Study On Seismic Performance Of Double Steel Plates And Concrete Infill Composite Shear Wall For Nuclear Structural Engineering

Double steel plates and concrete infill composite shear walls(SCSW)is a composite structure which consists of the steel faceplates and the plain concrete infill.It is a new kind of component to resist lateral force.SCSW is applied in the shielding workshop of CAP1400 nuclear structural engineering due to its good mechanical properties,the ability of shock resistance and the advantages in construction convenience.The seismic safety performance of SCSW is a key problem in nuclear structural engineering which must be solved in the design and application of the CAP1400.However,research on SCSW structure in China is not very comprehensive and the corresponding design specification is lacked.Based on the program of CAP1400 nuclear structural engineering,the seismic performance such as mechanical characteristics,damage characteristics,hysteresis curve,lateral stiffness and the buckling of the steel plates of the shear wall specimens under in-plane and out-of-plane loading are studied in this paper by specimen test.The numerical models of test specimens are established by using the finite element software ABAQUS.The validity of the numerical models are verified.The main works and research results are summarized as follows:(1)9 SCSW specimens and 1 reinforced concrete specimen are designed and conducted.The mechanical performance and failure mechanism of SCSW specimens under in-plane loading are studied through experiment.The influence of several parameters consist of stud space,the thickness of the steel plate,the vertical load,and stiffener on in-plane seismic performance of SCSW are analyzed,and the hysteresis curve,the stiffness degradation,and the energy dissipation capacity of SCSW specimens are studied.The research shows that the SCSW specimens have better ductility and seismic performance than reinforced concrete shear walls.The changes of the stud space have little influence on the lateral stiffness and the bearing capacity of SCSW specimens,the energy dissipation capacity of SCSW specimens is improved greatly with the increase of the thickness of the steel plates,the bearing capacity of the shear wall specimens is improved when the vertical load increases within a certain range,the lateral stiffness and the bearing capacity of the shear wall specimens is improved when the stiffeners are set.On the basis of the experimental study,the simplification and calculation assumes are made to the shear wall specimens,and the calculation formula of the bearing capacity of SCSW under in-plane horizontal cyclic loading is given.(2)5 SCSW specimens and 1 reinforced concrete specimen are designed and the out-of-plane cyclic loading test on the specimens are conducted.The mechanical performance,failure mechanism,the lateral stiffness and the energy dissipation capacity of SCSW specimens under out-of-plane loading are studied through experiment.The influence of the thickness of the steel plate,the vertical load,and the strength of concrete on out-of-plane seismic performance of SCSW are analyzed.The results show that the ultimate bearing capacity of SCSW is improved obviously with the increase of vertical load,the lateral stiffness of SCSW specimens have no apparent influence when the strength of concrete changes within a certain range,the lateral stiffness and the ultimate bearing capacity of SCSW specimens increase with the increase of the thickness of the steel plate.The calculation formula of the cracking load and the flexural bearing capacity are presented on the basis of experimental results and theoretical analysis.(3)The numerical model of SCSW specimens under in-plane and out-of-plane loading are established respectively by using finite element software ABAQUS.The steel plates and the concrete are simulated with solid elements and the connection behavior of the stud is simulated by spring elements.The coulomb friction and hard contact are used to simulate the contact respectively on the tangential and normal direction considering the interaction between the steel plates and the concrete.The mechanical characteristics,failure mode and the ultimate bearing capacity of the specimens under in-plane and out-of-plane cyclic loading are studied by numerical analysis.It is found that the results between numerical simulation and the experiment is consistent and the differences between them are analyzed.(4)The buckling behavior of the steel plates of SCSW under in-plane and out-of-plane loading are studied respectively through test and numerical analysis.The research shows that the buckling position of the steel plates is located at the base of the shear wall and the buckling strain of the steel plate is less than the yield strain of the steel plate.The horizontal load when the buckling occurs is analyzed by using yielding point method.It can be seen that the load when the buckling of the steel plate occurs is less than the ultimate load of the specimen.By comparing the buckling load-strain curve of the test and the finite element analysis of the steel plate,it is found that both the position of the turning points is consistent.It shows that the results of the finite element analysis can reflect the buckling stress of the steel plate.