¢

　

　

　

　

　

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’

　

　

じ

　

　

　

　

　

　

　

じ

〔

　

　

　

〜

　

　

　

　

　

　

　

　

　

　

］

　

　

監

、

　

　

「 、 teel tube ， f．

f！

θ

　

｛）

の

ス

バ

ン

1． 　 INTRODUCTION

． ］tし isolle ot ’ −resis1allt tlptl ity馬 the eil ヒ 1iven ethods ． lbr ip911ading arthguake freill1rcedcoll rete colunmis ． ． へs ’ ． ． ． Tlvelltitilaltransvcr se ｝ 10 p or spirals、 tllc steel tubc 、 whcn usod as ansv 1 sc nllnc 、 has siglli 丘i ul advi ilUage fpl． evelltitlg st alting ． ］ concrete tl］ ］ of ’ t 1umll s otion ． and 　 hcllcc load−oa1 》． ingcapacil ）’ of thc　 GQIunul illaddition 　巳au illg ，whicll gene ’ Y reduees 　e 什botive 　ar a 　 　 ’ ． ・ 　 ing failure ． advantage ofl the steet tubc istllat itGall work as tbrm lb星 columll 【 ［ ials for［bmlwQ ・ k、 　 Amther 　 Bocause oi thes

　　 　　　　Coilfinement 111pa1・ ed witll c

c 〔〕 of

　

he 　 shel

且

bolld−sph

　

〔 〕 fc〔 ncrete 》

匸 〕

）

Lbe

　

　

抗

　b ト　stee

　 　

Ω 〜

［

　

　

　

　

　

　

　

　

　

　

　

　

じ

　

　

己

　L

　

　

　

コ

　

）

　

　

し

¢

　

　

¢

　

　

！甅

じ

じ〔）

じ

　

　

　

　

！

丁

　

　

　

　a

じ

と巳

　

ld

　 sl

ヒ）

）

吐

じと

　 111a

　

【 〕

　

vc

　

じ

］

　

且e1

　

｝

【） じ

漲

　

置

olunuls ． and 2 ）e仕ヒct ofshcar spall ratio on thc conflne nent efibcti ． eness f t teet tubos ． hieve these 　 Tt aL ’ ・ 』 b． ．fbulleon square 　〔 ll 1 ete 　 colullms having shear span ratios of L5 　 and 　 l． 〔 ｝wcre 　 ftibri a1ed and tested under 1 eversed cvdi iectives latcral llore 　250111111 　 　 　 ’ ． wlliie subjcctcd to o nstttllt uxial colTlp ． essien ． t ratio 1・ angillg 丘・ Dm 28through 　 The test c lumns were Gonfilled illscluare steel tube with fivckinds of B ． − 33 ， ’ 』 ． ll7 ． vari hlein thc lests was axial ］oud 1． atio n illl vatues oi 0 ． 0． 50 、 and O． 67 ． 　 Thc othc oxpo1 inlcntal

1ubed

I）

　

　

　

　

　

　

じ ，

　

〔〕

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じ

　

　

　

　

　

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と 匸

　

じ

　

　

　

　

　

　

　

　

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、、

　

　

　

　

　

　

　

　

　

　

　

　

　

　

　

　

　

＄

丶

　

じ

　

｛）

　

　

　

　

　

　　

　

　

　

　

牢

　

　

　

　

　

　

　

エ

　

　

　

　

　

　

　

　

　

　

　

　

　

　

　

　

じ

　

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九州 大 学 大 学 院 人 間環 境

学研 究 院

助

　

九州 大学大学院 人 間環 境 学研 究 院 新 口鉄   　 工 修

・ 工 博 ・工 博

教授

　

　

　

）

　

　

喞Assoc ．Prof． ，Graduate School of Human Environment Studies，Kyushu Univ ． ， ． Eng ， 　 ＊ 墜Dr Prof． Hurr Graduate School of an Environment Studies Kyushu Univ ． Dr ． Eng ． ， ， ， ii察Nippon Stee1， Ltd ． ，Former GraduateStudentof Kyushu Univ ． ， M ． Eng ． 零 零 寧 Mitsui Busan ，Ltd 、 Dr ． Eng ． ， 　

　

］

　

