HISTORICAL REINFORCED CONCRETE ARCH BRIDGES OF SONGAVAZZO AND BRIVIO (ITALY): DYNAMIC IDENTIFICATION AND SEISMIC VULNERABILITY ASSESSMENT

The problem of seismic safety assessment is discussed with reference to the case of an histor ical reinforced concre te bridge; specifically,a bridge located inSongavazzo, Jtalyacrossthe Valeggia river, completed in 1911. Experimental testing has been performed, providing ali the required information for the identification ofthedynamicbehaviour. Seismic vulnerability has been evaluated with both response spectrum moda! analyses and nonlinear static (push -over) analyses as ,veli. The bridge response is compared to the one obtained for a similar bridge yet reflecting a different structural scheme. Structural analyses have allowed to high light different structural concepts while, on the other hand, they show the complementary nature of the two bridges. In both cases, reinforced concrete arches are mainly subjected 10 axial Joads a n d prov ide t he main struc tural system