Effects of the structure-soil-structure interaction on the seismic behaviour of a nuclear power plant

We have pointed out the through-the-soil coupling effects on the seismic response of a twin 900 MW PWR resting on an intermediate soil (Vs = 583 m/s). The same study has been performed with a soft soil (Vs = 292 m/s) and we have obtained similar results, but a little more pronounced. We can conclude that the through-the-soil coupling does not sensibly modify the seismic response, such as floor response spectra or differential displacements, of such a nuclear power plant. Thus, it does not seem necessary to take into account the through-the-soil interaction between buildings in the design of a nuclear power plant. (orig./HP)