Experimental Study On Quasi-Static Force Of Precate Shear Wall Connected With Keyway And Concentrated Reinforcement

At present,the assembly rate of prefabricated buildings in China is low,and there are some problems such as low degree of industrial construction and complex structural connection.The research group proposed a new system of assembling shear wall structure connected with keyway and centralized reinforcement,which combined keyway with centralized reinforcement and UHPC irrigation hole,greatly reducing the construction accuracy requirement and improving the structural integrity.In order to master the mechanical properties of the prefabricated shear wall structure system connected with keyway and concentrated reinforcement,the direct shear test and pseudo-static test of the prefabricated shear wall connected with keyway and concentrated reinforcement were carried out in this thesis,and the finite element analysis and calculation method of the new connected shear wall were established.The specific work is as follows:(1)Direct shear tests of joints connecting five keyways with concentrated reinforcement were carried out to study the effects of different coaxial pressure ratio,connection degree and pass type parameters on the shear properties of joints.The results show that the joints with 109% connection degree have good shear properties,the shear stiffness of joints is large,oblique cracks are not fully developed,and there is no horizontal keyway penetration failure.UHPC hole reinforcement lap connection can effectively transfer stress.It is recommended that the joints should be properly joined with 67%～100%joint degree.The axial compression ratio and joint degree affect the shear capacity of joints.The increase of 0.1 axial compression ratio and 20%joint degree increases the shear capacity of joints by 45.9% and 5%,respectively.The pass type does not affect the shear capacity of joints.(2)Pseudo-static tests were carried out on the prefabricated shear wall connected with three keyways and centralized reinforcement and one cast-in-place shear wall to study the seismic performance of the prefabricated shear wall connected with this form and the effect of vertical joints on the seismic performance of the wall.The results show that: The development degree of inclined cracks in prefabricated shear wall is lower than that in cast-in-place shear wall.The reserved hole wall in the middle is prone to cross inclined cracks,and the keyway slurry layer is broken through.However,the stiffness of prefabricated shear wall is higher than that of cast-in-place shear wall,the bearing capacity is slightly lower than that of cast-in-place shear wall by about 5%,and the ductility energy consumption index is slightly lower than that of cast-in-place shear wall.It can be seen that the mechanical properties of prefabricated shear wall with concentrated reinforcement are basically equal to those of cast-in-place wall structure.The vertical joints have little effect on the bearing capacity and reinforcement strain of the wall,but can slightly improve the lateral stiffness of the wall and the slip degree of the horizontal keyway,which verifies the reliability of UHPC lap connection and pure keyway grouting vertical joints.(3)Based on the test,the finite element analysis model of the assembled shear wall with keyway and centralized reinforcement was established and verified,and the parameters of axial compression ratio and vertical steel connection degree were analyzed.The influence is significant,and has little effect on the initial stiffness of the wall.The influence law of the axial compression ratio and connection strength on the bearing capacity is analyzed and obtained;the bearing capacity of the assembled shear wall connected with the keyway and the centralized reinforcement considering the axial compression ratio and connection strength parameters is proposed.The simplified model of force calculation is used,and the calculated results are in good agreement with the experimental results.