Partial factors for reliability-based durability assessment of RC bridges using observational data

Reinforced concrete (RC) bridges in a marine environment deteriorate with time due to chloride-induced corrosion of reinforcing bars. This paper presents a methodology for reliability-based durability assessment of RC bridges in a marine environment. A simple assessment criterion using partial factors that satisfy the target reliability level within the remaining lifetime of existing RC bridges is presented. A procedure to obtain the partial factors updated by the Sequential Monte Carlo Simulation is presented. In this procedure, the chloride concentration distribution by coring test is used as observational data. Partial factors are determined by taking into consideration the reduction in the uncertainty associated with the prediction of chloride-induced corrosion. Therefore, taking into account the reduction in the epistemic uncertainty, the values of the partial factors for durability assessment are different from those used for durability design.