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(λ=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.
concrete double-faced superposed coupling beamssteel bar trussshear performanceshear-span rationumerical simulation
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