Study on seismic behavior of complex cross-section multi-cell CFST bifurcated-columns
QIAO Qiyun;LI Xiangyu;CAO Wanlin;WU Haipeng;YIN Fei;College of Architecture and Civil Engineering,Beijing University of Technology;
In order to study seismic behavior of the complex cross-section concrete filled steel tube( CFST) bifurcated-columns under horizontal forces in different directions,based on a super high-rise building with multi-cell CFST mega bifurcated column,four 1 /30 scale bifurcated-column specimens were designed and tested under two kinds of low cyclic load in different directions. One was along the long axis and another was along the short axis.The cross-section constructional details were divided into two types,one thickness of the cell steel plate was 2 mm and another was 3 mm. The failure modes,hysteresis behavior,bearing-capacity,ductility,stiffness degradation,and energy dissipation were analyzed. Research shows that the mechanical property of complex cross-section CFST bifurcated-columns varies evidently in different directions,and the seismic behavior of the bifurcated-columns can be strengthened by a reasonable increase in the thickness of the steel plate.