L形钢管混凝土柱抗震性能非线性有限元分析

为深入了解低周反复荷载下L形钢管混凝土柱的抗震性能,以试验研究为基础,依据L形钢管混凝土柱核心混凝土在低周反复荷载作用下的应力-应变关系,采用有限元程序Opensees,对L形钢管混凝土柱的抗震性能进行非线性分析,给出其荷载-水平位移关系曲线;并分析L形钢管混凝土柱抗震性能的影响因素。结果表明:计算结果与试验结果吻合较好;截面宽厚比D/t和截面长宽比D/B对构件骨架曲线的影响相似,总体上对荷载-位移骨架曲线的形状影响很小,主要表现在对水平承载力大小的影响;轴压比是构件骨架曲线的主要影响因素,轴压比对试件弹性阶段的刚度影响不大,对构件弹塑性阶段刚度影响明显,随着轴压比的增大,试件的刚度也逐渐变小,水平极限承载力变小,并且曲线将会出现下降段,且下降段的下降幅度随轴压比的增加而增大,表明构件的位移延性也越来越差。

NONLINEAR FEM ANALYSIS OF SEISMIC BEHAVIOR OF L-SHAPED CONCRETE-FILLED STEEL TUBULAR COLUMN

To study the seismic behavior of L-shaped concrete-filled steel tubular column,based on experimental study and stress strain relationship of the core concrete of L-shaped concrete-filled steel tubular column subjected to low cyclic loading,nonlinear finite element method analysis of L-shaped concrete-filled steel tubular column is carried out by Opensees software. The lateral load (P) versus lateral displacement envelope curves and its influencing factors are analyzed. The results show that the calculation results totally correspond with experimental results. The influence of the width-thickness ratio D /t on the envelope curve is similar to that of the length-width ratio D /B,which has little effect on the shape of the envelope curve but will influence the lateral loading capacity. The axial compression ratio is the main factor affecting the envelope curve of the member. In the elastic stage,the influence of the axial compression ratio on the stiffness of the member is small while it is significant in elastic-plastic stage. As the increase of the axial compression ratio,the stiffness of the member and the horizontal loading capacity will decrease. Meanwhile,the curve becomes descendent and the descent amplitude will increase as the increase of the axial compression ratio,which indicates that the ductility of the member becomes worse.