Experimental Study on Shear Resistance of Steel Beams and SC Column Joints Constructed by Simplified Method

Transcription

1 Expeimental Study on Shea Reitance of Steel Beam and SC Column Joint Contucted by Simplified Method A. Kitano Maebahi Intitute of Technology, Japan Y. Goto & K. Nihimua Hokkaido niveity, Japan SMMARY: In thi eeach, expeimental tudy wa caied out on hea eitance of beam-column joint of the new tuctue. The new tuctue wa concete encaed teel (SC) tuctue that it emoved the einfocing ba fom the SRC tuctue and ued the welding wie meh. The pecimen wee beam-column joint coniting of SC column and teel beam. The column and beam-column joint ued the welding wie meh o that the cove concete might not delaminate and the implification of column main ba and hea einfocement. Following conideation wee obtained fom the expeimental eult. Thee wa no effect of the teel co-ectional hape of column in ultimate hea tength of the beam-column joint, and they could be evaluated by the SRC tandad equation of AIJ (Achitectual Intitute of Japan). Howeve, thee wa a diffeence in the defomability of the beam-column joint. Keywod: concete encaed teel tuctue, beam-column joint, ultimate hea tength, yield mode of teel 1. INTRODCTION Recently, contuction numbe of Steel and Reinfoced Concete (SRC) Stuctue decline in Japan. Becaue, the tuctue deign method of SRC i complicated and the pocee of execution wok ae abounding fo it contuction. Howeve, SRC tuctue ae moe excellent fo ductility capacity than the RC tuctue, and the damage of the SRC tuctue wae light in Hyogo-ken Nanbu Eathquake. Autho caied out the expeimental tudie in ode to develop the new tuctue ytem uing teel and concete with execution method that i eaie than the SRC tuctue and with eathquake eitant pefomance that i equivalent to the SRC tuctue, and the new tuctue which eplaced the SRC tuctue wa popoed. The new tuctue wa concete encaed teel (SC) tuctue that it emoved the einfocing ba fom the SRC tuctue and ued the welding wie meh. Howeve, thee wa the unexpected detuction in the beam-column joint tongly deigned futhe than the column. Then, in thi eeach, expeimental tudy wa caied out on hea eitance of beam-column joint of the new tuctue. The pecimen wee beam-column joint coniting of SC column and teel beam. The column and beam-column joint ued the welding wie meh o that the cove concete might not delaminate and the implification of column main ba and hea einfocement. 2. OTLINE OF THE EXPERIMENT 2.1. Tet Specimen and Mateial ed A total of fou pecimen wae teted. The dimenion and detail of the pecimen ae hown Figue 2.1. and Table 2.1..The pecimen configuation epeented beam and column egment between inflection point in a fame ubjected to lateal loading. The contaction cale of the tet pecimen wa about 1/2 of an SRC tuctue on the aumption of beam-column joint of a middle floo in a multi-toey multi-pan. To make ue that the beam-column joint hea failue occu pio to any othe failue; the beam-column joint hea tength wa deigned malle than the flexual and the

2 hea tength of the beam and column. Howeve, only pecimen became the column failue, when it wa calculated at the eal tength of the ued mateial. Expeimental vaiable wee column co-ectional hape and yield mode of the column teel. All pecimen had column with 1,6mm height and 3mm quae ection, and beam with 2,9mm length and wide flange hape. All pecimen contained wide flange hape teel fo the column and thee i no column main einfocement ba and hea einfocement. Intead, the welding wie meh wa aanged in ode to might not delaminate of the cove concete. Though the co ection of the column teel wa almot ame fo pecimen and pecimen, the teel flange width wa diffeent. Specimen and pecimen wee alo ame. The diffeence between pecimen and pecimen and between pecimen and pecimen wee the teel flange thickne of the column and teel web thickne of the beam-column joint. The failue mode of column teel wa hea failue except pecimen. The failue mode of column teel wa flexue fo pecimen. WM3.2φ@ (f.t.=12) (f.t.=9) (f.t.=6) (f.t.=4.5) column ection (f.t.:fange thickne) joint ection tiffene (both ide) tiffene (one ide altenately) loading point (plu cycle) loading point (minu cycle) 16 joint ection beam ection column ection axial loading point uppoting point (plu) uppoting point (minu) Table 2.1. Detail of the pecimen p w * 2 Column Figue 2.1. Outline of the pecimen Beam p w *2 *1 teel configation Specimen Welded wie Steel web thickne A:BH Steel *1 Steel *1 (%) meh (%) (mm) B:BH A E C:BH B E D:BH φ@5.11 C F E:BH D F F:BH *2 ymbol; p w : hea ainfocement atio Joint

