Ambient vibration test and numerical investigation on the St. Giuliano church in Poggio Picenze (L’aquila, Italy)

Abstract

The paper deals with the investigation of the seismic behaviour of a masonry church sited in Poggio Picenze (district of L’Aquila) and damaged by the L’Aquila seismic event occurred in Italy on 2009 April 6th. This earthquake, classified as an exceptional event, caused significant damages to about 15,000 buildings. Above all, many of the cultural sites of L’Aquila and the surrounding villages, including churches, palaces and other monuments dating from the Middle Ages and Renaissance, were harmed in a severe way or demolished. The current work is framed in the post-seismic scenario of Poggio Picenze, a small town located about 10 km to the South-East of L’Aquila, and it is aimed at the seismic response assessment of the St. Giuliano church by means of experimental dynamic testing and numerical analyses. Firstly, an experimental campaign based on Ambient Vibration Tests (AVTs), that are non-destructive tests especially applied to historical and monumental buildings for evaluating their modal response, has been performed on the selected construction in the framework of the COST C26 Action as a cooperation activity between the Ss. Cyril and Methodius University of Skopje and the University of Naples “Federico II”. As a result, the method has allowed to obtain the dynamic properties of the examined structure, namely natural frequencies, vibration mode shapes and damping coefficients. The experimental results have been subsequently used to implement a numerical FEM model of the church in the ABAQUS non linear code environment. Linear FEM analysis has been carried out to calibrate the experimental results and a suitable investigation in the nonlinear field has been conducted to predict the post-seismic structural behaviour of the church. Finally, the performed analyses have been of a fundamental importance for both detecting damages into the construction and programming effective retrofitting interventions.