Damaging behavior of masonry arch bridges: analysis of 'Ponte delle Torri' in Spoleto, Italy

Damage effects on the dynamic response of the masonry bridge 'Ponte delle Torri' in Spoleto are investigated. To model ancient masonry material response, a scalar damage variable is introduced in the stress-strain law, whose evolution is driven by a nonlocal strain measure. A 3D finite element formulation is used. Bridge natural frequencies and modal shapes are evaluated and compared with experimental results. Then, the nonlinear step-by-step dynamic analysis of the entire bridge and an equivalent pier is performed, considering a set of natural earthquakes. The response of the bridge is analyzed in terms of top displacement, acceleration and damage patterns.