3 The deign tength of the concete wa et at 27N/mm 2. The aangement of the welded wie meh wee Mateial popetie ae hown in Table 2.2., 2.3. and Table 2.2. Mechanical popetie of concete Specimen compeive te tenile te compeive tain Young' modulu Young' modulu σ B (N/mm 2 ) σ t (N/mm 2 ) ε u (µ) E 1/3 (kn/mm 2 ) E 2/3 (kn/mm 2 ) Table 2.3. Mechanical popetie of welding wie meh Specimen teel yield te σ y yield tain ε y modulu E Young' (N/mm 2 ) (N/mm 2 ) (kn/mm 2 ) 3.2f@5 (W.M.) Table 2.4. Mechanical popetie of teel plate Specimen teel plate yield te σ y yield tain ε y modulu E Young' (N/mm 2 ) (N/mm 2 ) (kn/mm 2 ) PL PL PL PL PL PL Loading and Intumentation Loading aangement i chematically hown in Figue The incemental foced diplacement wa given to the pecimen at the top of the column cyclically duing the application of column axial te of σ B /6. The incemental loading cycle wee contolled by toy dift angle, R c, defined a the atio of lateal diplacement to the column height, δ/h. The lateal load equence conited of two cycle to each toy defomation angle, R c of.2,.5,.1,.17,.26,.37 and.5 adian. Duing the tet, the foce, diplacement and einfocement tain wee meaued.

4 eaction teel beam fo axial foce actuato fo axial foce load cell actuato fo lateal foce pecimen univeal joint load cell eaction teel beam counte weight tet bed Figue 2.2. Outline of the loading equipment 3. EXPERIMENTAL RESLTS AND DISCSSIONS 3.1. Cicumtance of Failue The cicumtance of the failue fo all pecimen afte teting ae hown in Photo All pecimen failed in beam-column joint hea. The geneal poce of cacking wa a follow. An initial flexual cack and a hea cack appeaed in column and in beam-column joint duing the econd cycle loading (R c =.5 adian). Afte that, fo pecimen and pecimen, hea cack makedly appeaed in mot pat of the joint by the fouth cycle loading (R c =.1 adian), and at the ixth cycle loading (R c =.17 adian), the teel web plate, the teel flange plate and the welded wie meh of beam-column joint wee yielded. Howeve, fo pecimen, the teel web plate and welded wie meh of the beam-column joint wee yielded at the econd cycle loading (R c =.5 adian). Afte that, the teel flange plate of beam-column joint wa yielded at the ixth cycle loading (R c =.17 adian). Fo pecimen, the teel web plate and welded wie meh of beam-column joint wee yielded at the fouth cycle loading (R c =.1 adian). The teel flange plate of the beam-column joint wa yielded duing the ixth cycle loading (R c =.17 adian).and the delaminating of the concete in the cente of joint and in the column end wa emakably obeved unde the eighth cycle loading (R c =.26 adian). Afte maximum tength, fo pecimen and pecimen, the delaminating of the concete in the cente of joint and in the column end wa emakably obeved. And, the widening of the bond litting cack of the column teel flange wa alo emakable in pecimen. In addition, the flaking of the concete in the joint of pecimen wa le

