ABSTRACT

For inland cities with high concentration of carbon dioxide in the air, the seismic performance of RC structures deteriorates over time. In this study, a previously developed concrete carbonation and corrosion model was introduced to the framework of seismic fragility analysis to investigate the effects of environmental factors on the seismic performance of RC structures, considering carbon dioxide, humidity, and temperature. An approach to quantify the effects of these environmental effects on the time-dependent fragility of deteriorated RC buildings in the inland atmosphere environment was proposed. A four-story three-bay RC structure was analysed as a case study. Pushover analysis was performed to identify the damage limits of the structure as a function of the exposure time (0, 25, 50, 75 and 100 years). Fragility curves of the structure at different exposure times were developed based on the time-dependent seismic demands and predefined limit states. The results show that the structure deteriorates when exceeding the design life of durability. In general, the damage to the deteriorated structure increases with time and intensity of ground motions. In particular, the margin between severe damage and collapse decreases significantly over time. This means that aging structures are likely to collapse suddenly after severe damage occurs. Therefore, the time-dependent seismic performance of the aging structures in the inland cities should be carefully considered.

摘要

对于空气中二氧化碳浓度高的内陆城市，RC结构的抗震性能会随着时间的推移而恶化。在这项研究中，将先前开发的混凝土碳化和腐蚀模型引入地震脆弱性分析框架，以研究考虑二氧化碳、湿度和温度的环境因素对 RC 结构抗震性能的影响。提出了一种量化这些环境影响对内陆大气环境中退化 RC 建筑物随时间变化的脆弱性的影响的方法。以四层三开间钢筋混凝土结构为例进行分析。进行 Pushover 分析以确定结构的损坏极限作为暴露时间（0、25、50、75 和 100 年）的函数。根据时间相关的地震需求和预定义的极限状态，开发了结构在不同暴露时间的脆性曲线。结果表明，当超过耐久设计寿命时，结构会发生劣化。一般来说，对损坏结构的破坏随着时间和地震动强度的增加而增加。特别是，随着时间的推移，严重损坏和倒塌之间的界限会显着减小。这意味着老化的结构很可能在发生严重损坏后突然倒塌。因此，应认真考虑内陆城市老化结构的时变抗震性能。结果表明，当超过耐久设计寿命时，结构会发生劣化。一般来说，对损坏结构的破坏随着时间和地震动强度的增加而增加。特别是，随着时间的推移，严重损坏和倒塌之间的界限会显着减小。这意味着老化的结构很可能在发生严重损坏后突然倒塌。因此，应认真考虑内陆城市老化结构的时变抗震性能。结果表明，当超过耐久设计寿命时，结构会发生劣化。一般来说，对损坏结构的破坏随着时间和地震动强度的增加而增加。特别是，随着时间的推移，严重损坏和倒塌之间的界限会显着减小。这意味着老化的结构很可能在发生严重损坏后突然倒塌。因此，应认真考虑内陆城市老化结构的时变抗震性能。