Reliability profiles for steel girder bridges with regard to corrosion and fatigue

Reliability-based models are developed for time-varying changes in structural performance due to corrosion and fatigue. The fatigue limit state is one of the important considerations in the design of bridges. Accumulated load cycles can cause cracking or even failure. Reliability analysis is performed for the fatigue limit state function of flexure. Prediction of the remaining fatigue life for steel and concrete beams is illustrated on examples of existing bridge girders. Corrosion causes a loss of the section and reduction of the load carrying capacity. The rate of corrosion is a random variable. Three levels of corrosion are considered. Changes in the reliability are evaluated as a function of time, covering the life-time of the bridge.