Seismic Resilient Defecation Performance Analysis Of New Self-Centering Rocking Wall Structures

As a typical form of resilient structure,a recoverable deformation structure has the characteristics of small residual deformation,large energy dissipation capacity,small structural damage,and maximum retrofitting capacity after earthquakes.As a new type of recoverable deformation structure,a self-centering rocking wall can provide the self-centering ability of the structure by means of both prestressing tendons and self-weight.The energy dissipation ability of the structure is improved by the energy dissipation device.The special contact surface between the wall and the foundation is formed by relaxing the constraint of the bottom of the wall,and the "rocking" motion of the rocking wall with complex contact nonlinear behavior occurs under the action of external load.To explore the mechanism of recoverable deformation performance of self-centering rocking wall,this paper expounds from the following aspects:(1)Considering the self-centering rocking wall as a model of rigid body,the hysteretic performances of the self-centering rocking wall under horizontal loads are deduced theoretically and the hysteresis curves are drawn.Based on the existing test data,the correctness and accuracy of the hysteresis model is verified.The condition of self-centering rocking wall without residual deformation is determined by the hysteresis model,and the effects of initial prestress,diameters of prestressed tendons,yield strength of energy-dissipators,wall characteristic parameters,and axial compression ratio on the recoverable deformation performance of self-centering rocking wall are studied.The results show that the initial pre stress is increased by 2 times,the maximum bending moment of the rocking wall by about10 %;the diameter of the pre stress reinforcement by 20 %,the maximum bending moment of the rocking wall by about 15 %;the bending strength by 50 % and the maximum bending moment by about 5 %;the characteristic parameters of the wall by 25 %,the maximum bending moment by about 25 %;the axial pressure ratio by 50 % and the maximum bending moment by about 11 %.(2)According to actual force characteristics and contact nonlinear mechanical characteristics of the self-centering rocking wall,a numerical model of the self-centering rocking wall is established based on the Open SEES finite element analysis software,and a numerical simulation based on the proposed model is performed.With the aid of the existing test data,it is verified that the numerical model is sufficiently reliable and reliable.At the same time,the model can better express the mechanical response of prestressed tendons and energy-dissipators.The results show that the truss element method can accurately and effectively characterize the contact nonlinear characteristics,which is not different from the test results.(3)Based on the proposed hysteresis model,the corresponding parameters are analyzed and the influcing laws are obtained.For the key design parameters of the selfreplacement rocking wall such as the initial prestress of the prestressed tendons,the area of the prestressing tendons,the yield strength of the energy-dissipators,and the wall characteristic parameters,the parameters are analyzed on the basis of the established numerical model of the self-replacement rocking wall.The influcing laws for all parameters on the recoverable deformation capacity of the wall are analyzed through the hysteresis curves,self-centering coefficients,stiffness degradation,accumulated hsyteresis energy dissipation coefficients,and equivalent viscous damping ratios,etc.The results show that the finite element analysis results are in good agreement with the theoretical analysis results,and different parameters have different effects on bearing capacity,stiffness,equivalent damping and so on.(4)Seismic responses of the frame – rocking wall structures are analyzed using finite element method(FEM),and the seismic working mechanisms are investigated.By selecting the appropriate seismic waves,the dynamic response time history of an ordinary shear wall and a self-centering rocking wall is analyzed under minor,moderate,and major earthquakes,respectively,focusing on the compare of recoverable deformation performance of ordinary shear wall and self-centering rocking wall from the aspects of ductility coefficient,residual displacement ratio and vertex acceleration time history curves.Additionally,the static elastoplastic analysis and dynamic response time history analysis of a 9-story frame structure and a frame-rocking wall structure are performed,respectively.The results show that the interstory drift curves for the frame – rocking wall structure are better-distributed than that of the frame structure under static pushover loading;under seismic actions,the rocking wall cooperates with the structure,reciproc ating around the initial state of the structure,and can be reset in a short time.