Interaction of soil and power plants in earthquakes

Bedrock motions are generated from a segment of the Golden Gate record and are applied to a four-layer elastic finite element of a soil site. Three different finite element models are derived to represent a nuclear reactor structure, each reflecting a different degree of refinement. The least refined is a one-dimensional model, having lumped masses, which is rigidly connected to the soil and is subjected to motions found at 45-ft depth in the free field. A second model is identical to the first except that springs are interposed between the base of the one-dimensional model and the soil in order to represent translational and rotational modes of interaction. The most refined of the present models is a two-dimensional, dynamic, elastic finite and element representation of the soil embedded foundation and walls and containment and support stuctures. The results of the various analyses are compared and conclusions are drawn regarding the necessity to include refined model of soil/structure interation in seismic analyses.