Abstract Shear-critical reinforced concrete structures such as older columns with insufficient transverse reinforcement details or short columns are found to be vulnerable to earthquake loading. Meanwhile, in the aggressive environment, RC structures tend to be more vulnerable to earthquake since corrosion of reinforcements will cause deterioration of the material properties. In the present study, a new framework is proposed for seismic fragility analysis of shear-critical structures with the consideration of corrosion effects. A new model for corroded concrete columns is proposed which can account for shear performance deterioration due to corrosion and the seismic flexure-shear interaction (FSI) behaviors. The modified Ibarra-Medina-Krawinkler deterioration model is adopted to simulate the shear response in order to capture shear strength and stiffness deterioration as well as pinching behavior of corroded shear-critical columns. The deteriorating material properties are determined based on corrosion modeling methods, and the corrosion level differences between transverse and longitudinal reinforcement are addressed. Furthermore, the proposed framework adopts time-variant structural capacities as obtained from the proposed numerical model in the fragility analysis. The developed framework is demonstrated with a shear-critical bridge column. The results clearly indicate the adverse effects of corrosion on seismic fragility of shear-critical columns, especially at severer damage states. Using flexure model and time-invariant capacity index will underestimate seismic fragility compared with the results obtained using the proposed method.

中文翻译：

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考虑腐蚀退化效应的剪切临界混凝土柱抗震脆性分析

摘要 剪切临界钢筋混凝土结构，例如横向钢筋细节不足的旧柱或短柱，容易受到地震荷载。同时，在侵蚀性环境中，钢筋混凝土结构更容易受到地震的影响，因为钢筋的腐蚀会导致材料性能的恶化。在本研究中，提出了一种新的框架，用于考虑腐蚀效应的剪切临界结构的地震脆性分析。提出了一种腐蚀混凝土柱的新模型，该模型可以解释由于腐蚀和地震弯曲 - 剪切相互作用 (FSI) 行为引起的剪切性能恶化。采用改进的 Ibarra-Medina-Krawinkler 退化模型来模拟剪切响应，以捕获腐蚀的剪切临界柱的剪切强度和刚度退化以及收缩行为。基于腐蚀建模方法确定恶化的材料特性，并解决横向和纵向钢筋之间的腐蚀水平差异。此外，所提出的框架采用了从脆弱性分析中所提出的数值模型中获得的时变结构能力。开发的框架用剪切临界桥柱进行了演示。结果清楚地表明腐蚀对剪切临界柱的地震脆性的不利影响，特别是在更严重的损坏状态下。