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|Title:||Vibration test of Richard B. Russell Concrete Dam before reservoir impoundment|
|Authors:||United States. Army. Corps of Engineers. Savannah District.|
Chiarito, Vincent P.
Mlakar, Paul F.
Vibration response tests
Richard B. Russell Dam
|Publisher:||Structures Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Technical report (U.S. Army Engineer Waterways Experiment Station) ; SL-83-2.|
Abstract: This forced vibration test of Richard B. Russell Dam was conducted before an appreciable reservoir is impounded. Hence a rare opportunity was seized to experimentally measure the dynamic properties of a concrete gravity dam without hydrodynamic interaction. Richard B. Russell Dam has recently been built by the Corps of Engineers approximately 170 miles from the mouth of the Savannah River between the States of Georgia and South Carolina. The crest of the concrete gravity part of the dam is 1884 feet long and is composed of 13 nonoverflow, 8 intake, and 11 spillway monoliths, the tallest of which is approximately 200 feet high. In conjunction with a second test, planned after reservoir impoundment in 1984, an experimental measure of prototype hydrodynamic interaction will also be obtained. The structure was excited at three locations by a crest mounted 17,000-pound inertial mass which was driven by an electrohydraulic servo-controlled actuator. The force input to the dam was computed as the product of the measured acceleration and the 17,000-pound mass. Servo accelerometers with a sensitivity of 0.25 volts/g measured the horizontal crest accelerations of the tallest 31 monoliths and the distribution of horizontal acceleration with elevation in the three drive point monoliths. All tests were 1/2 decade/minute sine sweeps from 25 to 1 Hz. Analog signals were recorded on magnetic tapes and later digitized and processed by a Structural Dynamics Analyzer. The results reveal the linear and the nonlinear characteristics of the complex structure. The natural frequencies and mode shapes are consistent with the results of two- and three-dimensional finite element analyses when foundation flexibility is considered. Modal damping ratios were greater than independently measured concrete specimen values but were scattered between 1.4 and 5.2 percent. Relative joint motion was observed above a low response threshold.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Technical Report|
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