Fatigue reliability assessment of a historic railway bridge designed by Gustave Eiffel

The evolution of the railway traffic during the last century is studied as preliminary step towards the estimation of 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. A finite element model of the structure is built and the response of the bridge to train-crossing loads is numerically evaluated with the purpose of identifying the element most affected by stress variations. The Palmgren-Miner accumulation model is used to quantify the fatigue damage in this element. A limit state function based on this criterion is formulated; then, a fully probabilistic approach is adopted 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.