高温后型钢混凝土柱抗震性能试验研究

为评估火灾后型钢混凝土柱的抗震能力，为其火灾后加固提供参考，进行了11个型钢混凝土柱试件的高温后抗震性能试验。试件在升降温过程中施加恒定轴向荷载，并且在高温后抗震试验中保持相同的轴向荷载水平。试验中考虑轴压比和受火时间对抗震性能的影响，以获取并分析试件的破坏特征、荷载-位移滞回曲线、刚度、延性和耗能能力。试验结果表明：型钢混凝土柱试件在反复荷载作用下由柱底混凝土剥落形成塑性铰，塑性铰长度为0.14H~0.44H(H为柱截面高度)；试件在反复荷载作用下出现贯通全柱的黏结滑移裂缝，滞回曲线大致呈梭形，耗能能力较好；较之未受火试件，受火后试件滞回曲线更为饱满，骨架曲线更为平缓，位移延性系数略有增大，刚度和承载力退化明显，耗能能力略有降低。受火时间相同时，轴压比大的试件极限荷载略高，极限位移较小，延性差，耗能能力更强；轴压比相同时，受火时间越长，承载力和刚度下降越明显，延性略有提高，耗能能力变差。

Experimental research on seismic performance of steel reinforced concrete columns after exposure to fire

To investigate the seismic performance of steel reinforced concrete (SRC) columns after exposure to fire, which is the reference for the evaluation and strengthening of this kind of columns under earthquake, eleven SRC columns were used, based on cyclic reversed loading tests. Constant vertical load was applied on the columns during the fire test including heating and cooling phases, and the loads were resumed to the lever in the fire during the cyclic reversed loading tests. Influences of axial compression ratio and heating time on the post-fire performance of the SRC columns were considered in the test. The failure mode, hysteretic loops, skeleton curves, stiffness degradation, ductility and energy dissipation of specimens were obtained and analyzed through the test data. The test results show that a plastic hinge with a length of 0.14~0.44 times of the height of the column cross section appears at the bottom of all specimens under cyclic loading, and obvious slippage cracks through the height of column between steel and concrete occurs. The hysteretic loop is a spindle shape. The energy dissipation ability is good after fire. Compared with the ambient specimens, the SRC columns after exposure to fire have fuller loops, more flat skeleton curves and higher ductility coefficient. The stiffness and load bearing capacity of the SRC columns decrease obviously after exposure to fire. The energy dissipation ability of the specimens decreases a little. When the heating time is the same, the load bearing capacity and energy dissipation increase with increasing of the axial load ratio, while lower the critical lateral displacement and ductility decreases. When the axial load ratio is the same, with the increasing of the heating time, the stiffness, energy dissipation ability and the load bearing capacity decrease, while the ductility increases a little.