Damage assessment of a cloister vault

Vibration-based damage identification methods are fundamental tools for the condition assessment of historical constructions prone to earthquakes. However, despite the substantial advances in the field, several issues must still be deepened to broaden the application range of such tools and to assert their effectiveness. This is particularly true for the vaulted systems considering their modal characteristics. This study deals with the damage detection of a cloister vault of the Middle Age castle sited in Bussi sul Tirino (Abruzzo, Italy), an area of moderate seismicity, which was significantly damaged by an earthquake in 2009. Due to the impossibility to have experimental measures related to the non-damaged initial state, an a priori numerical model of the undamaged vault is set up using the geometrical and mechanical properties measured on site. Ambient noise measurements were then carried out to identify the dynamic behaviour of the cloister vault in the current situation, where seismic damage is present. The a priori model is then updated on the basis of the modal parameters identified by the ambient noise measurements. The differences between the a priori and updated models are analysed to identify the presence of damage. The results found allow for discriminating the real structural damage suffered by the vault.