Estimating the remaining service life of a historical railway bridge

In this paper, the evolution of the railway traffic during the last century is considered in order to estimate the remaining service life of a historical bridge. The selected case-study concerns the El Ourit Bridge designed in 1889 by Gustave Eiffel and located close to the town of Tlemcen, in Algeria. The response of the bridge to train loads is numerically evaluated using a finite element model of the structure. The element most affected by stress variations is identified. The fatigue damage in this element is then quantified by adopting the Palmgren Miner accumulation model. A fully probabilistic approach is adopted by formulating a limit state function based on this criterion and by assuming that the stress amplitude, the fatigue strength, and the damage threshold value play the role of random variables. The obtained results are discussed in order to evaluate the residual service life of the bridge.