Reliability assessment of a continuous bridge beam with exposed reinforcement

Bridges are not only subjected to service loads, but also to severe environmental conditions. Over time traffic tends to increase, and yet the structural resistance tends to decrease due to ageing. This article presents a study of the behaviour of a continuous reinforced concrete bridge with various levels of exposed reinforcement designed in accordance with Canadian codes. For the purposes of this study, reinforcement exposure was varied incrementally from zero (as-designed) to 63% of the span length. Different scenarios were considered for the possibility of exposure at the top, bottom or both faces of the concrete girders. The probability of failure and the corresponding reliability index were calculated for each scenario with Monte Carlo simulations using deterioration coefficients from experimental testing and published results of beams with exposed reinforcement. Over the range of steel reinforcement exposures, the reliability index changed from 3.14 to 2.81 and the probability of failure changed from 1.6 x 10(-3) to 4.4 x 10(-3).

Automated summary

This article presents a study on the behavior of a continuous reinforced concrete bridge with varying levels of exposed reinforcement. The probability of failure and reliability index were calculated using Monte Carlo simulations for different exposure scenarios.