集中配筋连接预制剪力墙抗震性能试验研究

Experimental investigation on seismic behavior of precast shear walls with centralized reinforcement connection

针对现有预制混凝土剪力墙接缝施工容错率低、混凝土现场浇筑作业量大和钢筋锚固过长等不足,提出一种使用超高性能混凝土(UHPC)的集中配筋连接预制剪力墙。通过对比1片现浇剪力墙试件、3片不同接缝形式的集中配筋连接预制剪力墙试件的拟静力试验结果,揭示该类预制剪力墙的破坏规律和抗震性能、竖缝对墙体抗震性能的影响和连接钢筋的受力特点。采用ABAQUS软件对试件进行有限元模拟,分析轴压比和集中配筋率对试件抗震性能的影响。研究结果表明:预制试件与现浇试件具有相同的破坏规律,均为弯剪破坏;这2类试件的滞回曲线均较饱满,骨架曲线走势基本一致,耗能能力接近,且预制试件的最小承载力仅比现浇试件低5.6%,表明预制试件的抗震性能与现浇试件的抗震性能基本相同;竖缝对剪力墙承载力的影响较小,使剪力墙的延性和耗能能力有一定的削弱;不同竖缝形式预制墙的抗震性能相近但各有特点,竖缝形式预制墙采用UHPC出筋搭接具有更好的整体性,采用U形键槽的预制墙具有更大的刚度和更强的耗能能力;连接钢筋的应力分布具有典型受弯构件的特征;随着轴压比增加,模型的刚度和承载力不断增加,在轴压比从0.05增加到0.30时,最大的峰值荷载增幅发生在轴压比从0.05到0.10时,从承载力的提高、刚度、耗能和墙角抬高等方面考虑,试件的集中配筋率保持在90%~110%为宜。

In view of the shortcomings of the existing precast concrete shear wall joint construction,such as low fault tolerance rate,large amount of concrete pouring operations on the construction site and excessively long reinforcement anchorage,a centralized reinforcement connection precast shear wall structure with ultra-high performance concrete(UHPC)was proposed.By comparing the quasi-static test results of one cast-in-place shear wall specimen and three centralized reinforcement connection prefabricated specimens with different joint forms,the failure law and seismic performance of this kind of prefabricated shear wall were revealed,and the effect of vertical joints on the seismic behavior of the wall and the stress characteristics of the connecting steel bars were clarified.In addition,ABAQUS software was used to conduct finite element simulation of the specimen,and the influence of axial compression ratio and concentrated reinforcement ratio on the seismic performance of the specimen was analyzed.The results show that the centralized reinforcement specimen and the cast-in-place specimen have the same failure law,and both are bending shear failure.The hysteresis curves of the two types of specimens are relatively full,the skeleton curve trend is basically the same,and the energy consumption capacity is close.The minimum bearing capacity of the centralized reinforced specimen is only 5.6%lower than that of the cast-in-place specimen,indicating that the seismic performance of prefabricated specimens is basically equal to that of cast-in-place specimens.Vertical joints have little influence on the bearing capacity of the wall,and weaken the ductility and energy dissipation capacity of the wall to some extent.The seismic performance of precast walls with different vertical joints is similar but different,the precast wall with UHPC rib-out lap in vertical joint form has better integrity,and the precast wall with U-shaped keyway has better stiffness and energy dissipation capacity.The stress distribution of the connected steel bar has the characteristics of typical flexural members.The stiffness and bearing capacity of the model increase with the increase of axial compression ratio,when the axial pressure ratio increase from 0.05 to 0.30,the largest peak load increase occurs when the axial pressure ratio increases from 0.05 to 0.10.Considering the improvement of bearing capacity,stiffness,energy dissipation and corner elevation,it is advisable to keep the concentrated reinforcement ratio of specimens at 90%-110%.