Forced-Vibration Tests and Numerical Modeling of the Daniel-Johnson Multiple-Arch Dam

Abstract

Forced-vibration tests were conducted on the Daniel-Johnson multiple-arch dam located in northeastern Quebec, Canada. This outstanding structure for its size and complexity is the largest multiple-arch dam in America. The tests aimed to determine the dynamic properties of the dam-reservoir-foundation (DRF) system to be used as a basis for the update of a finite-element model of the system required for further seismic performance assessment. The test procedure is described and the modal properties derived from the recordings are presented together with the extraction procedure, which was particularly complicated because of the coupling of the numerous global and local modes of such a complex structure. Several linear three-dimensional finite-element models were developed to be correlated with the measured dynamic properties. A parametric study on the dam-foundation elasticity was first performed, and the influence of the reservoir water modeling was then extensively studied. The selected model properties resulting from the numerical correlation study enabled reproduction with good accuracy of eight of the measured vibration modes, making the model suitable for seismic analyses.