Probabilistic method for estimating remaining fatigue life in steel bridges using measured strain data

Abstract

Transportation officials face the difficult task of maintaining the nation’s inventory of bridges under the pressure of reduced budgets and an aging infrastructure. To prioritize the inspection, rehabilitation, or replacement schedules for each bridge, quantitative data are often needed to distinguish between bridges in an inventory. Measured strain data can be used to estimate the remaining fatigue life of fatigue-sensitive connections and provide quantitative data to bridge owners. Deterministic approaches have previously been developed and presented in design codes. However, due to the inherent scatter of fatigue data, a probabilistic approach may be more appropriate means of calculation. The probabilistic method allows a bridge owner to weigh the risk of maintaining a bridge past its design service life. A probabilistic approach to calculating the remaining fatigue life is discussed in this paper and applied to a fracture-critical bridge.