1. Equipment, support devices and protective elements

A bridge is first and foremost intended to provide a service with a level of safety normally accepted by society. The bridge's equipment, supports and protective elements play a major role in ensuring the required level, enabling users to cross an obstacle without any risks other than those associated with their own behavior. Can you imagine using a road bridge without a wearing course, lateral restraint systems or expansion joints? The cost of equipment usually represents 8 to 12% of the total initial cost of a bridge, and in certain extreme cases can reach 25 to 30%. But the cost of maintenance represents a much higher fraction of the overall funds allocated to the maintenance of engineering structures by the State or local authorities.

It makes little sense to talk about the pathology of equipment: its lifespan cannot be compared to that of the supporting structure,...