Fatigue Assessment of Old Riveted Railway Bridges: Laboratory Testing of a Real Bridge

Abstract

The bridge over the Quisi Ravine in Alicante Province (Spain), built between 1913 and 1915, consists of six 22-22-42-42-22-22 m long steel Pratt truss spans, the lateral spans being isostatic and the central spans continuous. All the joints between the steel elements are riveted. As the bridge has been carrying railway traffic for more than 100 years, its condition needed to be assessed before carrying out the necessary repairsreinforcement to extend its service life. One of the most interesting tasks on the bridge involved a study of its fatigue behaviour to estimate its remaining useful life. Only a few kilometres away there happened to be another bridge with identical geometry over the Ferrandet Ravine, which had recently been dismantled and taken out of service and had carried the same railway traffic as the one over the Quisi Ravine. Advantage was therefore taken of this unique opportunity to test one of its isostatic spans in order to extrapolate the results to the Quisi Bridge. These tests were carried out at the ICITECH laboratories at the Universitat Politècnica de València in two different scenarios: 1) one test on a 22 m span, and 2) another on one of its girders, in both of which simulated railway traffic cyclical loads were applied. The results allowed us to estimate the number of trains that could pass over the bridge and its remaining service life, and also to define a monitoring method to help in decision making in case of possible failures of its component parts. The study also included an analysis of the bridge's robustness in local failures of some of its elements, which led to a further bridge cyclical loading test with a deliberately damaged component. Even though other researchers had previously carried out fatigue tests on full-scale riveted bridge elements, the ICITECH study is unique in that it is the first time a full-scale bridge has been subjected to fatigue tests. This work was accompanied by advanced numerical modelling studies considering the fracture mechanics theory.