5 than that of pecimen, becaue, the concete volume which the teel uound in the beam-column joint wa big. Thee wee the cicumtance of failue which vaied in the cack obevation plane on pecimen. It eemed to be becaue the te tanmiion to the beam-column joint diffeed in outh face and noth ide by that pecimen caued by tenile yield of the column flange out-of-plane defomation and that the teel flange of the beam-column joint in outh face buckled. Fo pecimen, the cove concete exfoliated with the collape of the concete at the column end, and the welding wie meh wa expoed. The damage of the concete of the beam-column joint of pecimen wa moe intene than that of pecimen. Theefoe, fo pecimen, the poof te haing of teel and welding wie meh inceaed. Afte all, pecimen became the flexual failue of the column, though the beam-column joint hea failue wa aumed in the deign, and pecimen became the hea failue of the beam-column joint, though the column hea failue wa aumed in the deign. Fom the joint cack ituation at R c =.5 and.1 adian, the joint cack numbe of (the yield mode of column teel wa the hea) wa moe abounding than that of (the yield mode of column teel wa the bending). And, in welding wie meh tain ditibution of the beam-column joint cente, pecimen wa highe than pecimen. Theefoe, the diffeence of the yield mode of the column teel eemed to affect the damage of the beam-column joint at R c =.1 adian, and in the tuctual deign, it eem to be poible to educe the damage of the beam-column joint by chooing that the yield mode of the column teel i bending. Photo 3.1. Cicumtance of failue 3.2. Load v. Diplacement Relationhip Skeleton cuve of all pecimen, which wee obtained fom the inteaction cuve of the column hea foce C and toy defomation angle R c, i hown fo compaion in Figue And, the inteaction cuve of the column hea foce C and toy defomation angle R c of all pecimen ae hown in Figue All pecimen alo howed the fuifom hyteei of good enegy aboption. And the diffeence hadly could be obeved in all pecimen in the hape of the inteaction cuve. The effect of the hape of the column teel ection can be obeved by compaing and. Both pecimen howed the behavio which wa almot imila up to maximum tength, c(kn) Rc(x1-3 ad.) Figue 3.1. Skelton cuve

6 and it became the maximum tength at R c =.17adian, and the tength gently loweed aftewad. The tength deceae afte the maximum tength of pecimen wa bigge than that of pecimen. A thi eaon, the poof te hae of the concete eemed to deceae on pecimen in which the concete volume uounded by the teel in the beam-column joint wa mall, ince the flaking of the concete afte the maximum tength wa emakable. Fom the above fact, the teel co-ectional hape eem to affect the tength eduction afte the maximum tength. In the compaion of pecimen and pecimen, pecimen came to the maximum tength at R c =.17adian, while pecimen came to the maximum tength at R c =.26adian. A the facto which became the maximum tength, yield of hoizontal welding wie meh einfocement of the column end poition, vetical welding wie meh einfocement of the beam-column joint, the teel flange of beam-column joint and the teel web wee conideed pecimen, and the yield of vetical welding wie meh einfocement, teel flange, teel web in the beam-column joint wee conideed pecimen. c(kn) kelton cuve c(kn) kelton cuve Rc(x1-3 ad.) Rc(x1-3 ad.) [Specimen ] [Specimen ] c(kn) kelton cuve c(kn) kelton cuve Rc(x1-3 ad.) Rc(x1-3 ad.) [Specimen ] [Specimen ] Figue 3.2. Relationhip of column hea foce C - toy defomation angle R c

