Seismic response of temporary structures Original Research Article

An unanchored temporary structure has five modes of response to base excitation: rest, slide, rock, slide–rock, and free-flight. This paper is concerned with the conditions under which an unanchored object will respond in these modes and, in a rock mode, the maximum amount of tilting and the probability of toppling. The conditions for the five modes of response are derived based on equations of equilibrium and of motion. The rocking response and toppling probability are obtained by the Monte Carlo simulation technique by solving the equations governing rocking response numerically and repeatedly using simulated base motion. Details of the derivation and computation are not presented. Toppling probabilities are given graphically for a number of values specifying dimension of the object.