Evaluating the Seismic Capacity of an Existing Maillart-Arch-Type Bridge: Case Study of Viadotto Olivieri

This paper deals with the seismic assessment of an existing Maillart-arch-type bridge. The evaluations concern a still-in-use deck-stiffened concrete arch bridge, the Viadotto Olivieri (Salerno, South Italy): it’s an r.c. deck-arch bridge having a permanent-to-live loads ratio of 6:1. The seismic characterization has been supported by various FEM models. Multiple accurate analyses have been necessary to exploit effectively the potentials of this structural scheme before evaluating any possible retrofit strategies. With this aim, different schemes were checked, changing deck configurations and restraints at the base. The bridge has been modeled in a realistic way, using shells and beams. A preliminary linear analysis has been performed that consisted of applying a total horizontal force equal to 10% of the bridge’s permanent loads in both plan directions. This displayed the most vulnerable elements, which were later also confirmed by modal outputs. The response spectrum analysis, assuming the seismic parameters of the site, showed that the highest effects occur for translational local modes in which only a few macro-elements are involved (monolithic behavior). The results also demonstrate the good performance of the Maillart-arch scheme in counteracting seismic loads.