Non-destructive testing and numerical modelling of a multi-span masonry bridge

The Olla bridge, built in the second half of the 19th century, is an arch bridge consisting of five brick masonry arches with stone masonry piers. The bridge crosses the Stura river along the State Route SS 21, connecting the French border with the South-West part of Piedmont region, and still represents a crucial node for the local commercial traffic. As the structure exhibits diffused surface decay and local damage of the arches, an extensive research program was carried out to assess the structural condition of the historic bridge and is herein summarized. After a discussion on the common issues arising in the structural assessment of historic infrastructures, the Olla bridge is described and full details are given on the different steps of the investigation: (a) historical research, geomatic survey, visual inspection on site and limited local tests on materials; (b) operational modal testing and analysis; (c) development of a FE model based on architectural research and selected modelling assumptions; (d) choice of the uncertain structural parameters and identification of the optimal parameters based on the experimentally obtained data.