Structural Stability Evaluation. Sandy Lake Dam.

Abstract : A stability analysis was conducted for a typical interior dam monolith of the Sandy Lake Dam for the following load cases: Normal operation; Normal operation with truck loading (H15-44); Normal operation with earthquake; Normal operation with ice; and 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. 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 concerete 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.