Reliability assessment and sensitivity analysis of vehicle impacted reinforced concrete circular bridge piers

Abstract

Impact collisions of vehicles with reinforced concrete (RC) bridge piers are an increasingly common event. The collision creates a dynamic effect on the concrete pier not generally considered in design practices, making the piers vulnerable to extensive damage. Not all bridge piers collapse upon impact, and some are kept in service without adequate investigations as to their continued structural viability. Unfortunately, little attention has been provided to investigate the justification of damaged piers kept in service post-impact. A limit state model to identify the probability of failure in the damaged pier is developed and alternative approaches for solving the limit state models are analyzed. In addition, reliability indices and probabilities of failure to quantify damage incurred from vehicular impact are determined. Deterministic analyses do not capture the uncertainties involved in assessing the non-linear dynamic behavior of RC piers under impact loading. To limit the uncertainty associated with determining RC pier’s performance under vehicular impact, sensitivity analyses of the variables controlling impact performance are scrutinized, and a sensitivity ranking to outline the relative importance of the variables to the pier’s performance is developed. The proposed process for determining the reliability of damaged RC piers provides an additional design tool for structural designers, forensic structural engineers, and practitioners for use in analyzing the impact performance of RC bridge piers in a useful, convincing, and economical way.