六层两跨现浇柱预制梁框架抗震性能试验研究

以六层现浇柱叠合梁框架实际工程为原型,通过一榀1∶4比例的六层两跨现浇柱预制梁框架的低周反复荷载试验,对其受力过程、破坏形态、破坏机制、位移延性、滞回曲线、骨架曲线、刚度退化、耗能能力以及等效黏滞阻尼系数等进行了较系统的研究。结果表明:现浇柱预制梁框架在低周反复荷载下实现了强柱弱梁、强节点弱构件的设计目标;破坏机制为混合机制,即塑性铰首先在梁端出现,在二层梁端出现塑性铰后柱端才开始出现塑性铰,试件以二层柱脚混凝土部分压碎剥落、柱内纵筋压曲外露为破坏标志,节点核心区内的箍筋在整个试验过程中处于弹性状态;框架整体及层间的滞回曲线表现出一定的捏拢现象;框架正、反向整体位移延性系数分别为3.9和5.3,表明其在低周反复荷载下具有较好的位移延性。研究成果可为预制混凝土框架在地震区的推广应用提供技术依据和基础数据。

Experimental study on seismic behavior of six-story two-bay frame with precast beams and cast-in-place columns

This paper reports an experimental study on seismic behavior of a six-story two-bay frame with precast beam and cast-in-place column,which is from a six story prototype residential building.Based on the cyclic loading test,seismic behavior of the test specimen was evaluated in terms of failure modes,failure mechanism,stiffness degradation,deformation restoring capacity,energy dissipation capacity,displacement ductility etc.The test results showed that the tested frame achieved the design objective of strong column-weak beam and strong joint/weak element.The failure mechanism was a mixed side sway mechanism,with the first plastic hinge occurred at the beam end,and the plastic hinge began to appear at the column end while there were some plastic hinges in beam end.The test was stoped due to concrete crushing and buckling of longitudinal bars as a result of plastic hinges at the two-story column end,and the strains of the ties in the joints remained in elastic stage;the hysteretic curves of the test specimen were not full;the overall displacement ductility in positive and negative directions was 3.9 and 5.3,respectively,showing good ductility.The achievements in this study could be instructive for the application of precast concrete structures in seismic zones.