Seismic Performance Of Precast Shear Walls With Unconnected Vertical Distributed Reinforcement

To solve the fabrication and quality problems of precast shear wall caused by the sleeve grouting connection method,a new type of precast shear wall with unconnected vertical distributed reinforcements(hereafter referred to as SGBL shear wall)was developed.The longitudinal reinforcements in the boundary elements of SGBL shear wall were enlarged to ensure structural safety performance due to the disconnection of the vertical distributed reinforcements.The main research contents and innovative achievements of this paper were as follows:One shear wall structure project was selected as the research object for internal force analysis.Then three high wall specimens and five low wall specimens were selected as typical shear walls for seismic performance tests.The variation characteristics of seismic performance such as failure mode,bearing capacity,ductility and stiffness degradation were determined.The slip of horizontal interface increased under the axial compression ratio of 0.1.Both failure modes of SGBL shear wall specimens and cast-in-place shear wall specimens were bending failure modes under the axial compression ratio of 0.3.The bearing capacities were basically the same and the ductility coefficients of SGBL shear wall specimens were a bit higher than that of cast-in-place shear wall specimens.The failure mode of SGBL shear wall specimen was shear failure mode under the axial compression ratio of 0.6 and the diagonal reinforcements were taken full advantage of.Finite element models of SGBL shear walls were established by the software of ABAQUS,parameter analysis was conducted to further analyze the effect on the seismic performance of SGBL precast shear wall by vertical reinforcements and diagonal reinforcements.The analysis results showed that the ratio of unconnected vertical reinforcements could be constructional reinforcements which had little effect on the mechanical performance of SGBL shear wall.The improvement of seismic performance on SGBL shear walls by diagonal reinforcements was limited under bending failure mode.The diagonal reinforcements could be only arranged in SGBL shear wall with high requirement of shear performance.The safety performance of SGBL shear wall structure in the case of seldomly occurred earthquake was firstly verified by the elastic-plastic time history analysis.The analysis results showed that SGBL shear wall structure model exhibited better seismic performance than the corresponding cast-in-place shear wall structure model,which indicated that SGBL shear wall structure met the safety requirement of seismic performance.Design methods of SGBL shear wall were proposed by the results of experimental study and simulation analysis.Quantitative analysis was conducted to consider the weakening effect on the bearing capacity of SGBL shear wall caused by the slip of horizontal interface.The design methods of the cracking capacity and the deformation performance of SGBL shear wall were proposed.Suggestions on the inclination angles of diagonal reinforcements of SGBL shear wall were given by the theory of softened truss model.Finally,the problem of reinforcement waste by traditional design method of intersecting boundary elements was solved by the design concept of combined shear wall.