ABSTRACT
Extending the life of historic masonry bridges frequently requires strengthening of arches showing damage or limited load bearing capacity. The “Reinforced Arch Method” (RAM) uses a cable on the extrados and/or the intrados, prestressing the blocks. A recent application is the xv century bridge (Ponte Antico) in Omegna (Verbania, IT) along a route of an historic quarrying district. Originally formed of two stone arches, today a damaged structure with one arch remains after a 20th century collapse. The structure is modelled numerically and assessed in the present condition and with the strengthening by four extrados cables, comparing the results of a linear elastic finite element model and limit state verifications, and static limit analyses with optimization of the thrust line and limit load. The strengthening and the intervention proposed for the collapsed arch are discussed, in relation to their new life as a footbridge on a touristic route.
