Abstract: Based on records of the near-fault strong earthquake of the typical slip fault in the world, the effects of hanging wall / foot wall on a seismic design spectrum of a nuclear power plant is analyzed, and a reference is provided, it is for constructing the design spectrum of the nuclear power plant which counts in effects of hanging wall / foot wall of the near-fault is provided. Based on the near fault records of distinct areas of the hanging wall / foot wall, values of control parameters AD/V² and V/A for the peak ground motion ratio in Newmark method are analyzed. It is found that a inflexion period of seismic design spectrum of the nuclear power plant changes with characteristics of strong earthquake records, and the values of AD/V² and V/A are affected by the hanging wall / foot wall effect. The V/A value associated with the hanging wall is smaller than that in other areas, while theAD/V² value is bigger than that in other areas. Since the values of AD/V² and V/A determine periods of the third and fourth control point of the designed spectrum, the shape of the designed spectrum is also affected. By comparing the determined design spectrum with RG1.60 design spectrum, it is found that the hanging wall / foot wall effect has a significant impact on the spectral values within the short period of the designed spectrum, which makes the spectral values within the short period increase,while the impact on the medium / long period is not evident. Whether either the shape or the values of the designed spectrum, the change of the designed spectrum of the bedrock site is greater than that of design spectrum of soil site. It can be seen therefore that the influence of the hanging wall / foot wall effect should be taken into account in future preparation of standard response spectrum.

Key words: near-fault strong motion, the hanging wall/foot wall effect, seismic design spectrum of NPP, Newmark method