Vulnerability assessment methods for rocking and overturning of free standing elements

This paper presents a comparison between different methods for assessing the probability of rocking and overturning of free standing elements, under the action of ground motions of given intensities. The classical Ishiyama criterion is considered and compared with both kinematic linear and non linear analyses recommended by the Italian Standard (i.e. KL and KNL respectively) and with the displacement based approach proposed by Lam-Gad. The main differences among these methods are highlighted and validated on the basis of experimental tests available in literature, by using real seismic records. Then, the different stability criteria are used to obtain overturning stability charts, based on conventional spectra assumed by Eurocode 8 and some considerations concerning the applicability conditions of each method are given.