FEM Calibration of Masonry Towers in Historic Centers: A Case Study: Fid-Bau Portal

FEM Calibration of Masonry Towers in Historic Centers: A Case Study

Buzzetti, Martina / Acito, Maurizio

Historical centers of many European countries are characterized by masonry buildings clustered in aggregates. It is not rare to find towers or bell towers embedded in the urban tissue. Their behavior is difficult to interpret and correctly model, which is fundamental to assessing their seismic vulnerability and identifying possible effective retrofitting interventions. In the literature, many attempts to solve this issue have been made. However, the interaction among adjacent buildings is still an open issue. Since the structural behavior is strongly influenced by surrounding buildings, the constraints assumed in numerical models may affect numerical results in a significant way. Nowadays to overcome this issue, operational modal analysis (OMA) is used to identify the dynamic structural properties and correctly calibrate numerical models. In this work, the tallest historical tower in Mantua (northern Italy), named Gabbia Tower, is studied. The FE model, developed in the commercial software Abaqus CAE, of this confined tower is semi-automatically calibrated through the commercial software Isight Design Gateway, based on experimental results coming from OMA. By changing the material properties and the constraints, the differences between the numerical and experimental natural frequencies and mode shapes are minimized. During the calibration, it is evident the challenge in modeling the interaction among surrounding buildings. Indeed, mode shapes can be completely different depending on the constraints assumed. This work tries to emphasize the problem of modeling the interaction between adjacent buildings and to propose a quite simple method for semi-automatized model calibration using available commercial software.