Bridge infrastructures in Europe are facing growing risks induced by the combination of natural and man-induced hazards, ageing, progressive damaging processes as well as the evolution of the type and composition of the traffic loads.

In this context, the structural assessment of the existing structures, with special attention to those closer to the end of the design life, the prioritization of the structural interventions and the optimization of the maintenance schedules become a key issue of the asset management plan.

As such, timely and accurate information from monitoring of structures, integrated with inspection and testing, is crucial to enable appropriate diagnostics to guide cost-effective safety assessments and decisions on repairs, strengthening and renovations.

This paper describes the process of collecting information and assessing structural performance through the data analysis to actively support the maintenance, repair and strengthening activities. A selection of Sacertis case studies on the use of dense sensing on an Italian bridges network of over 50 bridges is hereby presented. Four case studies are detailed where MEMS sensors have been installed based on the specific structural need, with different complexity, with the purpose of monitoring the evolution of deterioration process, supporting a data-informed design of the strengthening intervention as well as providing evidence of the effectiveness of interventions. Both static and dynamic behaviours are analysed as indicators of the structural performance.