土木工程外文文獻(xiàn)翻譯--鋼筋混凝土框架異型節(jié)點(diǎn)抗震性能試驗(yàn)研究

1、Experimental research on seismic behavior of abnormal jointin reinforced concrete frameAbstract :Based on nine plane abnormal joint s , one space abnormal joint experiment and a p seudo dynamic test of a powerplant model

2、 , the work mechanism and the hysteretic characteristic of abnormal joint are put to analysis in this paper. Aconception of minor core determined by the small beam and small column , and a conclusion that the shear capac

3、ity of ab2normal joint depends on minor core are put forward in this paper. This paper also analyzes the effect s of axial compres2sion , horizontal stirrup s and section variation of beam and column on the shear behavio

4、r of abnormal joint . Finally , theformula of shear capacity for abnormal joint in reinforced concrete f rame is provided.Key words : abnormal j oint ; minor core ; seismic behavior ; shear ca paci t yCLC number :TU375.

5、4 ; TU317. 1 Document code :A Article ID :100627930 (2006) 0220168210 1 Int roduction For reinforced concrete f rame st ructure , t he joint is a key component . It is subjected to axial comp ression , bendi

6、ng moment and shear force. The key is whet her the joint has enough shear capaci2 ty. The Chinese Code f or S eismic Desi gn of B ui l di ngs ( GB5001122001) adopt s the following formula to calculate t he shear capaci

7、ty of the reinforced concrete f rame joint . V j = 1. 1ηj f t bj h j + 0. 05ηj N bj bc + f yv Asvj hb0 - a′s s (1) Where V j = design value of t he seismic shear capacity of the joint core section ; ηj = influential coef

8、ficient of t he orthogonal beam to the column ; f t = design value of concrete tensile st rength ; bj = effective widt h of the joint core section ; hj = dept h of the joint core section , Which can be adopted as t he de

9、pth of the column section in t he verification direction ; N = design value of axial compression at t he bot tom of upper column wit h considering the combi2 nation of the eart hquake action , When N > 015 f c bc hc ,

10、 let N = 0. 5 f c bc hc ; bc = widt h of t he column section ; f yv = design value of t he stirrup tensile st rengt h ; Asvj = total stirrup area in a set making up one layer ; hb0 = effective dept h of t he beam. If t h

11、e dept h of two beams at the side of t he joint is unequal , hb0 = t he average depth of two beams. a′s = distance f rom the cent roid of the compression beam steel bar to the ext reme concrete fiber . s = distance of t

12、he stirrup . Eq. 1 is based on t he formula in t he previous seismic code[1 ] and some modifications made eavlicr and it is suit2 able to the normal joint of reinforced concrete f rame , but not to t he abnormal one whic

13、h has large different in t he section of t he upper column and lower one (3 600 mm and 1 200 mm) , lef t beam and right beam (1 800 mm and 1 200 mm) . The shear capacity of abnormal joint s calculat2 ed by Eq. 1 may caus

14、e some unsafe result s. A type of ab2 normal joint which of ten exist s in t he power plant st ruc2 t ure is discussed ( see Fig. 1) , and it s behavior was st ud2 ied based on t he experiment in t his paperbond graduall

15、y permeated towards t he internal core , enhancing t he burden of t he diagonal compression bar mechanism and accelerates the compression failure of concrete. Fig. 4 shows t he p hotos of typical damaged joint s. A p se

16、udo dynamic test of space model of power plant st ruct ure was carried out to research t he working behavior of t he abnormal joint s in re2 al st ructure and the seismic behavior of st ructure. Fig. 5 shows the p hoto o

17、f model . The test includes two step s. The fir st is the p seudo dynamic test . At t his step , El2Cent ro wave is inp ut and the peak acceleration varies f rom 50 gal to 1 200 gal . The seismic response is measured. Th

18、e second is t he p seudo static test . The loading can’t stop until t he model fail s.Fig. 7 Minor core The experiment shows t hat t he dist ribution and development of t he crack is influenced by t he rest rictive eff

19、ect of the ort hogonal beam , and t he crack of joint core mainly dist ributes under t he orthogonal beam ( see Fig. 6) , which is different f rom t he result of t he plane joint test , but similar to J 4210. 3. 3 Analy

20、sis of test results 3. 3. 1 Mechanical analysis In t he experiment , t he location of the initial crack of t he exterior joint and the crushed position of concrete both appear in the middle of t he joint core , and t he

21、 position is near t he centerline of t he upper col2 umn. The initial crack and crushed position of t he concrete of the interior joint both appear in t he mi2 nor core ( see Fig. 4 ,Fig. 7) . For interior abnormal joint

22、 t he crack doesn’t appear or develop in t he ma2 j or core out side of the mi nor core until t horough cracking takes place , while t he crack seldom appears in t he shadow region ( see Fig. 7) as the joint fail s. Th

23、erefore , for abnormal joint , t he shear capacity of t he joint core depends on t he properties of t he mi nor core , namely , on t he st rengt h grades of concrete , t he size and the reinforcement of t he mi nor cor

24、e , get t he effect of t he maj or core dimension can’t be neglected. Mechanical effect s are t he same will that of t he normal joint , when t he forces t ransfer to t he mi2 nor core t hrough column and beam and reinf

25、orcement bar . Therefore , t he working mechanisms of nor2 mal joint , including t russ mechanism , diagonal compression bar mechanism and rest rictive mechanism of stirrup , are also suitable for mi nor core of t he a

26、bnormal joint , but their working characteristic is not symmet rical when the load rever ses. Fig. 8 illust rates t he working mechanism of t he abnormal joint . When t he load t ransfer to mi nor core , t he diagonal co

27、mpression bar area of mi nor core is bigger t han normal joint core2composed by small column and small beam of abnormal joint , which is due to t he compressive st ress diff usion of concrete compressive region of the be

28、am and column , while at t he same time t he compression carried by the diagonal compression bar becomes large. Because t he main part of bond force of column and beam is added to t he diagonal comp ression bar but cont

29、 rasting wit h t he increased area of diagonal compression bar , t he increased action is small . The region in the maj or core but out of the mi nor core has less st ress dist ribution and fewer cracks. The region can