Experimental Study on Shear Resistance of SRC Column and Steel Beams Frames Constructed by Simplified Method

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1 Expeimental Study on Shea Reitance of SRC Column and Steel Beam Fame Contucted by Simplified ethod ABSTRACT: A. Kitano 1, Y. Goto 2 and O. Joh 3 1 Aitant Pofeo, Gaduate School of Engineeing, Hokkaido niveity, Sappoo. Japan 2 Pofeo, Gaduate School of Engineeing, Hokkaido niveity, Sappoo. Japan 3 Pofeo emeitu, Gaduate School of Engineeing, Hokkaido niveity, Sappoo. Japan kitano@eng.hokudai.ac.jp, gottu@eng.hokudai.ac.jp, joh@eng.hokudai.ac.jp In thi eeach, expeimental tudie wee caied out 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. Valuable of the expeiment wee teel co-ectional hape of column, confining method of the cove concete and the atio of column hea einfocement. Following conideation wee obtained fom the expeimental eult. 1) Execution method uing the wie meh fo the column wa eaie than that of conventional SRC tuctue. 2) All pecimen except tandad pecimen of conventional SRC and the pecimen uing the wie meh, wide teel flange width and wide teel web depth wee failed in column hea. The tandad pecimen of conventional SRC wa failed in beam-column joint hea. The pecimen uing the wie meh, wide teel flange width and wide teel web depth wa column flexual failue. 3) By inceaing the column teel web depth, hea eitance behavio of the column and confining effect of the concete wee appoximately equal to the tandad pecimen of conventional SRC tuctue. In addition, the maximum hea tength of SC pecimen wae impoved futhe than conventional SRC pecimen, and even the pecimen without hea einfocement had the almot equal hea tength. 4) The hea tength of column in the column-beam fame pecimen wa dependent on the degee of the detuction of the joint. KEYWORDS: SRC tuctue, SC column, hea eitance, hea tength, execution method, hea einfocement, beam-column joint 1. INTRODCTION Recently, contuction numbe of teel encaed einfoced concete (SRC) tuctue 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. In thi eeach, expeimental tudie wee caied out 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. 2. OTLINE OF THE EXPERIENT 2.1. Tet and ateial ed A total of even pecimen wae teted. The dimenion and detail of the pecimen ae hown Fig.1 and Table 1.The pecimen configuation epeented uppe and lowe 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 column that included beam and beam-column joint of a middle floo in a multitoy multi-pan. To make ue that the column hea failue occu pio to any othe failue; the column

2 hea tength wa deigned malle than the flexual and the hea tength of the beam and be-m-column joint. Expeimental vaiable wee method of hea einfocement, co ection of the teel column and hea einfocement atio. All pecimen had column with 2,900mm height and 300mm quae ection, and beam with 2,900mm length and ingle H-ection teel. SRC/S-1-30 wa ued a a tandad fo all pecimen. SRC/S-1-27 wa pepaed in ode to fail in column hea uely. of SC/S-_-W eie wee ued welded wie meh intead of hea einfocement ba. SC/S-30 had no einfocement ba. of SC/S-4 eie had an H-hape teel ection of column. SC/S-4-WC-27 wa le than 0.1% in hea einfocement atio. The column teel ection of SC/S-2-W-30 wa deigned that the flexual pefomance wa impoved by inceaing the ditance between flange in a of co ection equal to tandad pecimen SRC/S-1-30, and that of SC/S-3-W-30 wa deigned the flange width wa widened in addition to it. Table 1. Outline of the pecimen Column Beam Joint *1 teel configation * 2 p w Reinfocement Ba Steel * *2 Steel * p w Reinfocement 12H (%) axial hea 1 1 (%) Ba 2H A SRC/S D10 6φ@ φ@50 32H B SC/S-4-W W3.2φ@50 W3.2φ@ W3.2φ@50 42H CSC/S-4-WC φ W3.2φ@ W3.2φ@150 5H D SRC/S D10 6φ@ φ@50 6H E SC/S-2-W W3.2φ@50 W3.2φ@ W3.2φ@50 7H F SC/S-3-W W3.2φ@50 W3.2φ@ W3.2φ@50 *2 ymbol G SC/S p w : hea ainfocement atio (b) A (a) Stiffne both ide one ide (c) (d) (e) (f) (g) (c) (d) B C D E F, G (a) PL (b) 12-D10(SD685) (c) -6φ(SD345) (d) 3.2φW@50 (e) 3.2φW@150 (f) 4-6φ(SD345) (g) 12-D10(SD345) Section of pecimen G i the ame a pecimen F without einfocement ba Column ection A D B C E F A Column ection B,C D,E,F,G Axial foce Suppoting point (Plu) Suppoting point (inu) Plu loading point inu loading point Joint ection Beam ection Figue 1. Outline of the pecimen

3 Table 2-a. echanical popetie of concete compeive te σ B tenile te σ t compeive tain ε u Young' modulu E 1/3 Young' modulu E 2/3 (N/mm 2 ) (N/mm 2 ) (µ) (kn/mm 2 ) (kn/mm 2 ) A SRC/S B SRC/S C SC/S-2-W D SC/S-3-W E SC/S F SC/S-4-W G SC/S-4-WC Table 2-b. echanical popetie of teel ba Table 2-c. echanical popetie of teel plate SRC/S-1-30 SC/S-2-W-30 SC/S-3-W-30 SC/S-3-30 SRC/S-1-27 SC/S-4-W-27 SC/S-4-WC-27 yield yield Young' teel te tain modulu σ y ε y E (N/mm 2 )(N/mm 2 )(kn/mm 2 ) 3.2φ (W.) φ D10(SD345) φ@50 (W..) φ@150(W..) φ D10(SD685) * W..: welded wie meh SRC/S-1-30 SC/S-2-W-30 SC/S-3-W-30 SC/S-3-30 SRC/S-1-27 SC/S-4-W-27 SC/S-4-WC-27 teel plate yield te σ y yield tain ε y Young' modulu E (N/mm 2 ) (N/mm 2 )(kn/mm 2 ) PL PL PL PL PL PL PL PL PL PL PL The deign tength of the concete wa et at 30N/mm 2 and 27N/mm 2. The aangement of the main column einfocement ba wee 12-D10 fo the SRC/S-eie, and 4-6φ fo the SC/S-4-WC-27. Othe pecimen had no main column einfocement ba. The hea einfocement of SRC/S-eie ued 6φ and othe pecimen ued welded wie meh of 3.2φ. ateial popetie ae hown in Table 2-a, 2-b and 2-c Loading and Intumentation The pecimen wee loaded lateal cyclic hea foce by hoizontal actuato at the top of the column while a contant axial compeion of σ 0 /6 wa applied by vetical actuato, a hown in Fig.2. And uppe beam and lowe beam wee alway kept paallel by fou jack intalled in the end of the beam. The incemental loading cycle wee contolled by toy dift angle, R, defined a the atio of lateal diplacement to the column height, δ/h. The lateal load equence conited of two cycle to each toy dift angle, R of 0.002, 0.005, 0.010, 0.017, 0.026, and 0.05 adian. Duing the tet, the foce, diplacement and einfocement tain wee meaued.

4 actuato fo axial foce actuato fo lateal foce load cell jack ytem fo paallel maintenance pecimen univeal joint load cell eaction teel beam counte weight tet bed Figue 2. Outline of the loading equipment 3. EXPERIENTAL RESLTS AND DISCSSIONS 3.1. Cicumtance of Failue The cicumtance of the failue fo all pecimen afte teting ae hown in Photo 1. SRC/S-1-30 failed uppe and lowe joint hea. An initial flexual cack appeaed in the column end and beam-column joint duing the fit cycle loading and an initial hea cack appeaed in the column and joint duing the econd cycle loading. Afte that, hea cack makedly appeaed in mot pat in the joint by the fifth cycle. The widening of the hea cack of the joint wa intenified afte the eventh cycle, and the concete cove came off in place. The hea cack of the column, howeve, wa not widened. On the othe hand, pecimen SRC/S-1-27 failed hea in the end of column. An initial hea cack appeaed in the column and joint at R (toy dift angle) =0.002 to adian. Afte that, the widening of the hea cack and cuhing in the end of column wee intenified at R=0.01 to adian, and the hea einfocement ba of column yielded. Afte R=0.037 adian, cove concete of column wa flaked off intenively. SC/S-2-W-30 failed column hea. An initial hea cack appeaed in the column at R=0.005 adian. At R=0.01 adian, the welded wie meh of joint and column wee yielded and the flexual cack appeaed in the end of column and the widening hea cack in the column wee intenified. Afte maximum tength, the flaking of the cove concete occued in the whole column, the teel flange of column wa baed, and the cutting off of the wie meh wa alo obeved. Fo SC/S-3-W-30, an initial hea cack appeaed in the column at R=0.005 adian. At R=0.01 adian, the welded wie meh of joint and column wee yielded and the flexual cack appeaed in the end of column and the widening hea cack in the column wee emakable. Howeve, the ability of the jack eached it limitative at R=0.026 adian, and the expeiment wee finihed. SC/S-3-30 failed hea in the column. An initial hea cack appeaed in column at R=0.005 adian. any hea cack appeaed and widened in the whole column. Afte that, the cove concete wa flaked in the whole column and the buckling of teel flange wa occued in the end of column. Fo SC/S-4-W-27, in the appeaance, it wa the flexue factue of the end of column. An initial flexual cack and an initial hea cack of joint and column appeaed at R=0.005 adian.

