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|Title:||Structural stability evaluation : Sandy Lake Dam|
|Authors:||United States. Army. Corps of Engineers. St. Paul District.|
Pace, Carl E.
Sandy Lake Dam
Mississippi River headwaters
|Publisher:||Structures Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Miscellaneous paper (U.S. Army Engineer Waterways Experiment Station) ; SL-81-17.|
Abstract: A stability analysis was conducted for a typical interior dam monolith of the Sandy Lake Dam for the following load cases: (1.) Normal operation (2.) Normal operation with truck loading (H15-44) (3.) Normal operation with earthquake (4.) Normal operation witll ice (5.) High-water condition. To obtain a detailed stability analysis of the monolith, the supporting characteristics of the foundation material were determined by in situ testing using a pressuremeter to predict the horizontal strength characteristics of the pile-soil system. Two NX core holes were drilled through typical monoliths to obtain access to the foundation material. The pressuremeter tests were performed and in situ soils data obtained. The horizontal foundation soil modulus was obtained as a variation with depth into the foundation material and with soil deformation for three test positions in each of the two test holes. A conservative horizontal modulus of subgrade reaction was obtained and used in a three-dimensional direct stiffness analysis to determine the forces and deflections at the top of the foundation piles. A beam on an elastic foundation analysis was performed and the pressure, moment, and deflection along the length of the most critically loaded pile were determined. The compressive forces, tensile forces, moments, and deflections predicted for the piles for all load cases were acceptable. However, the shear stresses at the top of the piles were predicted greater than the allowable value. Therefore, 40 kips of strut resistance for each of the interior small piers should be provided to correct this deficiency. The average unconfined compressive strength of the concrete was 5700 psi, which is adequate for this structure. The concrete is well consolidated and uniform in appearance. There is no evidence of alkali-silica or deleterious chemical reaction. The concrete in the interior of the structure appears sound; however, observable deteriorated concrete surfaces should be repaired. After the deteriorated concrete surface is repaired and strut resistance is provided for pier stability, the useful life of the dam will be appreciably lengthened.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Miscellaneous Paper|
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