Study On Seismic Performance Of Integrated Precast Shear Wall Filled With Ceramsite Concrete

As a main structural type of prefabricated buildings,precast concrete shear wall structures are widely used in high-rise residences,hotels and other buildings.In the design of concrete shear wall structures,in order to ensure the ductility of the structure or satisfy the structural requirements,structural openings will be set on those long shear walls.If these openings are not required according to the requirements of the building function,they will be usually blocked by lightweight blocks.Obviously,it is difficult to give full play to the assembly advantage of precast concrete structures due to the secondary masonry of the openings.In this case,a new type of integrated precast shear walls,which prefabricate the shear walls and the infill walls in the factory at the same time,will greatly increase the assembly rate of the precast shear wall structures.This paper studied the seismic performance of a new type of integrated precast shear wall with short wall limbs and ceramsite concrete infill walls through pseudo-static test,refined finite element modeling and parameter analysis.The main contents are as follows:(1)Three integrated precast coupled shear wall filled with ceramsite concrete were constructed,and the specimens were tested subject to cyclic lateral loading.The stress process,failure form,bearing and deformation capacity,stiffness and energy dissipation performance of the integrated precast shear wall were obtained.The influences of factors,such as the cross-section height of the coupling beam,the structural form of the infill wall and the shear wall,on the seismic performance of the integrated precast shear wall were studied.The test results showed that the bending failure of the wall limbs and the bending-shear failure of the coupling beams occured under the horizontal seismic action in the integrated precast shear wall.And as the cross-section height of the coupling beam increased,the failure form of the infill wall changes from corner failure to overall bending-shear failure.(2)Based on the ABAQUS finite element analysis platform,the integrated precast shear wall specimens,loading steel beams and ground beams were refinedly modeled using discrete models.The FE models selected reasonable material constitutive models.The boundary between the wall and the ground beam,the boundary between the shear wall and the infill wall were refinedly simulated by setting contact pairs.The hysteretic curve,failure mode,and longitudinal reinforcement strain of wall limbs obtained by the FE model were in good agreement with the results of the pseudo-static test,which verified the accuracy and applicability of the modeling method.(3)Based on the numerical model of the integrated shear wall with different infill wall structural and connection forms,the influence of 3 kinds of structural and connection forms between ceramsite concrete infill walls and shear walls on the load transfer mechanism and seismic performance of the integrated shear wall were analyzed,and the optimal design scheme of flexible connection was proposed.The influence of the design parameters on the seismic performance of the integrated precast shear wall were discussed by using the FE analysis.The parameters investigated included the width of the infill walls,the height of the shear wall limb section,the height of the coupling beam section,the strength of the concrete of the shear wall,the strength of the ceramsite concrete of the infilled wall,the diameter of the longitudinal reinforcement of the wall limb and the axial compression ratio of the wall limb section.(4)Based on the results of pseudo-static test and FE numerical analysis,the simplified calculation model of equivalent confined infill wall was used to analyze the integrated precast shear wall filled with ceramsite concrete with flexible connection.The horizontal shear capacity and lateral stiffness of the integrated precast shear wall were divided into two parts: the main shear wall and the equivalent confined ceramsite concrete infill wall.The calculation method of the initial stiffness and the horizontal shear capacity of the integrated precast shear wall filled with ceramsite concrete was proposed,and the applicability of the calculation method was verified by the FE numerical results.