碟簧-钢绞线组合自复位防屈曲支撑滞回性能OA北大核心CSTPCD

The self-centering buckling-restrained brace combined both disc springs and steel tendons(DT-SCB)was proposed to solve the shortage problem of the deformation ability of the traditional self-centering buckling-restrained brace(SCBRB).The steel tendons in series with combination disc springs are used to provide the self-centering force,and two parallel flat steel cores are responsible for dissipating seismic energy.The detailed configuration,working mechanism at different stages,and restoring force model of DT-SCB were introduced in this study.The finite element model was established,through which the effect of self-centering ratio αsc,the ratio of steel tendons and combination disc springs K1 and the ratio of self-centering unit and energy dissipation system K2 on the hysteretic behavior,self-centering level and energy dissipation capacity of DT-SCB were conducted,respectively.The results indicated that the proposed DT-SCB restoring force model agreed well with that from numerical simulation.No obvious failure characteristics were observed even if the maximum loading displacement(corresponding to the axial strain of 2.5%)was achieved.The hysteretic curve of DT-SCB was flag-shaped,with stable energy dissipation.The deformation ability of proposed DT-SCB was significantly greater than that of the conventional SCBRB with steel tendons.The maximum residual displacement sharply decreased with the increasing self-centering ratio,while the greater K1 weakened the control effect of αsc on residual deformation.The disc springs were prematurely flattened with an excessive ratio of self-centering system and energy dissipation system(K1≥2.0),which would reduce the deformation capacity of DT-SCB.The stiffness ratio K2 had a significant influence on the energy dissipation capacity of DT-SCB,and the equivalent viscous damper ratio of DT-SCB decreased with the increase of the stiffness ratio K2.The nonlinear dynamic analysis results of the braced frame subjected to severe earthquakes showed that DT-SCB can effectively reduce the maximum and residual inter-story drifts and improve the seismic performance of the frame.