预制-后浇型混凝土双面叠合连梁受剪性能研究

Study on Shear Performance of Precast-postcast Concrete Double-faced Superposed Coupling Beams

为更好满足建筑工业化要求,基于叠合剪力墙结构体系提出一种预制-后浇型混凝土双面叠合连梁,该叠合连梁可与叠合墙肢在工厂整体预制,为提高生产效率,采用钢筋桁架替代箍筋作为抗剪钢筋。对5根连梁进行受剪性能试验,包括3根新型双面叠合连梁(剪跨比λ分别为1.2,1.5,1.8)、1根叠合连梁以及1根现浇对比连梁。结果表明,所有连梁均发生剪压破坏。双面叠合连梁的受剪承载力、位移延性系数分别为现浇连梁的81.3%、92.3%,同时观察到极限破坏时叠合面未出现相对滑移,钢筋桁架的上、下弦筋均发生屈服。随着剪跨比增大,双面叠合连梁受剪承载力降低但变形能力提高。基于ABAQUS有限元软件建立了精细化数值模型,计算结果与试验结果拟合良好。参数分析表明,双面叠合连梁预制板完全由箍筋连接时较完全由钢筋桁架连接时,受剪承载力提高了10.0%,极限挠度提高了27.3%,增大预制-后浇混凝土叠合面摩擦系数可有效提高新型连梁的受剪承载力。

For better meeting the requirements of building industrialization,a novel precast-postcast concrete double-faced superposed coupling beam(DFSCB)was proposed based on the superposed shear wall structure system,which could be prefabricated with the superposed walls in the factory.For improving the assembly efficiency,steel bar truss was used to replace the stirrups as the shear reinforcement compared to the conventional cast-in-place coupling beams.Shear tests were conducted on three DFSCBs(>=1.2,1.5,and 1.8),one superposed coupling beam,and one cast-in-place comparison coupling beam.The results show that all specimens failed in shear-compression failure mode.The shear strength and dis-placement ductility coefficient of DFSCB are 81.3%and 92.3%of cast-in-place coupling beam,while it was observed that no relative slip on the superposed surfaces and both the upper and lower chords of steel bar truss yielded during ultimate damage.A decrease in shear strength but an increase in deformation capacity of DFSCBs could be obtained,as their shear-span ratio increased.A high-fidelity numerical model,validated against experimental results,was developed using ABAQUS finite element software.Parameter analysis shows that when the prefabricated panels of the DFSCBs were con-nected by stirrups entirely,as opposed to steel bar truss,the shear strength increased by 10.0%and the ultimate deflec-tion by 27.3%.Increasing the friction coefficient of the precast-postcast concrete superposed surface could effectively im-prove the shear strength of the DFSCBs.