A comparison of responses from different seismic soil-structure interaction analyses

Several different horizontal seismic analyses are made of a PWR reactor containment and the resultant responses are compared. The base case is one of the containment sitting on a soil site with a depth of 55 feet to bedrock and 36 feet of backfill surrounding the plant structures. The containment is embedded for about one third of its perimeter. The containment is cylindrical with a height from the top of the basemat to top of the dome of 197.5 feet a diameter of 147.5 feet, and a basemat thickness of 26 feet. The analysis methods are fixed base, frequency-independent impedance function, frequency-dependent impedance function, finite element with backfill and finite element without backfill. The results show that response frequencies are in approximate agreement and that there are notable differences in response amplitudes predicted by the different methods. (orig.)