New Sliding Bearing Technique Used in the Construction of Nuclear Power Plants: Aseismic Bearings.

The construction of a nuclear power plant requires a thorough analysis of the seismic conditions, particularly in the region of the proposed site. In the case of a nuclear power plant there are very few regions in the world where the risk of seismic disturbances can be considered negligible. In order to overcome this difficulty and to be able to construct power plants which are adequately secure with regard to seismic disturbances, Electricite de France and SPIE Batignolles have developed a foundation system for a power plant on sliding bearings which permits standard construction in zones of strong seismic disturbance. Hence standard buildings and machinery can be used which were developed for zones of low seismic disturbance. With this type of bearing, the horizontal earthquake accelerations of the structure cause a distorsion of an elastomer block; then, if the horizontal forces exceed a certain value, a sliding action between friction plates takes place, which makes it possible to limit the accelerations in the structure and to make them independent of the level of seismic disturbance.