Study On Seismic Behavior Of Precast Recycled Aggregate Concrete Shear Wall With Simplified Bolted Connection

Promoting low-carbon building material and green construction method is an important way to help achieve peak carbon dioxide emissions and carbon neutrality in the construction industry.In order to improve the assembly efficiency and low-carbon benefit of precast concrete shear wall(PCSW),a new precast recycled aggregate concrete shear wall(PRACSW)with simplified bolted connection for horizontal joint is proposed.The seismic behavior of PRACSW with simplified bolted connection was deeply and systematically researched by using experiment,finite element and theories analysis methods.The main findings are as follows.(1)A direct shear test loading device for grouting joint was developed.Six keyed joints and two plain joints of recycled aggregate concrete were designed to conduct the direct shear test.The evolution law of shear behavior was found.The shear mechanism for grouting joints of recycled aggregate concrete without shear reinforcement was revealed.Formulas to calculate shear bearing capacity of recycled aggregate concrete plain joint and keyed joint were proposed.Simplified shear-slip model of recycled aggregate concrete grouting joint was proposed.The shear key can effectively improve the shear capacity of recycled concrete grouting joint.(2)Four PRACSWs with simplified bolted connection and two cast-in-place shear walls were designed for quasi-static loading test.The influence laws of experimental parameters(i.e.,shear span-to-depth ratio,axial compression ratio,RCA replacement ratio)on the seismic behavior(i.e.,failure mode,hysteretic loop,skeleton curve,deformation of characteristic point,bearing capacity of characteristic point,strength degradation,stiffness degradation,ductility,energy dissipation,distribution of strain and residual deformation)were revealed.The strength of PRACSW with simplified bolted connection is equal to that of cast-in-place shear wall.The design objective of strong joint and weak member can be achieved with the simplified bolted connection.(3)The accurate finite element model of PRACSW with simplified bolted connection was built.The simulation results are in agreement with the test results.A total of 110 cases were simulated.The influence laws of key design parameters on the seismic behavior of PRACSW with simplified bolted connection were revealed.A grey correlation analysis was conducted to evaluate the parametric sensitivity of the bearing capacity of PRACSW with simplified bolted connection.(4)Based on the Park-Ang damage model,a modified damage model applied to PRACSW was proposed.The computational formula of combined coefficient was put forward.The statistical analysis of related test results of thirty PRACSWs was conducted.The damage index at failure point which is calculated with the proposed modified damage model has a mean value near 1.0,satisfying the limit requirement of damage model.The damage indexs corresponding to different damage states and performance levels were proposed.(5)The formulas to calculate flexural bearing capacity of PRACSW with simplified bolted connection were proposed based on the plane section assumption.The formulas to calculate shear bearing capacity of oblique section and joint were proposed based on the superposition method.The calculation formulas of bearing capacity were conservative which was verified by results of test and finite element.At last,the design methods of reinforcements through equal strength,high-strength bolts and steel connectors were proposed.