Determining and Tuning Models of a Masonry Bridge for Structural Assessment

The paper describes a procedure aimed at developing FE models suitable to the seismic assessment of masonry viaducts. The modeling strategy is based on architectural research, non-destructive or minor-destructive tests, operational modal testing and surrogate-based model updating. In more details, the adopted methodology involves the following steps: (i) preliminary investigations including historical research, geomatic survey and local tests on materials; (ii) operational modal testing and analysis; (iii) FE modeling based on the available geometry and selected assumptions; (iv) choice of the uncertain structural parameters of the FE model; (v) identification of the optimal parameters by minimizing the difference between the model responses and the experimental responses using surrogate models. The 19th-century Olla bridge (Gaiola, Italy) is used to exemplify the proposed approach. The investigated structure turns out to be of special interest because the use of a limited number of sensors allows the identification of a relatively large number of normal modes. Consequently, the installation of a dynamic monitoring system on the bridge has been scheduled.