Site effects of the Denis-Perron dam (SM-3): A case study in Eastern North America

Abstract

Eastern North America (ENA) is part of a region with low-to-moderate seismicity; nonetheless, some significant seismic events have occurred in the last few decades. Recent events have reemphasized the need to review ENA seismicity and ground motion models, along with continually reevaluating and updating procedures related to the seismic safety assessment of hydroelectric infrastructures, particularly large dams in Québec. Furthermore, recent researchers have shown that site-specific characteristics, topography, and valley shapes may significantly aggravate the severity of ground motions. To the best of our knowledge, very few instrumental data from actual earthquakes have been published for examining the site effects of hydroelectric dam structures located in eastern Canada. This article presents an analysis of three small earthquakes that occurred in 1999 and 2002 at the Denis-Perron (SM-3) dam. This dam, the highest in Québec, is a rockfill embankment structure with a height of 171 m and a length of 378 m; it is located in a narrow valley. The ground motion datasets of these earthquakes include the bedrock and dam crest three-component accelerometer recordings. Ground motions are analyzed both in the time and frequency domains. The spectral ratios and transfer functions obtained from these small earthquakes provide new insights into the directionality of resonant frequencies, vibration modes, and site effects for the Denis-Perron dam. The crest amplifications observed for this dam are also compared with previously published data for large dams. New statistical relationships are proposed to establish dam crest amplification on the basis of the peak ground acceleration (PGA) at the foundation.

Spatial Analysis of Vibration Frequency Distribution of Jatibarang Dam Semarang Using Raspberryshake 4D

“…In the results of the dominant frequency (f 0 ) obtained by Koen (2014) at Jatibarang Dam is between 2.4 -6 Hz and there are differences in the value of the dominant frequency, this can occur because according to Verret (2021) in the type of urugan dam it is recommended to use an accelerometer with a frequency of 50 Hz and above using a low pass filter. In Appendix B, the distribution of the dominant frequency contour (f 0 ) and the amplification value obtained at the research point can be seen.…”