Abstract This paper presents a Shuttle-Shaped Truss-Confined Buckling-Restrained Brace (SSTC-BRB) that is simply composed of a single steel tube core and a number of shuttle-shaped truss frames sharing a single external restraining tube. The SSTC-BRB, as an innovation in the external restraining system of the BRB, significantly improves the material utilization, and is particularly exposed externally to enhance the architectural aesthetics. The in-plane elastic buckling, load resistance and hysteretic responses of the SSTC-BRBs are investigated through Finite Element Model (FEM) that has been validated previously by using the test results of Truss-Confined Buckling-Restrained Brace (TC-BRB). Firstly, the elastic buckling performance of the SSTC-BRB is investigated and the obtained results indicate that there exist two possible elastic buckling modes for SSTC-BRBs, namely single-wave buckling and double-wave buckling modes. Secondly, the load resistance of SSTC-BRBs under monotonic axial compression is numerically analyzed, where the combined initial imperfections of SSTC-BRBs are involved particularly in the analysis. As a result, a lower limit of restraining ratio of SSTC-BRBs as a load-carrying type of BRBs is recommended, where the core could be fully yielded with its axial compressive strain reaches 0.02 without global instability of the SSTC-BRBs. Finally, the hysteretic performance of SSTC-BRBs subjected to axial compressive-tensile cyclic loads is studied numerically, and the corresponding lower limit of restraining ratio of SSTC-BRBs is proposed for them to be energy-dissipating types of BRBs. Those two lower limits of restraining ratios of the SSTC-BRBs corresponding to load-carrying and energy-dissipating types of BRBs could provide fundamental guidance for preliminary design of SSTC-BRBs.

中文翻译：

---

梭形桁架约束 BRB 的负载阻力和滞回响应

摘要 本文提出了一种梭形桁架约束屈曲约束支撑（SSTC-BRB），它由单个钢管芯和多个共享单个外部约束管的梭形桁架框架简单组成。SSTC-BRB作为BRB外约束系统的创新，显着提高了材料利用率，特别是外露，增强了建筑美感。通过有限元模型 (FEM) 研究 SSTC-BRB 的平面内弹性屈曲、负载阻力和滞后响应，该模型之前已使用桁架约束屈曲约束支撑 (TC-BRB) 的测试结果进行验证。首先，研究了 SSTC-BRB 的弹性屈曲性能，所得结果表明 SSTC-BRB 存在两种可能的弹性屈曲模式，即单波屈曲和双波屈曲模式。其次，数值分析了SSTC-BRBs在单调轴向压缩下的承载阻力，其中SSTC-BRBs的组合初始缺陷特别参与了分析。因此，建议将 SSTC-BRBs 作为承载类型的 BRBs 的约束比的下限设置为在 SSTC-BRBs 的全局不稳定性的情况下，其轴向压应变达到 0.02 时可以完全屈服核心。最后，数值研究了 SSTC-BRBs 在轴向压拉循环载荷作用下的滞后性能，并提出了相应的SSTC-BRBs抑制比下限为耗能型BRBs。SSTC-BRBs 承载型和耗能型 BRBs 的这两个约束比下限可以为 SSTC-BRBs 的初步设计提供基本指导。