Abstract
An advanced theory and its example is shown herein to evaluate the dynamic soil-structure interaction effect for considering the flexibility of the base mat. The displacement and stress of the contact area between structure and soil are treated as unknown functions. Through these unknown functions, the soil which is treated as semi-infinite elastic medium and the structure, of which dynamic characteristics are evaluated by FEM, are combined and coupled analysis is conducted. The dynamic relation of stress and displacement of this contact area can be expressed in the integral form using the Green function and is transformed to matrix form. As an example, response analysis is conducted for a BWR 1100MW reactor building, for a vertical earthquake. The result shows; 1) The rigid body assumption for base mat of the reactor building is not satisfied as indicated by response displacement and acceleration. 2) The distribution of reaction stress is very complicated and so uniform or rigid body stress pattern is not acceptable. 3) The displacement and the stress distribution depend on the characteristics of the structure such as rigidity and mass distribution.
