The increasingly required maintenance and redevelopment of the architectural and infrastructural heritage have led to the use of structural monitoring and system identification, as useful tools for assessing the state of conservation of the structures and their behaviour, both in operating conditions and in specific conditions, such as in presence of an earthquake. This is fundamental to increase the knowledge of the overall response of the structure and to identify any structural problems. Therefore, the use of monitoring in the study of civil structures is increasing and it involves both existing and new buildings. Thanks to this approach, it is possible to assess the structural reliability allowing higher durability and resistance.