教授

元九 州 大 学 大 学 院 　 大 学 院 生 三 井 物産　工 博

129

一

NNII-Electronic 工 工 Eleotronio Library 　Service 　Library

Architectural Institute ArchitecturalInstitute

of Japan

ofJapan

fable1Properties

and

the 2D-$eries columns

results ef

main

pt(easuredrcsults

Detailsot'specimen 11{--N,No)(4) t(11Ml)(s) B/t }L'(kN)(3) .fe(MPa)C2)

Notation

Predictedresults

l""pftxVsuxJstL XJrvt:(kN)(]o)V,m,(ll} X"'rlt/Lx' X"cv(kN){1?)v,,(1.3) X･tm-x Xiu//CkN)(l4)X"uUs)XiTT-(16)X,'ut/(17) XJinaN(kN)(7} R,nay(rad)(8) Ru(rad)(9}

(6)

{1)

O.O17O.022O.025O.03Ge.oso 39039S398413436 e.931.03o.gge.96O,P4 3C)43163343603g2 12012gL]71.]Ol.U7 326327323.321311 L]2l.24L2I1.]31,32 o.7go.goO.84O.87o.gg O.93O.971.03L121.23 30.330.429.829.327.S 6326346]]611579 e.334O.334e.333O.334O.333 2.173.114.296.099.46 1178260432g 354406390396410 O.OIOO.O15O.O15O.O15O,035 T2.33.7DT3-33-2DT4-33-2DT6-33-2DT9-33t2D

T2-50-2DT4-SO.2D35.6 IY2 36.7

e.500

114)'

t17

2.17 4.29

O.499

'1'3-67t2DT6T67.2I)T9-67-2D 37.7 1550 O,667 3.M

389

O.OIO

O.O13

463

e.g4

358

1.09 1.0)'3453)'11]3

60

41g

e,O15

e.O19

SOO

O.g4

.397

82

447

O.alO

e.Oll

476

O.94

410

1.09

l19

296]X92911,51

O.77

L04

O.79

1.l3

O.S6

].39

35.6

14g4

O.667

6.09

43

472

O,Ol5

O.O17

563

O,g4

448

1.0)'

1.63

CL8e

1.55

36.0

1499

O,666

9.46

2g

546

O.020

O.02j

676

e,81

4gO

1.14

1.g8

e.71

1.6)'

N/ axjai loadapplied ,c',co]npressive str ngth efconcrete cytinder Bit/XJ/nHs'/ ",idthtowallthicknessratiool'stceltube at Vniax lateral forcc R,,./ drifi ratio ot'colunlli nieasuredinaximurn 1oad droppedto 95% ot'the Vmax Ru/XJtnu/ drillratio ofcolurrm at which the latera] later'aJ leadceiTesponding to the ultimate tnoment calculated by authors' nlethod [4] v.,/ shear strength calcu]atcd by the modified Ohiio-Arakawa fonnula [3] culculated by the ACI cgde [5] Xiv,,/iateral 1oadcon'esponding lo the u]timate moment ¢

ultimatc

2. EXPERIMENT 2.1

OF TUBED

WITH SHEAR SPAN RATIO OF 1.0

COLUMN$

TESTSPECIMENS In the tubcd

celuinns

"'ith

llcNnraldet'omnationis prcdorninant conlinenient

eft'ect

the

and

through

niainl}･

proportion.the

ordinar}･

Loadingdirection

tubc

provides the lateral

stLLI

conslraining

pt

We-e-

,e,:7g:S,IOIi,,Sli,1,`ll,1`T'i:g,iLekgl//#,O:X:`15.,llii.LO,1";';i,,L)Zl:,1::

s ductitit}, to the

tnough

has bccn the

case

in authors'

veritied

ef

short

tube

stee]

"･idened

shear

anlicipate

that

s'ar>･

the

and

1iusto

also

confinenient

efi'ectivetiess

Nvith shear span ratio ot'tht

under

rcversed

thc tubed

lhe

stecl

i'atio

on

columns

as

having inner",idth

the

of25C)tnm

hars in each longitudinal

to give a perinieler neNt

It ean

section.

