Dynamic Analysis of Short‐Length Gravity Dams

Abstract

A simplified and economical procedure is developed to analyze the dynamic behavior of short‐length gravity dams. The analysis is based on the Rayleigh‐Ritz method and an idealized dam‐reservoir geometry. The substructure concept is used, in which the dam is modeled as a thick plate and the water in the reservoir is treated as a continuum. The model accounts for dam‐reservoir interaction, water compressibility, and flexibility of the reservoir floor and sides. The natural frequencies and mode shapes of the dam are obtained through a free vibration analysis, and the three‐dimensional effects on these properties are illustrated. A forced vibration analysis is carried out in the frequency domain, and the dam response to all three components of ground motion is obtained. The effects of the length‐to‐height ratio of the dam on its response, and the significance of the cross‐stream component of ground motion are investigated.