Fem Model Calibration of Experimental Environmental Vibration Tests on Two Churches Hit by L’Aquila Earthquake

The paper deals with the seismic investigation of two masonry churches, namely Visitazione and San Giuliano, which are located in Poggio Picenze, a small town about 10 km far from L’Aquila. The seismic response assessment of the churches, which were damaged by the severe seismic event occurred in Italy on 2009 April 6th, has been performed by means of experimental dynamic tests and numerical analyses. Firstly, an experimental campaign based on Ambient Vibration Tests (AVTs), which are non-destructive tests especially applied to historical and monumental buildings for evaluating their modal response, has been carried out on the selected constructions in the framework of a cooperation activity between the Ss. Cyril and Methodius University of Skopje and the University of Naples “Federico II”. Such an experimental activity has allowed to obtain the dynamic properties of the examined structures, namely natural frequencies, vibration mode shapes and damping coefficients. The experimental results have been subsequently used to implement a numerical FEM model of the churches in the ABAQUS non-linear analysis software environment. Dynamic linear FEM analyses have been conducted in order to calibrate the experimental results in order to simulate as well as possible the real structural behaviour of inspected churches. Finally, the performed analyses have been of a fundamental importance for both detecting damages into the constructions and programming effective retrofitting interventions.