Operational Modal Analysis and Structural Identification of a Masonry Arch Bridge

In the last two decades, Operational Modal Analysis (OMA) has emerged as a fully Non-Destructive testing methodology to investigate the global state of buildings and structures. This is particularly appealing in the case of existing constructions for which destructive testing may be difficult or even impossible, as it is the case of historical and artistical heritage. In this paper, OMA is applied to an existing masonry bridge. Multi-setup frequency-domain technique is applied to estimate dynamic characteristics of the bridge, while multi-objective optimisation based on frequencies and modal shapes eventually allows for the estimation of a number of mechanical features (materials and boundary conditions) of an appropriate numerical model. The results provide interesting insights on the identifiability of the structural model, highlighting the potential of the methodology along with critical issues which must be properly taken into account in the assessment of the results.