Experimental Study On Seismic Performance Of Replaceable Concrete Coupling Beam Considering Influence Of Floor Slab

The ordinary reinforced concrete beam is prone to brittle shear failure under earthquake,the energy consumption capacity of coupling beams are greatly reduced,and even causes the destruction of the wall limbs.As a new energy dissipation component,replaceable concrete coupling beam can not only greatly increase the energy dissipation capacity,but also greatly improve the post-earthquake recoverability of coupled shear wall structure system.Based on the interaction between the floor slab and the replaceable concrete coupling beam,this paper discusses the seismic behavior of the coupling concrete beam with replaceable energy dissipation steel beam section considering the influence of the floor slab,and focuses on the damage of the floor slab.In this paper,four replaceable concrete beams with different types of RC floor slabs are designed.The first is to replace the concrete in the middle of the floor slab with ECC material,and to reserve deformation joints at the connecting position of nonreplaceable segment and replaceable segment(RCBECC).The second is a noconnection treatment between the floor and the beam to reduce the connection between them(RCBUP).The third is to splice the two floors through prestressed steel strand to form a whole floor slab(RCBPF).The last one is used as a control specimen,whose floor is not treated(RCBCT).This paper completed the pseudo-static test and nonlinear finite element analysis of four replaceable concrete coupling beams with RC floor slabs.The main research contents are as follows:(1)The pseudo-static tests of four replaceable concrete beam specimens with floor slabs were designed and manufacture.The bearing capacity,deformation capacity,hysteretic curve,crack distribution and failure mode of floor slab and beam were obtained.The results show that RCBECC and RCBUP have a relatively low degree of floor damage,RCBECC has the smallest floor crack width and RCBUP has the lowest number of floor cracks.The hysteretic curves of RCBUP and RCBPF are very full,with relatively good displacement ductility and energy consumption.(2)Four finite element models of replaceable concrete coupling beam with floor are established using ABAQUS.The correctness of the four models was verified by comparing with the test results,indicating that the modeling method and model parameters adopted in this paper are reasonable and effective.(3)Based on the finite element model,a further parameter analysis was carried out to discuss the influence of the different parameters on the seismic performance and the damage of the floor slab of the replaceable concrete coupling beam considering the influence of floor slab.The results show that the initial stiffness of the replaceable concrete coupling beams is greatly affected by the RC floor slab,while the bearing capacity is less affected.The influence of the stiffness ratio of the non-replaceable section to the replaceable section on the initial stiffness and bearing capacity is far less than that of the strength ratio.Changing the floating distance of the floor has no great influence on the initial stiffness of the whole specimen,and the effect is better when the floating distance of the floor is about 15 mm.Changing the section area of prestressed reinforcement and the size of initial prestress of the floor has no significant effect on the load-displacement curve of specimens;the damage to the floor slab decreases slightly,however,with the increase of the initial prestress.