为提升传统屈曲约束支撑的性能，特别是解决传统阻尼器在主震-余震型地震作用下发生断裂后无法为结构提供抗侧刚度和耗能能力的问题，提出了一种新型两阶段屈曲约束支撑（Two-stage Buckling-restrained Brace, 简称TS-BRB）。TS-BRB的耗能单元由三个横截面沿纵向渐变的Q235钢板串联组成，中部的耗能段在地震中首先发挥耗能作用，若该段发生断裂，约束单元中的限位卡槽能够确保端部耗能段继续工作，从而使TS-BRB具备较传统BRB更高的耗能能力。TS-BRB的滑移距离通过调整限位卡槽的长度来限制，从而满足结构减震设计的使用需求。TS-BRB的试验结果表明：该阻尼器的滞回曲线饱满，滞回曲线形状符合理论预期；TS-BRB具有明显的二阶段耗能特性，耗能单元的端部耗能段在中间耗能段断裂后可继续工作，断裂后的附加累计耗能为断裂前的138.41%。TS-BRB解决了传统BRB在断裂后随即失去承载和耗能能力的问题，能够为结构提供更大的耗能储备。最后使用ABAQUS建立实体单元数值模型，发现模拟与试验的滞回曲线吻合较好。

A novel two-stage buckling-restrained brace (TS-BRB) has been proposed to enhance the performance of conventional buckling-restrained braces (BRB), particularly addressing the problem that conventional BRB cannot provide lateral resistance and energy dissipation capacity to the structure after failure under the action of major-after shocks. The energy dissipation unit of TS-BRB consists of three Q235 steel plates in series with tapering cross-section along the longitudinal axis. The energy dissipation section in the middle plays the role of energy dissipation firstly during earthquake, and if this section breaks, the limit slot in the restraint unit ensures the rest of the energy dissipation section keeps working, thus giving TS-BRB a higher energy dissipation capacity than conventional BRB. The slipping distance of TS-BRB is limited by varying the length of the limit slot, enabling the brace to meet the requirements for structural damping design. Test results demonstrate that the hysteresis curve of the TS-BRB is saturated and the shape of the hysteresis curve is consistent with theoretical expectations. TS-BRB exhibits evident two-stage energy dissipation characteristics, with the end energy dissipation section continuing to operate after the middle energy dissipation section breaks. The additional accumulated energy dissipation after the fracture is 138.41% of that before the fracture. The TS-BRB provides a solution to the issue of conventional BRBs losing load-bearing and energy-dissipation capacity immediately after fracture and offers greater energy dissipation reserves for the structure. Finally，a numerical model was established in ABAQUS，which demonstrates that the hysteretic curve of numerical simulation agrees well with that of experiment．

国家自然基金(51878426)；科技部重点研发计划国际合作项目(2022YFE0113600)