Rocking Compliance Functions for Rigid Bases Allowed to Uplift

Abstract

In the earthquake‐resistant design of structures such as nuclear power plants and above‐ground tanks, consideration is given to the effect of base uplift on the response of these structures. This paper presents an iterative procedure for analyzing the rocking response of a rigid base allowed to uplift. The base is placed on an elastic half‐space and is subjected to a gravitational force and an overturning moment. The proposed method is applied first to a rectangular base under static loading conditions, and the results are compared with those of a conventional method. Then, the method is applied to the problem of dynamic loading conditions. The effects of lift‐off on the real and imaginary parts of the rocking compliance are examined. A large increase is produced in the real part. However, the imaginary part is only slightly increased by the effect of uplift. Further, the dynamic effect on the minimum contact area of the base is negligible.