This study explores the flexural behavior of reinforced concrete (RC) columns strengthened with near surface mounted (NSM) shape memory alloy (SMA) bars or carbon fiber reinforced polymer (CFRP) bars. Seven RC column specimens were designed and fabricated to study the influence of different variables on the flexural response of the strengthened columns. These parameters include type of NSM reinforcement (SMA bars or CFRP bars), ratio of NSM reinforcement, and effect of CFRP jacketing. The columns were tested under cyclic lateral loading with constant axial force. The flexural behavior of each specimen was examined in terms of peak load, failure load, drift ratios, displacement ductility, stiffness degradation, energy dissipation, and seismic damage index. The experimental results indicate that strengthening of RC columns with NSM SMA or CFRP bars improves the flexural behavior of the columns through increasing the lateral load capacity, reducing the stiffness degradation and increasing the cumulative energy absorption up to failure. Further enhancement in the lateral response of RC columns was obtained by combining NSM bars and CFRP jacketing as the later provides an additional confinement to the critical sections of the test specimens.

中文翻译：

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通过近表面安装的 SMA 和 CFRP 钢筋增强 RC 柱的抗弯能力

本研究探讨了用近表面安装 (NSM) 形状记忆合金 (SMA) 钢筋或碳纤维增强聚合物 (CFRP) 钢筋加固的钢筋混凝土 (RC) 柱的弯曲行为。设计并制造了七个钢筋混凝土柱试件，以研究不同变量对加固柱弯曲响应的影响。这些参数包括 NSM 钢筋的类型（SMA 钢筋或 CFRP 钢筋）、NSM 钢筋的比率以及 CFRP 护套的效果。这些柱子在具有恒定轴向力的循环横向载荷下进行了测试。从峰值载荷、破坏载荷、漂移比、位移延展性、刚度退化、能量耗散和地震损伤指数方面检查每个试样的弯曲行为。实验结果表明，用 NSM SMA 或 CFRP 钢筋加固 RC 柱可通过增加横向承载能力、减少刚度退化和增加直至失效的累积能量吸收来改善柱的弯曲行为。通过结合 NSM 钢筋和 CFRP 护套，可以进一步增强 RC 柱的横向响应，因为后者为试样的关键部分提供了额外的限制。