This was

well

the

as

be

loadas

seen

li'ornFig. 1 that

and

L'isthe

magriitudc

dixpcrimenta] compressiye

ot'the

cornpressive

The B,,iratio

results.

variables slrcngth

of

Tnay

the

seismic cfibctiveness

The

istwice

eolumn

the

thickiiess,

ofwa]1

of

steel

size

ofthe

2.17mm

tubes, tcn

have

test colutnns

dcpth of

through

shear

"'ere made and tested 250x2SOx50enun prisniutic span rati.o oi' 1,() and are referred te as 2D-series specirnens co]u]nns

concrete

Thcse

section.

9,46nini. In the

sarne

s.pecnnens

inanner

were

the test

as

by

confined

columns

reported

.gquare stee] itiReE 2,

tlie steel tube

clearances

proi,L'dcs

of enly

1Ointn "'ere prox,idedbet",ccnthe loading stub and the steet tubt ut bot]iends ofthe cotunui. 'csislance ral]ier lhan a direct to the axiat stress induced by the a continillg efi'ect to thc cDncrete,

bendingnionient,

Experimentalvariables Bit.,and 2) the

tm)i

tl,.=318)LdPa) uniformls, distributed around the column. co]isisted of t-･elve]2,7mm diameter dcfbrmed bars (D]3, ot' the 2D-series cotunms along with ofthe 3D-serics colunins descrihcd in the Fig.1 she"'s tei"tbrcetnent dctails

of2.449'i.

"'ell as

Aljdimensions in

to

confinement

fivekinds

and

colunin

cnch

ratio

donetbr ensuringthat

axial

applied

steel

e pt

･pm1

constant axial cotnprcssion.

hercaftersimply because the clear hcigh1 of tubes

wholt.

tubes

l

Fig.1 Reinibrcementdetaltsand]oadingc,)nditionot'thespecimens

shear span

latera] load and

cyc]ic

a

it ls reasonable

ot'

e

E

colunui.

Te investjgateefi'ectoC perf'ormanceot'

failas

to

-

-

dei'ornialien

shear

is apt

column

-

eee-N

in

dilatatio"due to i'estrictthe tateral Censequently,

cracks.

[2]-Hnwever･

prcvious "'ork becuuse thc

colunins.

becoinespredoniinant thc

consideration Tltistheoretical

column.

=n

strength

the

uscd

as

well

as

of

concrete

steel

ranges

l) the

were/

interms or Tahle

cylinder.

tubes varied

theirvai)'ing

xva.s

specimens

Ioad,reprcsented

axial

of

concrete

the 2D-series

an]ong

]

axial

thickriess of steeT tube. expressed

"･all

loadratio

]istsoutlines

ofthe

from 2g through 1l7, whilt werc

the same

as

adopted

n{ -N/A,fi ).where

,V

isthe

?D-sericsspecin!ens tlie

for the

axial

tubed

load ratios e{]lumns

interms

applied along

had

isthc

concrete

core

ratio area

and predictedinain 'Ihcse O.33. 0.50 and e.67, two

thcir measured

with

having shear

thickiiess

widlh-to-wall

load.A.

axiat

values

of

of

span

rtLtie

of

2.0

'Thetargeted

l21.

3eMPa.

130 NII-Electronic NII-Electronic

Library Service

Architectural Institute ArchitecturalInstitute

The

ready-mixed

concrete,

with

3D-series speeimens.

well as the

ofthe properties

2.2

of Japan Japan

of

sleels

slump

a

in thisexperiment

used

180mm

ofabout

the same

are

and

maximum

.strength ot' concrete

Compressive

c}'linder

size column

13nim.

ol'

were

to

used

t'iibricate the 2D-seriesspecimens

isgiven in Table 1. Tht

lhe testingnge

a:

as

mechanical

inauthors' previouswork [2]and hence can b¢ tbundthere.

thoseused

as

aggregatc each t'or

LOADINGCONDITIONANDINSTRUMENww10N The loadingapparatus describedin Ref. 7 by

means

the

column

applied

deform reversals

ot' an

in a double

was uscd to

machine

curvature

dcsignedloading historyto the

apply

5MN

with

the

capacity.

