Experimental Study On Seismic Performance Of Composite Shear Walls With Pec Columns

PEC composite structure combines the characteristics of the steel structure and the reinforced concrete structure,which improves the construction speed and structural bearing capacity,and effectively improves the seismic resistance and fire resistance performance,thus attracting more attention.Steel reinforced concrete shear walls have been widely used in super high-rise building structures,but shear walls with PEC columns as edge restraining members are relatively rare in practical engineering applications.This combination of shear walls is improved due to the presence of PEC columns In order to accelerate the industrialization process by saving the prefabricated degree and saving some molds,it can play an important advantage in technology and economy.In this paper,through the seismic performance test and numerical simulation analysis of composite shear walls with PEC columns,it is intended to provide a reference for the design and construction of such composite shear walls.In this paper,two composite shear wall specimens with PEC columns as edge-constrained members under different axial compression ratios are designed and fabricated for low-cycle cyclic loading.C35 is adopted in the strength grade of the two specimens,the shear-span ratio is 2,and the axial compression ratio is 0.147 and 0.221 respectively.By observing the failure process of the specimens,the seismic performance indexes of the Composite Shear Wall,such as hysteretic behavior,bearing capacity,stiffness degradation,ductility and energy dissipation,are analyzed.The results show that with the increase of axial compression ratio from 0.147 to 0.221,the cracking load increases by 40.75%,the yield load and peak load increase by 24.8% and 10.75% respectively,and the degradation Coefficient of bearing capacity of SW-1 is stable during the whole loading process,at the end of the loading period,SW-2 suddenly dropped to 0.934,and then to 0.87.With the increase of axial compression ratio,the degradation coefficient of bearing capacity decreased.The ductility coefficients of the two specimens are 3.55 and 3.28 respectively,and the equivalent viscous damping coefficients of the structure are between 27.77% and 35.41% With the increase of axial compression ratio,the PEC columns play a restraining role in the later loading period,and the energy consumption increases obviously,4%,11% and 22% per cycle.The yield sequence of the specimens is: The outer flange of columns on both sides of the wall,the column Web,the two ends of horizontal reinforcement at the root of the wall,and the lower part of longitudinal reinforcement of the wall.On the basis of the test,the finite element analysis and related parameters of the composite shear wall were studied,and the effects of the axial compression ratio,the thickness of the steel flange and the diameter of the wall distribution bars on the seismic performance of the specimen were analyzed.When the axial compression ratio is 0.5 and 0.6,the bearing capacity decreases by 21.7% and 31.3% respectively,and the failure mode changes from shear failure to compression failure.When the axial compression ratio increases to 0.6,the ductility decreases by 28.6%.The increase of flange thickness can improve the ultimate bearing capacity and reduce the influence of slippage.It is not obvious that changing the diameter of the distributed reinforcement in the wall has an effect on the bearing capacity of the members.