A Dynamic investigation of Bouquet Canyon Dam

Abstract

The work reported herein is a part of a comprehensive study of the dynamic response of full-scale structures being conducted under research grant GP-934 of the National Science Foundation. Already reported under this program are dynamic measurements on a nine-story steel frame building and a five-story reinforced concrete building. As a part of this same investigation, static and dynamic tests are under way on a steel frame structure loaded far into the plastic range, so that direct experimental evidence of the behavior of strongly nonlinear hysteretic systems will be available. These experimental studies are all accompanied by complete theoretical investigations with the object of attaining a true understanding of the relationships between analytical calculations and the actual behavior of real structures. An investigation was made of the dynamic properties of an earth dam 200 feet high, by 1200 feet long on the crest, by 1300 feet thick at the base. The dam was excited into steady-state vibrations over the frequency range 1-1/2 to 8 cycles per second by four synchronized rotating eccentric-mass vibration exciters operating on the crest in the upstream -downstream direction. Accelerations were measured on the crest and on the downstream face to indicate the natural frequencies of the dam and to estimate the shapes of the four lowest modes of vibration. The chief results of the investigation are summarized below.