7 3.3. ltimate Shea Stength of the Beam-Column joint The calculated value of the ultimate tength of the beam-column joint fo all pecimen wee calculated by the AIJ-SRC Standad equation (AIJ 1) and efeence (AIJ 211) equation. The expeimental and the calculated value ae hown in Table 3.1., and ued equation ae hown in Table The calculate value of ultimate tength of column in Table 3.1. ( cal.3 and cal.4 ) wee evied value which multiplied the coefficient in ode to convet the value by Table 3.2. into median value. Table 3.1. Expeimental and calculated value on ultimate tength pecimen expeimental value of maximum tength AIJ-SRC tandad (AIJ 1) beam-column joint calculate value of ultimate tength efeence (AIJ 211) column exp. (kn) cal.1 (kn) cal.2 (kn) cal.3 (kn) cal.4 (kn) exp./cal.4 SC/S-4j-W SC/S-5j-W SC/S-8j-W SC/S-9j-W hea flexue Table 3.2. Equation of calculation of hea tength ltimate hea tength of joint AIJ-SRC Standad (AIJ 1): cal.1 j cal. J M u u ( l mc d) h = ju / 1 B d ju = j M u / B d 1.2 V σ y = cve ( j F j δ + wp w σ y ) + 3 RC R/C teel Steel ltimate hea tength of column: cal.3 C u = + teel RC = min( b =, b = Σ( M / h ) = 2 M / h e ) ( D 2 t ) σ / 3 ctw 2 C c f Cw y u = min( 1, 2, b ) 1 = 7 / 8 c b c d(.5f α +.5pw wσ y) 2 = 7 / 8 c b c d( F b / cb + pw wσ y) = Σ( M / h ) = 2 M / h b u e e e Refeence (AIJ 211) equation: cal.2 ( ) M = M + min M, M j u i o a o T Symbol; ju :ultimate hea tength of joint(n) jm u :ultimate flexual moment of joint(n mm) Bd:ditance between teel flange cente of gavity (mm) mcd:ditance between main ba cente of gavity (mm) cv e :volume of R/C of joint(mm 3 ) jδ:coefficient of hape of joint V:volume of teel of joint(mm 3 ) im :moment of inide element of joint (N mm) om a :moment of outide element of joint by ach model (N mm) om T :moment of outide element of joint by tu model (N mm) wσ y :yield te of hea einfocement (N/mm 2 ) ltimate flexual tength: cal.4 C Mu =2C M / he C M = M + M teel RC :hea tength of teel (N) b :flexual tength of teel (N) 1 :hea tength (N) 2 :bond plitting tength (N) b :flexual tength of R/C (N) F :hea tength of concete (N/mm 2 ) b :effective width by teel flange (mm) c :eduction coefficient *c= pc

8 In compaion with expeimental value and calculated value by AIJ-SRC tandad (AIJ 1), fo pecimen and pecimen, the ultimate hea tength of beam-column joint of expeimental value had oveetimated the calculated value about 13%-17%. Theefoe, it eemed that the calculated value etimated the expeimental value accuately. Howeve, fo pecimen and pecimen, the expeimental value had undeetimated each calculated value. In pecimen, the maximum tength eemed to be hea failue of beam-column joint along the etimation in the deign. In pecimen, it eemed to be hea failue of beam-column joint in pite of the hea failue of the column in the deign, ince the joint web plate yielded and the widening of the hea cack wee emakably obeved befoe maximum tength. Fo pecimen, the eaon why the expeimental value wa lowe than calculated value eemed to be a collape of concete at the column end and the widening of which the hea cack of the joint wae emakable. Fo pecimen, the eaon why the expeimental value wa lowe than calculated value eemed to be alo the widening of which the hea cack of the joint wae emakable. Theefoe, it i neceay to popoe the calculation equation with the good accuacy in popotion to the failue type in futue. The diffeence between equation cal.1 and equation cal.2 ae whethe o not it conide the teel flange of the joint yield, and whethe o not it conide the te tanfe mechanim of beam-column joint. So, in compaion with expeimental value and calculated value cal.2, the expeimental value ageed with calculated value on pecimen in which the teel flange of the joint yielded. Then, it wa a good evaluation in all pecimen except pecimen. Examination will be neceay in futue, becaue the eaon why the hea tength of the joint of pecimen cannot evaluate by the both equation wa not poven. 4. CONCLSIONS The following obevation wee obtained fom the lateal load eveal tet pefomed on beam-column joint pecimen. 1) The diffeence of the yield mode of the column teel affected the numbe of joint cack and tain of the hoizontal welding wie meh at the toy defomation angle R c =.1adian. Theefoe, it eemed to be poible to hold the damage of the joint by making the yield mode of the column teel in the deign with the flexue. 2) It wa bette the accuacy in the evaluation of the ultimate hea tength of beam-column joint of equation by efeence (AIJ 211) than equation by AIJ-SRC tandad (AIJ 1). REFERENCES Achitectual Intitute of Japan (1), Standad fo Stuctual Calculation of Steel Reinfoced Concete Stuctue, Achitectual Intitute of Japan (in Japanee) Achitectual Intitute of Japan (211), Ste Tanfeing Mechanim and Reitance Mechanim of Steel-Reinfoced Concete Joint, Achitectual Intitute of Japan (in Japanee) A. Kitano, Y. Goto and O. Joh (8), Expeimental Study on Shea Reitance of SRC Column and Steel BeamFame Contucted by Simplified Method, The 14 th Wold Confeence on Eathquake Engineeing, Pape ID: