1 Fig. 1 Perspective view of New CCTV Building 13008mm 2, 2811% ( ) 6, HRB400, 1187mm 2, 216% C60, 32095mm 2, Q345, 2 4,, Q345, Q390C, 2, 1 Q235, 5mm

29 3 Vol129, No13 2008 6 Journal of Building Structures June 2008 : 100026869 (2008) 0320031209 SRC 1, 1, 1, 1, 2, 2, 2 (1., 200092; 2., 200002) : SRC 30%, SRC 9,, N P 2M P SRC, SRC ; N P 2M P SRC : ; ; ; ; : TU3751302 TU31711 : A Experimental study on hysteretic behavior of SRC columns with high ratio of core steel CHEN Yiyi 1, WANG Haisheng 1, ZHAO Xianzhong 1, HU J ingli 1, WANG Dasui 2, J IANG W enwei 2, BAO L ianjin 2 ( 1. College of Civil Engineer, Tongji University, Shanghai 200092, China; 2. East China A rchitectural Design and Research Institute Co. L td, Shanghai 200002, China) Abstract: The SRC columns used in New CCTV Building have a high structural steel ratio up to 30 percentage and high strength steel has been adop ted. To study the hysteretic behavior, a series of p seudo static tests was performed in two phases. In this paper, nine specimens of them were reported. Testing p rocess and phenomena were described, and the hysteretic curves, ductility ratio and loading capacity were analyzed. The axial force and moment relation based on p lastic theory was calculated and compared with the test results. It is shown that the SRC column with large ratio of steel has good seism ic performance and deformability, and is largely different from those of SRC member with ordinary steel ratio. The method for calculating the interactive strength of axial force and flexural moment by ultimate state is conservative. Keywords: steel reinforced concrete column; high ratio of steel; experiment; ductility; hysteretic loop 0 ( CCTV ), 234m, 6, 14 ( 1),, ( 2), 30%, ( JGJ 138 2001 ) ( YB 9082 97) ( 10% 15% ) [ 122 ], 3% 10% [ 3210 ], 1 CCTV, CCTV : (1955 ),,,, : 2008 3 31

1 Fig. 1 Perspective view of New CCTV Building 13008mm 2, 2811% ( ) 6, HRB400, 1187mm 2, 216% C60, 32095mm 2, Q345, 2 4,, Q345, Q390C, 2, 1 Q235, 5mm 25mm, 200mm; 10mm 50mm, 100mm E s A s / E c A c =2131; E s I s / E c I c =1159 ( ), E A I ; s c ( ),, L = 1200mm, 2 Fig. 2 Structure of external tube and the location of : column to be tested (1) : Q390C, C60 (2) ( 25% ),, (3),,, (4) ( ),, 5,, 4 2 211,,, (1), 1, 1 /6167, 3a 12mm, 3 Fig. 3 D imension of specimens 32

4 Fig. 4 Steel p roperty curves (2) 7, 1, 1 /7114, 3b 14mm, 11760mm 2, 3012% ( ) ; 6, HRB400, 1244mm 2, 312% ; C60, 25973 mm 2 ; 2, 1 Q235, 415mm 24mm, 120mm; 8mm 42mm, 65mm E s A s / E c A c =2158; E s I s / E c I c =1161 ( ), :, ; 1 Ta b le 1 Info rm a tio n o f sp ec im e n s f cu /MPa ( ) ( ) n SRCF 21 5714 01317 SRCF 21 5510 01567 SRCP 21 6718 01551 SRCP 22 6415 01551 SRCP 21 7610 01468 SRCP 22 7817 01468 SRCP 21 7118 01393 SRCP 22 7319 01393 SRCP 21 7113 01299 2 Tab le 2 M echa n ica l p rop e rtie s o f ste e l in sp ec im e n f y f u N mm 22 N mm 22 N mm 22 N mm 22 352 538 31% 436 581 27% 362 544 32% 436 581 27% f y f u, L = 600mm, ( 6b), 212 5, 5 Fig. 5 Test set2up,, 6a,,, (, ),, ( 5 1),, ( 6a), 6a M = PL /4 M = P L /4,, 5b 33

: ( 6b ) ; ( 6b 6 Fig. 6 Sketch map of test setup and deformation ), ( 6c, 311, ),,, ;,,,, ;,,,,, 7a,,,,, ( 6b), 6b M = P (L + a) /2 M = P (L + a) /2 ( a =, 7b 100mm),, 213,,,,,,,, ;, 7c,, ;, 3. 2,,,,,, y ;,, y 1 y 2 y 3 y 4 y,,,, ; 1, N / ( f c A c + f yr A r + f ys A s ) f c, 1 f cu [11 ] ; f ys f yr 2 34 3,,,,,, 8a,,,,,

7 Fig. 7 Phenomena of specimen in first phase test,,,, 8b 8c,,,, 8 Fig. 8 Phenomena of specimen in second phase test 4 411 2 9 10, P 0 : P 0 = 4M 0 /L; P 0 = 2M 0 / L + a ; M 0 N P 2M P ( ) N = 0 M, /L ( ) / (L + a) ( ) 9 2, Fig. 9 Hysteretic loop s of specimens in first phase test : (1) 2,, ( ), ( ) ( 217),, (2) 0102,,,, 35

10 Fig. 10 Hysteretic loop s of specimens in second phase test (3),,,, 11 ( [ 3 ] specimen 4, 0129, 416%, 418; [ 12 ] S122521, 0125, 417%, 110) N / ( f c A ), N ; f c ; A (213 ) [ 3 ] specimen 4 n = 0117 ( [ 12 ], ) :, 0117,, 30%, 01567, 36

13 Fig. 13 Strain gauges location 11 Fig. 11 Hysteretic loop s of comparative specimens 412 2 12 SRCF 21 323 ( 3a, 50mm) SRCP 21 424 ( 3b, 50mm ) P ; P,, 13 4, 12, 20000 10 26 ( SRCF 21 S34, SRCP 21 S19),,, 413 (1) = u / y ( 1), y ; u y u, R1Park [ 10 ] y, 14 ( SRCF 21 ),, 15% 3, 1 /20; 3 12 2 Fig. 12 Load2strain curves 37

M p = P l 4 + N ( ) ( 3), l, 214m; 114m; P ; N ; 14 R1Park y Fig. 14 Definition of ductility ratio 3 ( /L, / (L + a) ) Ta b le 3 D uc tility and defo rm a tio n y /mm u /mm SRCF 21 1615 1 /73 7616 1 /16 416 SRCF 21 1516 1 /77 5516 1 /22 315 SRCP 21 518 1 /121 3117 1 /22 515 SRCP 22 612 1 /113 3816 1 /18 612 SRCP 21 419 1 /143 2615 1 /26 514 SRCP 22 418 1 /146 3518 1 /20 715 SRCP 21 514 1 /130 3610 1 /19 617 SRCP 22 517 1 /123 4013 1 /17 711 SRCP 21 416 1 /152 3211 1 /22 710 5 N P M P 15 N P 2M P, N P M P [ 13 ] : (1) ; (2), ; (3) N P 2M P, 2, ( 1), ; 4 M p, M p = P l 8 + N ( ) ( 2) 2 15 N P 2M P Fig. 15 N P 2M P interaction diagram s and test results 15 4, N P 2M P,,, : (1),, ; (2),, 6 CCTV SRC, : (1),, ( ) 4 Tab le 4 M a in te st re su lts SRCF 21 SRCF 21 SRCP 21 SRCP 22 SRCP 21 SRCP 22 SRCP 21 SRCP 22 SRCP 21 N / kn 1910 3200 3210 3210 2730 2730 2250 2250 1760 M p /kn m 60410 58810 58015 60016 52219 56515 51214 58713 54915 38

,, 1 /26, SRC (2) SRC N P 2M P, N P 2M P, N P 2M P (3) [ 1 ] JGJ 138 2001 [ S ]. ( JGJ 138 2001 Technical specification for steel reinforced concrete composite structures [ S ]. ( in Chinese) ) [ 2 ] YB 9082 97 [ S ]. ( YB 9082 97 Specification for design of steel2reinforced concrete structure[ S]. ( in Chinese) ) [ 3 ] R icles J M, Paboojian S D. Seism ic performance of steel2 encased composite columns [ J ]. Journal of Structural Engineering, 1994, 120 ( 8) : 247422494. [ 4 ] El2Tawil S, Deierlein G G. Strength and ductility of concrete encased composite columns [ J ]. Journal of Structural Engineering, 1999, 125 ( 9) : 100921019. [ 5 ] M irza S A, Lacroix E A. Comparative strength analyses of concrete2encased steel composite columns [ J ]. Journal of Structural Engineering, 2004, 130 ( 12) : 194121953. [ 6 ] W ang, Y C. Tests on slender composite columns [ J ]. Journal of Constructional Steel Research, 1999, 49 ( 1) : 252 41. [ 7 ] Chen C C, L i J M, W eng C C. Experimental behaviour and strength of concrete2encased composite beam2columns with T2shaped steel section under cyclic loading[ J ]. Journal of Constructional Steel Research, 2005, 61 ( 7) : 8632881. [ 8 ]. [M ]. :, 2001. ( Zhao Hong2tie. Composite structure of steel and concrete [ M ]. Beijing: Science Press, 2001. ( in Chinese) ) [ 9 ],,. [ J ].. 1999, 29 ( 7 ) : 14216. ( Chen Zong2 liang, Zhang Yu, L i Xiang2m in. Reasonable steel content for steel reinforced high strength concrete columns[ J ]. Building Structure. 1999, 29 ( 7) : 14216. ( in Chinese) ) [ 10 ],. [M ]. :, 2006. (J ia J in2qing, Zhao Guo2 fan. Mechanics performance of steel reinforced high2strength concrete short columns [ M ]. Dalian: Dalian University of Technology Press, 2006. ( in Chinese) ) [ 11 ] GB 50010 2002 [ S ]. ( GB 50010 2002 Code for design of concrete structures[ S ]. ( in Chinese) ) [ 12 ]. [M ]. :, 1994. ( Research Team for Mechanical Performance of Stub Columns. Mechanical performance and calculation method of steel reinforced concrete stub columns[m ]. Beijing: China A rchitecture and Building Press, 1994. ( in Chinese) ) [ 13 ],. [M ]. :, 1985. (W ang Chuan2zhi, Teng Zhi2 m ing. The theory of reinforced concrete structure [ M ]. Beijing: China A rchitecture and Building Press, 1985. ( in Chinese) ) 39