'Ihedesigtlcdloading

shape.

loading proge'amcomprised

thc

and

testing

universal

tbllowing ;oadingsteps/

the

reversed

For eaeh

columns.

lateral[oadwns

specimen.

the

atler

foad being

axial

through one 500kN ]rydraulicjacklo displacemcnt-ccmtrolled type alteinating drifi

cyclic

applied

patterntbr the lateralload was 1) the peak drifiratios. detlnedas

with

ratie

height h(=5eOnini)ot'the co]umn, were increasedstepwisc from O.O05 rad to e.02 rad with increment ofO.OOS rad after and 2) beyond R=-{}.C)2 1evcl, rud the pcak ciritl ratios were increasedup to O,e5 rad or until t'ai]ure with iner ment ratio

laleraT dlsplaccmcnt,,Sto the clear

ofthe

¢

thrce

coinplete

ofO.OOS

rad

c},ctes

tuler

one

al

drifi

each

cvclc

at caeh

driftratie level, Detlectionswere each specimen

tongitudinal bars as

the

by disp]acetnent transducefs

nieasured

well

lntoa computer-controlled

thc

as

In addition to the lateral detltclionTMeasurcintnts. the ai'erage axia] dcl'ennatien ot' (D.'l'.}. instrumentation tbrthe detlectionswas iclentical to that used +n the tests describcd in Rct/2. Strainsin steel tube were measured with strain gauges, readingsc t'roni both the strain gauges ?md the D.'I7s",trc t'ed

The

also measured.

was

measuring

confining

.X]1

dataacquisition

intofloppy diskforlateranatysis,

sy,stetn, and stored

2.3 OBSERVEDBEHAVIORANDTESTRESULTS Fig. 2

shevL's

obseived

thc tcsts.

Values

drillratios

experienced

the

As

and

reinoving

For

the

colurn]is

dominant

werc

to

sub.ieeted

regnrdless

the

of

the

afier

nlaxinium

t'roniFig.2.

seen

patternsoi' short toad ol' n=-O.33. shear

crack

axial

thickiiess

wall

The tube

stee]

drifiratio given +n Fig, 2 represent by each specimen. As can be

ot'

loud[evefgreatly inllueneed the

axial

colurnns. cracks

2D-series specimens.

ofthe patte;'ns by cutting

crack

patternswere

crack

of

tubes.

stcel

the axial loadratio became higherthan O.5O,however, the damages

inshort

columns

shear cracks.

primarilycaused by spHtting cracks rather thfln 'I'hc damaged rcgion extended aleng the column height were

1'erall

the

use

the thicker

of

2D-series specimens

regardless

.gtLtl tuhe

could

the

of

T3-33-2D

T4-33-2D

T6-33.2D

R=O.035rad

R=O,04rad

R-O.05rad

R-O.06rad

T9-33-2D R=O.06rad

load levet.but

axial

prevent

effectlvely

T2-33-2D

widening

oflhe

crack.g.andinitigatcdamagesintheshoitcolum;is.

'1'he experimentaT

relationships

the

and

2D-series

specitncns

hystereticloops as the

",hen

well

contining

accninulation

of

aNial are

-

drift ratio

defotination6 - dr'ift ratio

R

curves

plottedin Fig. 3, as the S - R curves tube

steel

the

hystereticlatera]toad V

axjal

contacted

Broketi

the

stages

loading stub.g dueto

'l'he experimental

shortenings.

-R

V

the testing

express

with

t'orthe

in the

curves

R

T2-50-2D T4-50-2D T3-67-2D T6-67-2D T9-67-2D R-O,O15rad R-e.03rad R-U,C12rad R-O,02rad R=O.U4rad

maximum

well as the coiTesponding dritlratio R.,,ai'e given in Table 1 aiong with the ultimate drift ratio R., at whicli the lateral load dropped lo 959･iol' the lv',,,..,Thc nieasured V... given in Tab]e 1

lateralload V... as

:'epresentstheai,erage of

thcmaximum

In addition. three kinds squares

and r4],

V,,,isbased on

the

the

proposed

the

specirntn

methed

them

to

sub.iected

axial

T3-33-2D (B,'t-l17).

not

onl},

under

Combining

observations

the

above

axial

steel tubewith

specimens

Bit < 43

to the

and

by

etl'ect

the stee] tube.

because itsvalue

only

¢

catculated

describedin Rtt/ 4. authovs'

,Xs

specim

ti.

'l'he solid

lines vvith

the brokenlines express the u]tiniate

tlextiral strength

ultittlate

[5].

contlnement

tiltthe at

both ofthem

load with with

the

n=O.33 craek

confined

could enhance

by

steel

end

of

tests. and

the

aKinl

large deformation. For the exiiibited

usingthe

cu[cu]alion

but a]so

method

proposcd by

efi'cctbs'thc

the

stifi'

side

sguares

soljd strength

isdit}i]reilt tl'otn the

inethod

extra coniinetnent

isbeyond

shcnr

and

open

obtained

by

firsttwo

authors

.-LCI melhed

the

+n that

loading stubs.

