Abstract

Significant research efforts have been recently invested towards the evaluation of chloride-induced deterioration effects on the seismic vulnerability of aging highway bridges. Furthermore, when located in coastal cities with increased urbanisation or near shipyards, bridge structures may also be subjected to potentially high levels of carbon dioxide emissions. Consequently, the physicochemical process resulting from simultaneous ingress of chlorides and concrete carbonation may lead to accelerated corrosion deterioration of reinforced concrete components, as evidenced in past experimental tests. Nevertheless, little attention has been paid towards modelling this joint influence of chloride and carbonation-induced corrosion deterioration on strength degradation of bridge components. The present study proposes a numerical iterative scheme to evaluate the simultaneous impact of these deterioration mechanisms on the seismic response and bridge fragility. The proposed framework is demonstrated on a case-study multi-span continuous steel girder bridge in Central and Southeastern United States. Results reveal a considerable influence on the corrosion initiation time and seismic vulnerability under the concurrent carbonation and chloride ingress. Furthermore, this study also conducts a systematic exploration of uncertainty at different stages of the deterioration process. This exercise helps provide recommendations on balancing between computational complexity and accuracy of seismic fragility predictions.

摘要

最近投入了大量的研究工作来评估氯化物引起的老化对公路桥梁地震脆弱性的影响。此外，当位于城市化进程加快的沿海城市或造船厂附近时，桥梁结构也可能受到潜在高水平二氧化碳排放的影响。因此，由氯化物和混凝土碳化同时进入引起的物理化学过程可能导致钢筋混凝土构件的加速腐蚀恶化，正如过去的实验测试所证明的那样。然而，很少有人关注氯化物和碳化引起的腐蚀恶化对桥梁构件强度退化的联合影响建模。本研究提出了一种数值迭代方案来评估这些劣化机制对地震响应和桥梁脆弱性的同时影响。所提出的框架在美国中部和东南部的一个案例研究多跨连续钢梁桥上进行了演示。结果表明，在碳化和氯化物同时进入的情况下，腐蚀起始时间和地震脆弱性有相当大的影响。此外，本研究还对劣化过程不同阶段的不确定性进行了系统探索。该练习有助于就地震脆弱性预测的计算复杂性和准确性之间的平衡提供建议。所提出的框架在美国中部和东南部的一个案例研究多跨连续钢梁桥上进行了演示。结果表明，在碳化和氯化物同时进入的情况下，腐蚀起始时间和地震脆弱性有相当大的影响。此外，本研究还对劣化过程不同阶段的不确定性进行了系统探索。该练习有助于就地震脆弱性预测的计算复杂性和准确性之间的平衡提供建议。所提出的框架在美国中部和东南部的一个案例研究多跨连续钢梁桥上进行了演示。结果表明，在碳化和氯化物同时进入的情况下，腐蚀起始时间和地震脆弱性有相当大的影响。此外，本研究还对劣化过程不同阶段的不确定性进行了系统探索。该练习有助于就地震脆弱性预测的计算复杂性和准确性之间的平衡提供建议。本研究还对恶化过程不同阶段的不确定性进行了系统探索。该练习有助于就地震脆弱性预测的计算复杂性和准确性之间的平衡提供建议。本研究还对恶化过程不同阶段的不确定性进行了系统探索。该练习有助于就地震脆弱性预测的计算复杂性和准确性之间的平衡提供建议。