Identification of priority structures for analysis
Assessment and reduction of seismic risk on existing bridges

The risk associated with bridges, and the consequences of this risk in the event of an earthquake, differ significantly from one structure to another. Some structures, by virtue of their design or typology, or because of their exposure, present an a priori moderate risk in the face of seismic hazard. For others, the question arises as to the profitability of investing in major reinforcement work, in relation to the stakes and losses generated in the event of collapse associated with an event whose probability of occurrence is relatively low.

A vast campaign to systematically and exhaustively bring all existing bridges into line with current regulatory requirements for new structures would, in any case, be unthinkable given :

• the number of structures to be treated ;

• costs incurred by...