Transient analysis of concrete gravity dams by Wavenumber-TD method for general excitation

Abstract

In seismic analysis of concrete gravity dam and reservoir systems using finite-element models, finding an appropriate and simple reservoir upstream truncation condition has been a challenging issue for researchers. The Sommerfeld condition is the classical approach most engineers use for this purpose and it is widely available in commercial finite-element software. In 2012, Wavenumber method was proposed as an alternative approach. The main goal of the present study is to modify this approach so it can handle vertical as well as horizontal ground motions. Moreover, the aim of the study is to evaluate the performance of the approach more thoroughly in comparison to the Sommerfeld truncation boundary, especially for vertical ground motions. With this aim, Pine Flat dam in the USA is used as a typical example. Several models are considered with different values of normalised reservoir length. The dynamic loading considered is the local Taft earthquake record of 1952. Furthermore, two types of reservoir base condition – full reflective and absorptive – are adopted. Overall, this allowed for a thorough examination and evaluation of the effectiveness of the wavenumber-TD approach for seismic analysis of concrete gravity dams.