Study On The Mechanical Performance Of The Floor Joints Of The Superposed Shear Wall Under The Action Of Out-of-Plane Load

The superposed shear wall is a semi-assembled building structure system introduced from Germany and suitable for the industrialization of my country’s construction.The superposed wall panel of the main load-bearing member consists of two prefabricated reinforced concrete panels connected by truss steel bars on the outside and The wall is composed of cast-in-place concrete in the middle cavity,and the wall is connected by inserting horizontal and vertical steel bars into the post-cast cavity.The superposed shear wall structure is not only light weight,energy saving and energy saving,but also has strong structural integrity due to the presence of cast-in-place concrete.It is a structural system widely used in multi-story and high-rise buildings.In order to study the mechanical performance of the superposed shear wall floor node under the action of out-of-plane load,the out-of-plane mechanical performance test and finite element analysis of the superposed shear wall floor node are carried out.The main research work and achievements are as follows:(1)Design and manufacture superposed shear wall floor joint specimens and cast-in-place shear wall floor joint specimens,and conduct out-of-plane monotonic pseudo-static load tests.The failure mode,load-displacement curve,The comparison of behavior parameters such as stiffness,bearing capacity and ductility,analyzes the difference in the mechanical behavior of the superposed shear wall floor joints and the cast-in-situ shear wall floor joints.(2)The test results show that under the action of out-of-plane load,the crack distribution and failure form of the floor node of the superposed shear wall and the floor node of the cast-in-situ shear wall are basically the same,and both have bending failure;the wall body of the floor node of the superposed shear wall The cracking load and initial stiffness are respectively 11.11% and 13% higher than those of the cast-in-situ shear wall floor nodes;the peak bearing capacity and ductility coefficient are respectively 15.58% and 9.42% lower than those of the cast-in-situ shear wall floor nodes.(3)The finite element software Abaqus is used to simulate the shear wall floor node specimens,and the accuracy of the finite element modeling method is verified by the test results.On this basis,the parametric analysis is carried out,and the axial compression ratio,the vertical connection reinforcement spacing,the longitudinal reinforcement anchorage mode of the floor and the concrete strength are studied as parameters,The influence of these parameters on the peak bearing capacity and ductility of the superposed shear wall floor nodes is analyzed.The results of finite element analysis show that when the axial compression ratio increases from 0.1 to0.2,the bearing capacity increases by 6.71% and the ductility coefficient decreases by12.6%;When the axial compression ratio increases from 0.2 to 0.3,the peak bearing capacity increases by 11.46% and the ductility coefficient decreases by 19.92%.The results show that the bearing capacity of floor joints can be improved by less than 10%by reducing the spacing of vertical connecting bars;The strength of concrete is increased by one grade,and the peak bearing capacity of specimens is increased by about 4% ～ 5%.Finally,on the basis of the existing experimental research results,the key issues that still need to be studied in depth on the floor nodes are put forward.Figure [40] table [11] reference [61]...