Risk assessment of a masonry arch bridge: from on‐site inspections to continuous monitoring

The paper presents an application of a risk‐based methodology – developed as a joint research between Politecnico di Milano and Regione Lombardia – for the prioritization of interventions and the subsequent monitoring of a masonry arch bridge affected by riverbed erosion. Firstly, available data on the regional bridge inventory is evaluated to assign a structural and hydraulic class of attention. Subsequently, onsite inspections and in‐depth documentary analysis were performed, and, finally, a quasi‐static structural and hydraulic monitoring system was installed to detect scour‐induced effects. The monitoring of piers rotation is performed using tiltmeters installed at the skewback of the arches. Environmental parameters, such as temperature, water level and riverbed changes, are also measured to check possible correlation with the monitored rotations. The results from the first two years of monitoring highlight abnormal changes in the rotationtemperature correlation of some piers.