PROJ01828

• Contract/PO #: C153749
• Contractor Name: DeWeese-Dye Ditch and Reservoir Company
• Contract Type: Loan
• Water District: 12
• County: Custer
• Loan Projects - Doc Type: Contract Documents

.

";;

Ms. Honey R. Moschetti, President

-6-

December 19, 1994

pounds per cubic foot in the upper portion of the raise section (gage height 34.1 to
gage height 42.1). These values are consistent with previous studies.

6. The potential presence of reinforcing dowels anchored into the original dam were not
considered in the initial analyses. If, for a given load case, initial analyses indicated
that the factor of safety for sliding was less than one or that there was tension in the
concrete at the upstream face, an estimate was made of the anchorage (force) required
to achieve a factor of safety of greater than one or to put the upstream face in
compression. This information was used qualitatively in our evaluation of the stability
and stress analyses results.

Summary of Loading Cases and Evaluation Criteria

A total of six loading cases were analyzed for these evaluations. The loading cases were selected
to represent a range of overtopping depths on the raise section, up to the 50 percent PMF
overtopping condition. A description of the loading cases analyzed and applicable evaluation
criteria are described in the following paragraphs.

Loading Case 1.

Loading Case 2.

Loading Case 3.

Loading Case 4.

94l11\DDREPORT.L 11\

Normal reservoir water surface at the spillway crest, gage height 40.4; with
no flow over the dam crest. Minimum required sliding factor of safety of
3.0. Maximum allowable compressive stress of 333 pounds per square
inch (psi), based on a compressive strength in the lower portion of the
raise section of 1,000 psi and a factor of safety of 3.0.

Reservoir water surface at the dam crest, gage height 42.1; with no flow
over the dam crest. Minimum required sliding factor of safety of 2.0.
Maximum allowable compressive stress of 500 psi, based on a compressive
strength in the lower portion of the raise section of 1,000 psi and a factor
of safety of 2.0.

Maximum reservoir water surface from the 100-year runoff event, gage
height 44.1; with 2 feet of overtopping on the dam crest. Minimum
required sliding factor of safety of 2.0. Maximum allowable compressive
stress of 500 psi, based on a compressive strength in the lower portion of
the raise section of 1,000 psi and a factor of safety of 2.0.

Reservoir water surface at gage height 52.1; with 10 feet of overtopping
on the dam crest. Minimum required sliding factor of safety of 2.0.
Maximum allowable compressive stress of 500 psi, based on a compressive
strength in the lower portion of the raise section of 1,000 psi and a factor
of safety of 2.0.