Seismic response of embankment dams: Shear beam analysis vs field observations

Embankment dams are critical elements of infrastructure and perform as a system by integrating various components such as foundation, core, shell, filter and spillway. To analyze their entire response, it is important to properly identify the dynamic characteristics of the overall system based on observations. This paper explores the dynamic response of dams using an analytical shear beam analysis under plane-strain conditions, considering the variation of shear modulus and cross-sectional area with height. The governing differential equation is first solved analytically using Bessel functions, and dynamic response parameters are derived for different natural modes. Transfer functions are then derived from the bedrock to the crest for different variations of shear modulus and levels of material damping. Using these analytical results, the study assesses the applicability of the shear beam analysis to 23 embankment dams in Japan, utilizing decades of recorded acceleration time histories to identify their dynamic response and shear wave profiles with height.