Structural assessment of an in-service steel viaduct using time variant reliability analysis

This paper examines corrosion effect on bridges' service life by performing time dependent reliability analysis. Limit state functions are developed based on multiple failure modes, including flexure failure, shear failure and deflection failure. An aging steel viaduct in Australia with span length of 11m is selected for analysis. Section loss rate (22μm/year), load models and viaduct structure capacity is determined based on Australian Standard and in-field data. A time dependent Monte Carlo simulation is then conducted to compute the probability of failure of viaduct due to the three failure modes. This simulation is carried out both for the I-shape girders and girder-deck system. The results elaborate the dominant failure mode and the difference between considering multi failure modes and individual failure mode. Parametric sensitivity analysis is also conducted in the reliability analysis to investigate the level of effectiveness of the factors affecting the viaduct corrosion behaviour.