碟簧-钢绞线组合自复位防屈曲支撑滞回性能

为解决传统自复位防屈曲支撑变形能力不足的问题，提出一种碟簧-钢绞线组合自复位防屈曲支撑（Disc Spring-Steel Tendon Self-centering Buckling-restrained Brace，DT-SCB）. DT-SCB采用串联的钢绞线及碟簧组成的复位系统提供复位能力，通过两个并联的一字型内芯耗散地震能量. 介绍了DT-SCB构造、各阶段工作机理及恢复力模型. 建立有限元模型，研究复位比率αsc、钢绞线与碟簧组刚度比K1、复位元件与耗能系统刚度比K2等参数对支撑滞回性能、自复位效果及耗能能力的影响. 研究结果表明：提出的DT-SCB恢复力模型与模拟结果吻合较好，所有DT-SCB支撑在最大加载位移（2.5%轴向应变）内未发生明显破坏，支撑滞回曲线呈旗帜型特征，且具有稳定的耗能能力. 相比于传统基于钢绞线的自复位防屈曲支撑，DT-SCB具有更强的变形能力. DT-SCB最大残余变形随复位比率αsc提高显著减小，而刚度比K1的增加会削弱复位比率对支撑残余变形的控制效果. 钢绞线与碟簧组刚度比过大（K1≥2.0）会导致碟簧组提前被压平，进而降低支撑的变形能力. DT-SCB耗能能力受刚度比K2影响较大，其等效黏滞阻尼比随刚度比K2的增大而降低. 罕遇地震下支撑-框架结构非线性时程分析结果表明，DT-SCB可以有效减少结构的最大层间位移角及残余层间位移角，提高结构抗震性能.

Hysteretic Performance of Disc Spring-Steel Tendon Self-centering Buckling-restrained Brace

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.