Lesson learned after the Emilia-Romagna, Italy, 20–29 May 2012 earthquakes: A limit analysis insight on three masonry churches

Three masonry churches collapsed or severely injured during the 20–29 May 2012 earthquakes occurred in Emilia-Romagna, Italy are analyzed in detail from a numerical standpoint. A recently presented standalone 3D limit analysis code is utilized to evaluate failure mechanisms and horizontal acceleration causing the collapse. A comparison with the recent Italian Guidelines devoted to the safety assessment of monumental buildings is also provided. The horizontal acceleration associated to the first active failure mechanism is compared with that actually active during the 20–29 May shakes. A preliminary modal analysis is also conducted to evaluate vibration modes, to compare the numerical limit analysis acceleration with the spectral acceleration kept by the structures.