16th International Conference on Structural Mechanics in Reactor Technology, Washington, United States Of America, 12 - 17 August 2001, pp.1-8
The rocking response of rigid bodies with rectangular footprint, freely standing on a horizontal rigid plane is studied analytically. Rigid bodies are subjected to simulated single component of horizontal earthquake time histories. The effect of the baseline correction, applied to simulated excitations, on the rocking response is first examined. The sensitiveness of rocking motion to the details of simulated earthquakes and the geometric properties of rigid bodies (i.e., slenderness ratio and size parameter) is investigated. Because of the demonstrated sensitivity of rocking response of rigid bodies to these factors, prediction of rocking stability must be made in the framework of probability theory. Therefore, using a large number of simulated earthquakes, the effects of duration and shape of intensity function of simulated earthquakes on the overturning probability of rigid bodies are next studied. In the case when a rigid body is placed on any floor of a building, the corresponding overturning probability is compared to that of a body placed on the ground. For this purpose, several shear frames with fundamental natural period of vibration ranging from 0.5 see (stiff) to 2.0 sec (flexible) are employed. Finally, the viability of the energy balance equation, which was introduced by Housner in 1963 and widely used by the nuclear power industry to estimate the rocking stability of rigid bodies, is evaluated. It is found that the energy balance equation is robust. This paper also gives examples to show how this equation can be used.