Failure times of deteriorating RC bridges under uncertainty

In this paper, life-cycle probabilistic performance metrics of deteriorating reinforced concrete (RC) structural members are investigated using efficient numerical simulation strategies based on Importance Sampling. The variance reduction technique adopted herein allows to account for the time-variant modeling uncertainties typical of structural analysis of deteriorating systems by efficiently selecting a set of sample structural systems to be analyzed. The proposed approach is applied to evaluate redundancy indicators in terms of failure times with respect to different limit states from damage limitation up to collapse of a RC bridge deck under chloride-induced corrosion. The comparison with crude Monte Carlo simulation techniques highlights the advantages in terms of convergence rate of reference statistics of probabilistic time-variant redundancy indicators. The adoption of efficient sampling strategies can aid the assessment of aging structures, providing more accurate information for optimal planning of preventive and essential maintenance that ensure suitable functionality and safety levels during their entire life-cycle.