1. Terminology

Service status

An existing bridge, such as a road bridge, was designed to meet a certain number of needs foreseeable at the time of its design. It therefore has certain characteristics, such as its platform width (roadway and sidewalks), its load-bearing capacity, its resistance to certain accidental stresses... It therefore ensures a certain level of serviceability.

Over time, its constituent materials age, traffic volumes and loads increase, safety requirements evolve, exceptional floods can scour its foundations, etc., with the result that its serviceability diminishes or is no longer adapted to current needs (