Service life extension of strategic bridges

This article reports the process that allowed to check the condition of a steel railway bridge having a strategic position within the network. The framework representing the actions needed for the service life extension of the bridge is first described, then the conducted inspections are illustrated, together with the developed numerical analyses and the conception of specific tests on site. The conclusion, downstream of all these analyses and with the comparison of the real-life experiments, was to allow a limited extension of the useful life of the bridge, even with some reductions in the safety factor, respecting a reduction in the speed of railway trains and prescribing continuous monitoring of the bridge. In this context, all the test evaluations, combined with the surveillance/monitoring, and joined with an important numerical modelling activity, lead to the concept of "structural augmentation" of the bridge for service life extension purposes. The specific case of the examined bridge is supposed to be an example of good practice useful for infrastructure authorities.