组合碟簧自复位防屈曲支撑滞回性能试验

为控制防屈曲支撑(BRB)的残余变形，采用碟簧自复位系统(DS)和BRB并联形成自复位防屈曲支撑(SBRB)。通过拟静力试验考察组合碟簧刚度、端部连接、复位比率等对SBRB滞回性能的影响。结果表明：与BRB相比，SBRB的残余变形大幅降低；SBRB表现出旗型的滞回曲线，试验后期钢板支撑受拉断裂，其他部件保持完好；SBRB试件中DS部分和BRB部分分别是承载力和累积耗能的主要来源；由于组合碟簧间的摩擦等作用，DS部分的耗能占整个SBRB耗能的23%～36%;其他构造相同时，采用组合碟簧刚度较大的DS部分启动后承载力增幅较多，且DS部分启动力较大的复位比率也较大，残余变形更小。总体上，端部连接形式对残余变形影响不大，刚接SBRB试件因承受额外的端部弯矩，钢板支撑断裂更早，铰接SBRB试件表现出更好的耗能能力。随复位比率增大，SBRB的残余变形逐渐减小，为有效地控制支撑残余变形，同时避免对DS部分要求过高，复位比率宜取0.7～0.9。

Tests on the hysteretic behavior of self-centering buckling-restrained braces with stacked disc springs

The self-centering buckling-restrained brace (SBRB) was formed by making a self-centering system consisting of stacked disc springs (DS) and a buckling-restrained brace (BRB) work in parallel to control the residual deformation of BRB. Quasi-static tests were done to examine the effects of stiffness of stacked springs, end connections, self-centering ratios, etc. on the hysteretic behavior of SBRBs. The tests revealed that, compared with BRBs, the residual deformations of SBRBs were reduced greatly. SBRBs exhibited flag-shaped hysteretic curves, and in the later stage of tests, the steel plate brace underwent tensile failure while other components remained intact. The bearing capacity and energy dissipation capacity of SBRBs are mainly from the DS parts and BRB parts, respectively. Approximately 23%-36% energy dissipation in SBRBs is from the DS parts due to the friction between stacked springs. When the other constructional details remained the same, the DS parts with a higher stiffness of springs had a greater increase in bearing capacity after starting, and the DS parts with a higher starting force also had a higher self-centering ratio and smaller residual deformations. On the whole, the end connections had little effect on the residual deformations. The tension fracture of steel plate brace occurred earlier in the SBRB with rigid end connections due to bearing additional bending moments, while the SBRBs with pin end connections exhibited better energy dissipation. With the increase of self-centering ratios, the residual deformations of SBRBs reduced gradually and the appropriate ratios of SBRBs should be kept within 0.7-0.9 to efficiently control residual deformations and to avoid excessive demand of DS parts.