5 otly, the flexual cack had gown and widened in the end of column. Afte that, howeve, the widening of hea cack of the joint wa emakable. Afte maximum tength, the welded wie meh wa baed in the end of column and the buckling and cutting off of welded wie meh wee occued, and the concete cove came off in the joint. SC/S-4-WC-27 failed hea in the column. An initial flexual cack and hea cack appeaed in the column and joint at R=0.005 adian. Afte that, joint hea cack appeaed and had gown emakable, and the cone ba in the column and welded wie meh in the joint wee yield. Afte maximum tength, the widening of the hea cack of the joint wa intenified, and the welded wie mehe in the column wee baed, and the buckling and the cutting off of the wie meh wa alo obeved. SRC/S-1-30 SC/S-2-W-30 SC/S-3-W-30 SC/S-3-30 SRC/S-1-27 SC/S-4-W-27 SC/S-4-WC-27 Photo 1. The cicumtance of the failue 3.2. Load v. Diplacement Relationhip Skelton cuve of all pecimen, which wee obtained fom the inteaction cuve of the column hea foce C and toy defomation angle C R, ae hown fo compaion in Figue 3 to 5.

6 3.2.1 Effect of the hape of the column teel ection by co H-ection (Figue 3) The effect of the hape of the column teel ection can be obeved by compaing SRC/S-1-30, SC/S-2-W-30, SC/S-3-W-30 and SC/S The initial tiffne wa almot ame on fou pecimen, and the maximum hea tength wa alo almot ame except fo SC/S-3-W-30. In pite of the diffeence of the membe, which failed SC/S-2-W-30 and SRC/S-1-30, the imila behavio wa poved in C- C R elationhip. Theefoe, it wa poven that to obtain pefomance of tuctue equal to uual SRC tuctue wa poible uing the wie meh by enlaging the teel co ection of column. Fo SC/S-3-W-30, the hea te kept iing afte tiffne eduction, and it eached peuization limit of the actuato fo lateal foce at R= adian, and the expeiment wa finihed. Howeve, the ie of the hea te wa a flat almot, and the hea te at R= adian wa conideed maximum tength. By inceaing the column teel web depth, hea eitance behavio of the column and confining effect of the concete wee appoximately equal to C(kN) 400 CR(x10-3 ad.) SRC/S-1-30 SC/S-2-W-30 SC/S-3-W-30 SC/S-3-30 the tandad pecimen, SRC/S In addition, the maximum hea tength of SC pecimen wae impoved futhe than conventional SRC pecimen, and even the pecimen without hea einfocement had the almot equal hea tength Figue 3. Skelton cuve (Effect of the hape of the column teel ection by co H-ection) Effect of the hape of the column teel ection between co H-ection and ingle H-ection (Figue 4) The effect of the hape of the column teel ection between co H-ection and ingle H-ection can be obeved by compaing SC/S-4-W-27, SC/S-2-W-30 and SC/S-3-W-30. The initial tiffne wa almot ame on thee pecimen. It wa obeved a diffeence of the hea te afte aound C R=0.02 adian, and fo the maximum hea tength of SC/S-3-W-30, SC/S-4-W-27 and SC/S-2-W-30 wee epectively eduction of 30kN and 40kN. The eaon why the diffeence occued at the maximum tength wa not the exitence of the tanvee flange, becaue the concete tength of SC/S-3-W-30 wa bigge than SC/S-4-W-27 about 10N/mm 2. And, it eemed to hold the hea te loweing by the tanvee flange eticting the coe concete, becaue in compaion with the looped fom of SC/S-2-W-30 and it of SC/S-4-W-27 afte CR=0.026 adian, SC/S-4-W-27 gadually changed in the pinching fom, theefoe SC/S-4-W-27 wa fuifom. Howeve, SC/S-2-W-30 and SC/S-4-W-27 wa ame behavio in the lage diplacement. It eem to be the eaon why teel buden hea te and coe concete buden hea te uounded in the teel wee almot equal. C(kN) CR(x10-3 ad.) SC/S-4-27 SC/S-2-W-30 SC/S-3-W-30 Figue 4. Skelton cuve (Effect of the hape of the column teel ection between co H-ection and ingle H-ection)

