Seismic‐Induced Slip of Concrete Gravity Dams

The development of an empirical formula for predicting the seismic‐induced slip of concrete gravity dams at the rock interface, often required by the presence of weak rock joints immediately underneath the surface, is presented herein. Based on the “sliding block” concept and the equivalent single‐degree‐of‐freedom system criteria, a series of parametric studies on gravity dams were performed, using a broad seismic data base with simultaneously applied horizontal and vertical ground motion, and reflecting both Eastern North American as well as California‐type conditions. The seismic slip results were statistically processed, using the multiple variables regression technique, in terms of ground‐motion parameters, such as peak acceleration, velocity and displacement, duration and predominant frequency, as well as structural response, such as fundamental frequency of vibration and the lateral acceleration required to cause incipient frictional slip. Since the results compare favorably with existing “sliding block” formulas, such as Richards‐Elms, Newmark, and Wong, the applicability of the proposed seismic slip formula may be extended to earth‐retaining walls and embankments as well.