| Frame structures tends to damage at the ends of columns on some floors due to the collapse of the soft story of the structure under the strong ground motion.This type of failure is inconsistent with the expected that yield first occure at beam ends in the design To improve the frame structure failure form,the original frame structure is connected to a rigid wall then form a rocking wall system.Under the ground motion,the rocking wall panel rotates around the bottom rotation center and forces the frame structure to move more uniformly between layers,avoiding the soft storey damage,forming an overall yield mechanism,and improving the seismic performance of the structure Aiming at the improvement of the existing rocking wall system,this paper proposes a frame-rocking wall system which is suitable for prefabricated external wall panels and has friction dampers between the gaps between the wall panels.This paper analyzes the seismic performance of the system through experiments and numerical simulations.The main research contents are as follows:(1)Study the connection method of the external wall panel to the frame and the structure of the wall panel.A friction damper is installed between the gaps in the wall to study the effect of different friction materials and bolt pretension forces on the performance of the friction damper.A quasi-static test was performed on the frame-rocking wall to study the rotation capacity and hysteretic energy dissipation performance of the system.The test results show that the system has the advantages of stable hysteresis performance,strong energy consumption capacity,and convenient repair after the earthquake(2)According to the pseudo-static test results of the single-layer friction damper frame-rocking wall system,the material parallel constitutive model in OpenSees was used to simulate the properties of the system.The gradient descent method is used to accelerate the determination of parameters in the simulation process,and the simulation results that meet the test are obtained and applied to the actual building simulation.(3)Study the contribution of frame-rocking wall system with friction damper to the stiffness of the frame structure as a whole and between layers,and the numerical analysis model of the structure is determined based on the simulation results of the single layer system.Two typical buildings during the Northridge earthquake were selected for the reconstruction of the frame-rocking wall system with friction damper,and numerical simulation analysis was performed on the reconstructed buildings.The effects of different stiffness contribution coefficients,stiffness distribution coefficients of friction dampers and rocking walls,and different load distributions on the seismic performance of structures were studied through parameters such as the drift concentration factor,the story drift,and the friction damper energy dissipation ratio The dynamic time history analysis of 20 seismic waves with a probability of 2%over 50 years and 10%with a probability of over 50 years shows that the frame-rocking system with friction damper can effectively improve the seismic performance of the structure.(4)The seismic design of the frame-rocking system with friction damper was carried out through a displacement-based design method.Time-history analysis of the designed structure using 20 designed seismic waves verified the feasibility of the design method and proved the reasonably designed frame-rocking system with friction damper can achieve specific seismic targets. |
