Experimental Research On Seismic Behavior And Calculation Method Of Monolithic Precast Fiber Recycled Concrete Shear Wall

In order to solve the problems existing in the precast shear wall structure,such as single use of wall materials,complex and poor reliability of the connections,poor overall performance of the structure,the lack of multi-channel seismic defense systems and other problems,the structural principle of ecological composite wall and precast shear wall structure are combined organically,and the advantages of each other are complemented.In this paper,monolithic precast fiber recycled concrete shear wall structure is proposed.It is assembly composed by precast green concrete panel,cast-in-situ edge connecting components(including vertical edge component,connecting column and constraint concealed beam)and cast-in-situ floor or composite floor.The application of precast green concrete panel and composite floor can not only improve the precast ratio of monolithic precast fiber recycled concrete shear wall,but also effectively solve the problem of less use of new wall materials.With the development of industrialization of housing industry,monolithic precast fiber recycled concrete shear wall structure will have broad application prospects.Taking the monolithic precast fiber recycled concrete shear wall as the research object,the seismic performance of monolithic precast fiber recycled concrete shear wall under low-cyclic reveresd loading was systematically studied and the corresponding design and calculation theory was established by means of experimental research,numerical simulation and theoretical analysis.The following researches in this paper were carried out:(1)19 specimens of monolithic precast fiber recycled concrete shear wall were produced in this paper.The design parameters mainly include vertical reinforcement splicing in precast panel,vertical joints connection form in precast panel,reinforcement pattern of precast panel,materials of precast panel,axial compression ratio.the failure processes,modes and mechanisms of monolithic precast fiber recycled concrete shear wall under low-cyclic reveresd loading were mastered.The hysteresis and skeleton curves of the specimens were analyzed,and the effects of the design parameters on the bearing capacity,ductile deformation characteristics,strength degradation,stiffness degradation,energy dissipation capacity and steel strain analysis were obtained.The seismic influence law of monolithic precast fiber recycled concrete shear wall were summarized in this paper.(2)Combined with the experimental results,the hysteretic simulation analysis of the monolithic precast fiber recycled concrete shear wall was carried out by using ABAQUS finite element software.The simulation results and test results were compared,which verified the accuracy of the model.On this basis,the parameters such as longitudinal reinforcement ratio,diameter of reinforcement,height-width ratio,axial compression ratio,number and location of pre-embedded welded plates were analyzed,and the law of the influence of the corresponding parameters on the seismic performance of the monolithic precast fiber recycled concrete shear wall was given.(3)Based on the test results,the effects of the key parameters such as vertical reinforcement splicing in precast panel,vertical joints connection form in precast panel,reinforcement pattern of precast panel,materials of precast panel,axial compression ratio on the axial force-moment capacity,shear capacity of oblique section and shear capacity of horizontal joints of monolithic precast fiber recycled concrete shear wall were analyzed.The stress state of the wall at different stages was analyzed in detail,and the axial force-moment capacity of the monolithic precast fiber recycled concrete shear wall is calculated theoretically.The difference between the calculation of the axial force-moment capacity of the monolithic precast fiber recycled concrete shear wall and cast-in-situ shear wall was fully considered.Based on the softened strut-and-tie model,a formula for calculating the shear capacity of oblique section of the monolithic precast grid shear wal was proposed.Considering the influence of precast panel distribution reinforcement connection mode on the shear capacity of horizontal joints,a formula for calculating shear capacity of horizontal joints based on different reinforcement connection modes was proposed.The accuracy of the proposed formula was verified by comparing the proposed formula with the experimental results or the results of finite element calculation.(4)Based on the experimental results,the hysteretic behavior and restoring force characteristics of the wall were deeply analyzed.A four-line restoring force model suitable for monolithic precast fiber recycled concrete shear wall was proposed by combining theoretical calculation with regression of experimental data.The model included calculating skeleton curve,unloading stiffness at different stages and calculating hysteresis curve.The accuracy of the restoring force model was verified by comparing the calculated restoring force model with the experimental results.(5)According to the characteristics of deformation and hysteretic energy dissipation of the monolithic precast fiber recycled concrete shear wall,a nonlinear composite seismic damage model with two parameters of deformation and energy dissipation was proposed.Evolution analysis of damage index at different stages of the structure was carried out by using the established seismic damage model.The influence of design parameters on the damage performance of the specimens was discussed.The corresponding damage state and damage index range of the monolithic precast fiber recycled concrete shear wall at different stages were given.