Research On New Hybrid Assembly Technology For Precast Concrete Shear Wall Structure

Building industrialization, as the important development direction of building industry, has become the focus of attention of the industry along with the transformation and upgrading of building industry. The precast concrete structure is an important content in building industrialization. With regard to the abundant applications of shear wall structures in moderate- and high- rise building in our country, especially in the residential housing under heavy demand, precast concrete shear wall structure has been the developing emphasis and several typical precast concrete shear wall technologies have been put forward.In order to comply with the design concept of emulating, based on the hybrid system, Emulative hybrid shear wall system (EHSW) has been proposed. EHSW combines three technologies including post-tensioned unbonded prestressing, partially debond of grouted reinforcing bar, and overlapped closed stirrup to overcome the pivotal problems such as premature cracking and concrete damage concentration, which exist in present precast concrete shear walls in comparison with monolithic cast-in-place concrete shear wall. The model experiments, finite element analysis, and theoretical analysis are carried out to grasp the seismic performance of EHSW. The main work and conclusions are as follows:(1) Eight EHSW and one reference monolithic cast-in-place models of full scale are fabricated and tested under low-cyclic reversed lateral loading. The design parameters, such as area of unbonded prestressed tendons, initial prestressing stress in the tendons, debonded length of grouted reinforcing bar and axial loading ratio, are considered in the experiments. The failure pattern, strength, stiffness, ductility, energy dissipation and residual displacement are analyzed and the impact of design parameters on the seismic performance of EHSW models are obtained.(2) Finite element models reflecting the tested EHSW models are established and the analysis results are compared to the measured results to prove the accuracy of the finite element models. Parametric analysis based on established finite element model is conducted to supplement the experiment results.(3) Based on present calculation methodologies of flexural members, the force and displacement values at feature points, such as cracking point, yielding point, ultimate point and failure point, are determined. The calculated results are compared to the measured results and the calculation methods are modified by numerical fitting method according to the impact rule of design parameters.(4) With regard to the shape of measured hysteretic curves and skeleton curves, four-line model is proposed and restoring force mathematic model is established based on the modified strength and stiffness calculation methods. The four-line model and restoring force mathematic model have good accordance with the measured results.The seismic performance of EHSW is obtained and the relevant calculation method as well as hysteretic model are proposed based on the accomplished experiment and analysis work. The achievements establish data and theoretic basis for further research and engineering application of EHSW.