Assessment of a historical railway bridge toward traffic regulationrequirements

Not far away from the Algerian town of Tlemcen, an arch bridge was built, in 1889, with the purpose of enabling the railway link to cross a rather sharp mountain area. The structure was named the El Ourit bridge, and its design was conceived by the world-famous French engineer Gustave Eiffel. The bridge is now 123 years old and it is demanded to satisfy the present safety requirements, resulting from new train traffic features and from the updated seismic code. The different components of the bridge were deeply inspected by a geometric, topographic and pathological survey. Specimens of wrought iron were tested in the laboratory to characterize the behavior of the bridge constitutive material,. A finite element model of the bridge was then created on the basis of its actual geometry. A historical ground motion record was used to carry out the dynamic analysis. The structural safety was checked with reference to the last version of the Algerian seismic code. It was possible to conclude that the original design is consistent even with the seismic hazard update.