SCFT柱-H型钢梁平面框架抗震性能分析

Seismic Behavior of SCFT Column-H Section Steel Beam Plane Frame

针对SCFT柱-H型钢梁平面框架,采用ANSYS建立非线性模型,进行了7组框架模型在低周反复荷载作用下的受力特性分析,研究了轴压比和有无填充墙对SCFT柱框架力学性能的影响规律.分析发现:7组框架模型滞回曲线饱满,骨架曲线下降段平缓;在受压单肢钢管受压区达到屈服强度时,SCFT柱仍可视为整体受力构件并继续承担更大荷载,有效延缓整体框架的塑性变形,因此,SCFT柱框架具有良好的抗震性能;轴压比对SCFT柱框架的刚度退化影响并不明显,随轴压比增加,框架的极限承载力和延性有所降低,达到极限承载力后的强度退化明显;填充墙在SCFT柱框架加载前期能够有效分担水平荷载,显著提高框架承载力和弹性刚度,但刚性连接会加剧墙体过早压碎破坏,建议工程中采取柔性连接或预留缝隙,以减小填充墙震害,并改善墙体与SCFT柱框架的协同工作性能.

In this paper, SCFT column-H section steel beam plane frame is analyzed through establishing nonlinear finite element models by ANSYS. Seven sets of models were built under low cyclic loading conditions. The mechani- cal characteristics of these frame models were simulated. The axial compression ratio was set to be the control variable, and the influence of infilled wall on the frame was studied as well. The result shows that all the seven sets of models present symmetrical and smooth plumped hysteretic curves under low cyclic loadings, and the decending segment of the skeleton curve is slightly inclined; after mono-steel tube column reaches its yield strength in the com- pression section, the entire SCFT can still take more load as an integrated member, and therefore it delays the plastic deformation of the frame, showing its preferred earthquake resistant capacity; no promising evidence shows that the axial compression ratio has a strong influence on the frame＇s stiffness degradation, however, as the ratio increases, the ultimate beating-capacity and displacement ductility both decrease, and the strength decreases obviously after it has reached ultimate bearing-capacity; the infilled wall bears a considerable amount of lateral load at the early stage of loading, increasing the bearing-capacity and elastic stiffness of the plane frame obviously. Considering that the rigid connection to infilled wall results in early crash of the wall, it is suggested that flexible connections or extension joints between the frame and infilled wall should be adopted in practical constructions to reduce the damage.