Influence of calculation conditions on reactor building vibration due to aircraft impact load

The purpose of this study is to investigate the influence of calculation conditions, such as damping and the boundary conditions between a reactor building and soil, on reactor building vibration due to aircraft impact load. In this study, we created a 3D finite element building model and applied a load-time function for military aircraft. Transient vibrations were analyzed under several calculation conditions. We compared the maximum floor acceleration distributions calculated with and without damping and examined the influence of damping on the acceleration distributions. The calculation results without damping seemed to show an unrealistic distribution; therefore, damping is indispensable for assessing the building vibration. The influence of the boundary condition was examined by varying the support condition of the building. A boundary condition in which the displacement perpendicular to the building walls under the ground was fixed led to underestimation of the acceleration of the first floor; therefore, the fixed condition of the wall should not be applied to the model. Comparison between three spring support conditions (soft, medium, and hard) showed that the maximum accelerations were in almost complete agreement. This indicates that the influence of the spring constants of the soil-structure interaction on a reactor building is small. (author)