For

600kN.

ver}･

stublc

.

cyclic

shortenings

ti'ere

i,er}' stnall.

'1'6-33-2D

'I'his nieans thatthc 'l'9-33-2D and

(B,'t=43)

specimens

ti]]tht

responses

end

ol'tcsts.

tubes

largei' than

",ith

Btt /. 43

bothductility and uitimate

the short tubed

O.50, ",as

abrupt

and

colunins exhibited

acconipanied

strength. although the

sliorl

celurnii

"'ith

behavier ei'

utctimutatien

couldn't

degt'adat+on

th y didn't )vloreoi'er. the longitudinal bars in all ofthe

reached

n

strength

lhough (B/1-2S),

the yield strcss both in tension and in coniprcssiori betbre anab'or it patterns. can be said that thc t'nilure patteniforthe shoit ILibcd cotunins under

faiiureaftev tlexureyielding. {)n the other ]]and,under high axial load with

degradationin the

Vun,respeetiveiy,

each

t}'oni web

viewed

Ioadwjth n=O 33. thc short colunin exiiibited more ducti]ebehtiviorus the sleet tube became thicker. The specimens and T4-33-2D (Bit-60) sho;ved largestrcngt1i dcge'atiation fi'o]n R=e.e2rad. {}.025. and O.U35rad,respcctively. (B,'t=82}. but

tleNtiral strength.

2D-series specimens

Xi - R loop ot'

measurcd

V.. Iinecan't be secn in Fig.3

capacit}' gravitysustaining indLicedby the widcncd shear cracks

develop their uttimate

shear

V,.,con'esponds

remalned

wtts mainly

on the

ACI idealtlexuratstrength intoaccount

'1'9-67-2]). thc thtoretical

V"'hen

T2-33-2D

lhe take

can

[3],The

ot'the 2D-seriesspecimens pattenis

inboth loadingdirections.

superimpo$ed

]ateraltbrces V',nu and

ultimate

Ohno-.traka",afbnnula

inodified

all ot'

the theoreticat

represent

lateral forcesmeasured linesare

of

Fig.2 Crack

she;u'

ot'the

crushing

axial

des,elop its'LLItimate

at

the

axial

¢

peak ]atera!loads. ]ead with n=O.33 is

t'ailufe.The

shortcnings.

strength

butLtse oft]iick

flext;ral strength.

No

131 NII-Electronic Mbrary NII-Electronic Library

Service

Architectural Institute ArchrtecturalInstrtute

of Japan

ofJapan

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thesespecinwns

m

¢

tt'

6

.] O246 DriftratioR(OO1rad)

Dnft ratio R(O O1rad)

.6.4

t

.2

[)

`crTgt67-2Dfcv6eMPaewt=2S

2

6

4

DriftiatioR(OOIrad)

1htnieasLiredc}cttcresponsesol'the2])-striesspeaniens

These mak

't

-lsets .300s T9a32Dfc'=278MPuBlt=28 .4SO .6Lro .6 .4 .2 O]46 .6.4

DrifiratioR{O.Olrad) Fig

30o> 15eeaoere

tt/tttt

o.150-3oe4se.600

g.-"9gs･.

450Z

the

short

reached

imply

observations colunms

theyie]clstrcss

m

tension tillthe end eftests

by sguare

thatconfinement

undei axia]

loadwsth

n=O

33

and

n=O

steel

tube

]s

hard to prevent the

67 ductileenough.

vse

ghoit toTumns

conciete

tubes

ot gteel

with

Blt-43

aiid

with a

B,t=28 arc

])-1 O t'tomshear failuie io

neccssar].

rcgpcctLvell

the inedified Ohno-/U nka"a forniuta[31was adopted in lhis study It can be seen 1'opredictthe ultimatc shcar strength ofthe tubcd short colunms. iormula gives a reasonable lowe: tinllt shear gtTength t'orthetubed colurnnK froniTable 1 (co]uinn piediclion ofthe (13))thattliernodified Ohno-iMakawa V.. had a tnean the coluinns conl'ined by cotu entional ]]eops The rdlio ot' the Xt,,,,, andthe t'iuling m shear although the fi)rmulawas origrnally proposed t'oi value of

