A new type of external substructure to upgrade existing reinforced concrete frames (RCFs) is presented in this paper, namely, a self‐centering precast bolt‐connected steel‐plate reinforced concrete buckling‐restrained brace frame (SC‐PBSPC BRBF). The upgrade mechanism and three‐dimensional simulation model were analyzed based on relevant experiment validations. A quasistatic analysis and parameter study was conducted using 21 scenarios to compare the upgrading effects of the outside substructure. Afterwards, a stiffness‐based design procedure was developed and modified for this external substructure, including macro‐demand analysis, partial component design, and overall structural evaluations. Dynamic analyses were also performed on a frame building for five cases, before and after strengthening. The proposed numerical model reflected the precast characteristics and displayed the ideal fitting accuracy. The external assembled brace provided sufficient initial stiffness and energy dissipation capacity, while the external prestressed tendon decreased residual displacements and facilitated self‐centering of the whole structure. The analyses illustrated that the damage to the existing RCF was transferred and seismic demands were significantly reduced within limitations, accompanied with greater capacity reliability. This research provides a reference for the practical applications of the external upgrading substructures in earthquake‐prone areas.

中文翻译：

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基于SC‐PBSPC BRBF子结构的钢筋混凝土框架抗震性能研究

本文提出了一种用于升级现有钢筋混凝土框架（RCF）的新型外部子结构，即一种自定心的预制螺栓连接钢板-钢筋混凝土屈曲约束支撑框架（SC-PBSPC BRBF）。基于相关实验验证，分析了升级机制和三维仿真模型。进行了准静态分析和参数研究，使用了21种方案，以比较外部子结构的升级效果。之后，针对此外部子结构开发并修改了基于刚度的设计程序，包括宏观需求分析，局部零件设计和整体结构评估。在加固之前和之后，还对五个案例的框架进行了动态分析。所提出的数值模型反映了预制特征并显示了理想的拟合精度。外部组装的支架提供了足够的初始刚度和能量消散能力，而外部预应力筋减少了残余位移并促进了整个结构的自定心。分析表明，对现有RCF的损害已经转移，并且在有限的范围内大大降低了地震需求，同时具有更高的容量可靠性。该研究为地震多发地区外部升级子结构的实际应用提供了参考。而外部预应力筋减少了残余位移并促进了整个结构的自定心。分析表明，对现有RCF的损害已经转移，并且在有限的范围内大大降低了地震需求，同时具有更高的容量可靠性。该研究为地震多发地区外部升级子结构的实际应用提供了参考。而外部预应力筋减少了残余位移并促进了整个结构的自定心。分析表明，对现有RCF的损害已经转移，并且在有限的范围内大大降低了地震需求，同时具有更高的容量可靠性。该研究为地震多发地区外部升级子结构的实际应用提供了参考。