7 3.2.3 Effect of the hea einfocement atio of the welded wie meh (Figue 5) The effect of the hea einfocement atio of the welded wie meh can be obeved by compaing SC/S-4-W-27 and SC/S-4-WC-27. Stiffne eduction alo appeaed both pecimen nea CR=0.007 adian. SC/S-4-W-27 became CR=0.017 adian with the maximum tength, and SC/S-4-WC-27 became C R =0.01 adian with the maximum tength. A a facto of the maximum tength eduction, SC/S-4-W-27 wa mainly the poge of flexue factue and collape in the column edge, and SC/S-4-WC-27 wa the flexue failue ove column full face. Fom thi fact, though thee wa a function of the hea einfocement on the welded wie meh, it wa poven to be inufficient fo etaining the ductility capacity in p w =0.1% o le that the quantity i egulated in the SRC tandad. C(kN) CR(x10-3 ad.) SC/S-4-W-27 SC/S-4-WC-27 Figue 5. Skelton cuve (Effect of the hea einfocement atio of the welded wie meh) 3.3. ltimate Shea Stength of the Column The calculated value of the tength of the column and beam-column joint fo all pecimen wee calculated fom the AIJ-SRC Standad equation, the expeimental and the calculated value ae hown in Table 4. The expeimental and calculated value wee compaed fo the column hea foce. The AIJ-SRC tandad equation ae hown in Table 3. ltimate hea tength of column C u = + teel RC = min( b =, b = Σ( / h ) = 2 / h e ) ( D 2 t ) σ / 3 ctw 2 C c f Cw y e ltimate hea tength of joint ( l mc d) h cal. J u = ju / 1 B d ju = j u / B d 1.2 V σ y j u = cve ( j F j δ + w p w σ y ) + 3 u = min( 1, 2, b ) ltimate flexual tength 1 = 7 / 8 c b c d(0.5f α + 0.5pw w σ y) C u =2C / he 2 = 7 / 8 c b c d( F b / cb + pw w σ y) C = = Σ( / h ) = 2 / h + b u Table 3. The AIJ-SRC tandad equation e :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) wσy:yield te of hea einfocement(n/mm 2 ) F:hea tength of concete(n/mm 2 ) b :effective width by teel flange(mm) c:eduction coefficient *c= pc e teel RC RC ju :ultimate hea tength of joint(n) j 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 ) teel The calculated value of column hea by SRC tandad equation had oveetimated the expeimental value, when calculated value wee compaed with expeimental value in all tet pecimen except fo SRC/S Following two point wa conideed a thi caue. The fit, the calculated value of the hea tength haed

8 by the RC of the SRC tandad wa expeimental equation which applied the RC tandad, which wa equied by the column hea expeiment with the conventional loading tub, and it i diffeent fom the pecimen in thi tudy. The econd, thee wa the epot that the column hea tength wa educed by the diffeence between the damage cicumtance of the joint. Then, a a eult of examining the effect of hea capacity magnification facto of the beam-column joint on column hea capacity calculation equation, it wa poven that the expeimental value had been oveetimated, a hea capacity magnification facto of beam-column joint i malle. Still, it wa claified that thee wa no effect of the joint damage on the column hea capacity, if the joint hea magin i ove Table 4. Expeimental and calculated value on ultimate tength maximum tength (kn) calculate ultimate tength by AIJ- SRC tandad(kn) joint hea column hea column flexual exp.c u / cal. * ** joint column hea hea capacity magnification facto failue poition exp.c u cal.j u cal.c u cal.c bu cal.j u cal.c u A SRC/S column B SC/S-4-W column C SC/S-4-WC column D SRC/S joint E SC/S-2-W column F SC/S-3-W column G SC/S column cal. J cal. C u u 4. CONCLSIONS The following obevation wee obtained fom thi expeimental tudy of SRC tuctue. 1) Execution method uing the wie meh fo the column wa eaie than that of conventional SRC tuctue. 2) All pecimen except tandad pecimen of conventional SRC and the pecimen uing the wie meh, wide teel flange width and wide teel web depth wee failed in column hea. The tandad pecimen of conventional SRC wa failed in beam-column joint hea. The pecimen uing the wie meh, wide teel flange width and wide teel web depth wa column flexual failue. 3) By inceaing the column teel web depth, hea eitance behavio of the column and confining effect of the concete wee appoximately equal to the tandad pecimen of conventional SRC tuctue. In addition, the maximum hea tength of SC pecimen wae impoved futhe than conventional SRC pecimen, and even the pecimen without hea einfocement had the almot equal hea tength. 4) The hea tength of column in the column-beam fame pecimen wa dependent on the degee of the detuction of the joint. REFERENCES 1. Achitectual Intitute of Japan (2001), Standad fo Stuctual Calculation of Steel Reinfoced Concete Stuctue, (in Japanee) 2. Iizuka S., Kaamatu T., and Noguchi H. (1997), Study on The Aeimic Pefomance of ixed Fame Stuctue. Jounal of tuctual and contuction engineeing. Tanaction of AIJ No.497, (in Japanee)