Concurrent modelling of carbonation and chloride-induced deterioration and uncertainty treatment in aging bridge fragility assessment: Fid-Bau Portal

Concurrent modelling of carbonation and chloride-induced deterioration and uncertainty treatment in aging bridge fragility assessment

Mortagi, Mohamed / Ghosh, Jayadipta

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.