Structures in a nuclear power plant are designed on common or isolated foundations.
The object of this study is to develop an efficient model for prediction of interaction of structures on a common foundation and investigate the influence of the dynamic interaction of N.P.P. structures on a common foundation on the response of structures with various properties such as stiffness and mass of structures, distance between structures, and soil conditions.
Reactor buildings of K.N.U. 9 and 10 are used as the standard structure. The structure is idealized by a stick model and lumped parameter model was used to represent the soil. The L element which is a beam element with a rigid body at an end is implemented to connect the structures with a common foundation to simpify the analysis Dynamic response of structure-soil system is obtained by the direct integration method.
The variance of the mass significantly affected to the structural response, but that of the stiffness did not. In the structure with a common foundation, the maximum displacement approached to that of fixed base as increasing the distance between structures while that of adjacent structures approached to the response of a structure with an isolated foundation. The structure with common foundation turned out not always to be beneficiary compared to the one with an isolated foundation because the structural response with a common foundation is often larger than that with an isolated foundation when the soil condition is harder.
