Effect of ground motion frequency content on nuclear power plants including soil-structure interaction

The study presented in this paper examines the impact of earthquakes with different frequency content on containment nuclear structures. Three sets of strong ground motion records (i.e., nine ground motions in total) were analyzed with low, medium and high Acceleration/Velocity ratio. The selected earthquakes all fall in the west coast of North America Region. Comparison with the design spectra for the west coast given in the US-NUREG (2001) has shown that the average spectrum of the nine selected earthquakes is in good agreement with the WUS design spectrum. Two cases of the foundation have been considered namely, fixed case and flexible case. In the flexible case the soil-structure interaction is considered rock and clay (i.e., firm to stiff clay soil) soil profiles. The effect of all earthquakes on the structure responses has been examined in the two foundation cases. The results show that there is correlation among the earthquakes with different A/V ratio and the estimated responses. Additionally, the soil structure interaction has significant impact on the responses, and it increases with increasing the design ground motion intensity.