Seismic Response of Unanchored Bodies

This paper is concerned with the response of a rigid body subjected to base excitation. Using analytical and numerical methods of investigation, the results are presented in a series of graphs giving (1) the criteria for initiation of various modes (rest, slide, rock and slide‐rock) of response and, using an ensemble of 75 real earthquake acceleration records, (2) the mean plus standard deviation of the distance of sliding relative to the base and (3) the probability of overturning during rocking. Based on the results in (3), two tables are prepared which give, corresponding to probability of overturning equal to 0.16 and 0.5, allowable peak base acceleration.