SEISMIC VULNERABILITY AND RETROFIT METHODOLOGIES IN MEDIUM-LENGTH REINFORCED CONCRETE BRIDGES

An important number of short and medium span bridges in the world were built before 1970. Particularly, in Mexico, the typical structural configuration of these bridges is a simple supported concrete deck on reinforced concrete beams, for two lane roads. Just a few of them have been designed for seismic actions and during their life several increments of the live load amplitudes have been presented. This paper comments the most common procedures to assess the seismic vulnerability of these structures and the techniques used to rehabilitate and retrofit them. Special emphasis is devoted to the importance of the substructure type on the expected damage limit states of the bridges.