Abstract Self-centering buckling-restrained braces (SC-BRBs) utilizing the re-centering potential of shape memory alloy (SMA) bars are used to control the excessive residual drift response of braced frames under seismic loading. The effectiveness of SC-BRBs in controlling the seismic response of a structure largely depends on the relative strength and stiffness of SMA bars and BRB core plates. This study is focused on determining the optimum length and prestressing force levels in SMA bars to maximize the hysteretic energy dissipation and re-centering behavior of SC-BRBs and evaluating the drift response of a medium-rise braced frame under near-field earthquake excitations. The seismic performance of SC-BRBs has been numerically investigated at both component (local) and frame (global) levels using a computer software OpenSees. Both length and prestressing force in SMA rods are varied in the numerical models to evaluate the axial resistance and hysteretic energy dissipation potential of SC-BRBs. The hysteretic response of SC-BRBs is compared with that of conventional BRBs. Nonlinear dynamic analysis has been conducted on a 9-story braced frame equipped with SC-BRBs as well as BRBs under forty near-field ground motion records. The seismic drift response of braced frames equipped with SC-BRBs with different prestressing force levels is compared with that of BRBF. Based on the findings of this study, the optimum geometric parameters of SMA bars have been proposed for the design of SC-BRBs.

中文翻译：

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采用SMA优化设计参数的SC-BRBs近场地震性能

摘要 利用形状记忆合金（SMA）杆的再定心潜力，自定心屈曲约束支撑（SC-BRBs）用于控制支撑框架在地震荷载作用下的过度残余漂移响应。SC-BRB 控制结构地震响应的有效性在很大程度上取决于 SMA 钢筋和 BRB 芯板的相对强度和刚度。本研究的重点是确定 SMA 钢筋的最佳长度和预应力水平，以最大限度地提高 SC-BRB 的滞后能量耗散和重新定心行为，并评估中层支撑框架在近场地震激发下的漂移响应。已经使用计算机软件 OpenSees 在组件（局部）和框架（全局）级别对 SC-BRB 的抗震性能进行了数值研究。SMA 杆的长度和预应力在数值模型中都不同，以评估 SC-BRB 的轴向阻力和滞后能量耗散潜力。将 SC-BRB 的滞后响应与传统 BRB 的滞后响应进行比较。对装有 SC-BRB 和 BRB 的 9 层支撑框架在 40 次近场地震动记录下进行了非线性动力分析。将装有不同预应力水平的SC-BRBs的支撑框架的地震漂移响应与BRBF的地震漂移响应进行了比较。根据本研究的结果，提出了用于 SC-BRB 设计的 SMA 杆的最佳几何参数。将 SC-BRB 的滞后响应与传统 BRB 的滞后响应进行比较。对装有 SC-BRB 和 BRB 的 9 层支撑框架在 40 次近场地震动记录下进行了非线性动力分析。将装有不同预应力水平的SC-BRBs的支撑框架的地震漂移响应与BRBF的地震漂移响应进行了比较。根据本研究的结果，提出了用于设计 SC-BRB 的 SMA 杆的最佳几何参数。将 SC-BRB 的滞后响应与传统 BRB 的滞后响应进行比较。对装有 SC-BRB 和 BRB 的 9 层支撑框架在 40 次近场地震动记录下进行了非线性动力分析。将装有不同预应力水平的SC-BRBs的支撑框架的地震漂移响应与BRBF的地震漂移响应进行了比较。根据本研究的结果，提出了用于设计 SC-BRB 的 SMA 杆的最佳几何参数。