1 12and

account

confinement

a standard ell'ect

deviationof O 07 ofthe

steel

tube

The on

measured

the ultlmate

and

catculated

iesutts

tlcxuratstiength

the calculated ilcNuia]strcngths for unconiined (colunins (16)diid (l7)), ilexuret ather than in shcar fronithe columns dre supposed to fiiihn

viewpoint

co]uning of'

as cu

ultmialc

ghoivn

in

Fig 3

and

Table ] aTso

mdTcdte

tnode foi the tubcd pTedicinigt'ailLLie e tnuch sn]alleT lhai] the sheai s" engLhs. This is obviouslN contrcu) sk

cngt+i

the

ittipoitance

As

colunins "hich

to the

ot'taknig

gho"'n

in

n]canK lhat alt ofthe obgeived

itito

Tablc l short

resutts

I32 NII-Electronic Library Service

Architectural Institute of Japan

NII-Electronic Library Service

Architectural Institute ArchrtecturalInstrtute

of Japan Japan

of

1.4

t.4

14

12

1.2

1,2

1

1

1

x"E>x>

es

og

o.K

06

06

06

o.4

o4

o4

O2

02

O,2

e

o

o

O1234S601234S60

DnftratioR(O,O1rad) Fig 6 Comparison

ofthe

envelope

of shear (efi'ect

cLirveg

span

"vau-o-･tpat,9Nkq:votiE:=D 65432l

oO

the

of

iupture

c)bservat)ons shear

span

ratio

Italso the

with

the

patternssho!vn

crack

20

measured

tube,

the

assure

the

and

Fig

m

load V.,. The

rnaximum effect

SO

100

120

2o

4o

4.

of

colunlli

be

it c`m

ao

ne

loo

67 {c)-O

V.,. and

its axial

confinetnent

til] the

capacity

end

Coinbining

test

of

B,t=82 coutd

wlth

these

hnvmg

the column

mtLk.e

ductility

fiexural strength

ultimate

V.. had

the

theultimate

underegtimated

load-canlring pro-ded by thm steel lube

still inaEntam

that

said

suthclent

colunm

ratio ofthe

the steeltube

6o

W ±dth-to-"allthickriess ]atio Blt

gpan ratto)

be seen fromTable2 (Column (11))

can

60

40

ratio B/T Width-to-wal[ thiekriess

tliatthe theoretical

igrio[ance ofconfinernent

4.

654321oo

(b)n=o so

1 S fa11m fiexureand

of

120

ofshear (efeet

drifira"o

porlien ot' the steel

welding

with

tatio)

33

Fig 7 Conipartsonof theultimatc

6

Dnftratio R (O.e1rad)

654321oO

20 40 60 80 100 Width-to-wallthicknessratio B,'t

(a)n=O

12345

DrifiratioR(OO1rad)

a

tnean

value

V.

lateral loadot'the

tubed

by authois'

obtamed

1 02

of

and

method

agreed

deviationofO

a standaid

On the othei

hand.

-33%

f'ailmg in flextire b} 26%

colu]nns

satist'actonly wel]

03

DISCUSSIONONEFFECTOFSHEARSRANRM'10 To

Fig 6 tbrtiiespec]mens

m

seisniic cuiveg ot'the Y-R 1c$ponses ]n tiiepush direc!ion pertoimance ot' tubed columris. envetope For coniparison, the enN'elope tuiveE ot'the 4D-seiies speciniens ieported to axial load with n = O 33 Fig 6. although theaxial toadwas not high.thick steet tube "'rth B,t [atio lesstl]an 43 uag needed to assure

of shear sptui raUe on the

the lnfiucnce

assess

aJ e compared

sutvccted

Ref 2 tue algo plottcdin Fig 6 As ductility to the short coluinns su filcient

shown

m

m

-

1ia-ng a,D

1O

On

hand. thm

thc othei

steel tube

B't

",rth

82

=

could

the

niake

cetumns

with

larg r

a,'D

1S

than

¢

suil'icientl}duct]le

Efi'eets ofthe

definedas the drift ratio at which for specimens

made

from 1

column

5

of

to

4D-series columns 7