Data for CAIT-UTC-REG2B - Sustainable, Rapid Repair Utilizing Advanced Cementitious Materials

Durability and resilience of a structure are typically considered separately, as they address structural performance under different types of loads. A systematic framework for combined durability-resilience assessment of an RC bridge column is presented in this article. Corrosion of steel reinforcement is the main deterioration mechanism considered for durability evaluation, and earthquakes are assumed to be the primary hazard for resilience assessment. An example bridge column with two types of cover materials – conventional concrete and ductile fiber-reinforced concrete – is considered in our study. The ductile fiber-reinforced concrete provides better durability than the conventional concrete, resulting in lower rebar mass loss at a given time. Fick’s second law of diffusion is used to model the corrosion initiation phase. A pitting corrosion model, accounting for the effects of cracking on the corrosion rate, is considered for the corrosion propagation phase. Seismic fragility curves are constructed by nonlinear dynamic analysis, incorporating the rebar mass loss, at discrete times during the life span of the bridge. The results indicate that corrosion of reinforcement increases the vulnerability of the bridge column to seismic hazard. Furthermore, better durability provided by the ductile fiber-reinforced concrete cover leads to improved seismic resilience.

结构的耐久性与恢复力通常被分开考量，因其分别对应不同荷载类型下的结构性能表现。本文提出了一套用于钢筋混凝土（Reinforced Concrete，RC）桥梁柱耐久性-恢复力联合评估的系统性分析框架。本次耐久性评估以钢筋锈蚀作为主要劣化机制，恢复力评估则以地震作为首要灾害类型。本研究选取了采用两类保护层材料的桥梁柱作为分析示例：普通混凝土与延性纤维增强混凝土（ductile fiber-reinforced concrete）。延性纤维增强混凝土的耐久性优于普通混凝土，可在既定服役时刻降低钢筋的质量损失。本研究采用菲克第二扩散定律模拟锈蚀起始阶段，针对锈蚀扩展阶段，则采用考虑了开裂对锈蚀速率影响的点蚀模型。通过非线性动力分析构建地震易损性曲线，分析过程中纳入桥梁服役寿命期间离散时间点的钢筋质量损失变量。研究结果表明，钢筋锈蚀会加剧桥梁柱在地震灾害下的易损性；此外，延性纤维增强混凝土保护层所提供的更优耐久性，可有效提升桥梁柱的地震恢复力。