PROJ00077

• Contract/PO #: FS0008X
• Contractor Name: Longmont, City of
• Contract Type: Loan
• Water District: 0
• County: Boulder
• Loan Projects - Doc Type: Feasibility Study

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Table I shows the results of the permeability testing. Estimated per-
meabilities in the concrete ranged from 2,040 to 3,690 feet per year. Falling-
head tests performed on holes B-2 and B-4 both exceeded the capacity of the
pump. Neither hole could be filled at a pumping rate of about 50 gpm. Most of
the water appeared to be flowing out at the rock-concrete contact or at horizon-
tal lift joints.
VII. STABILITY ANALYSIS
General Description
The analysis and repair design were prepared using the Arch Dam Stress
Analysis System (ADSAS) computer program developed by the U.S. Bureau of
Reclamation (1977). The ADSAS program uses the trial load methqd which is one
of the main methods of analyzing arch dams. The program is widely used by the
Bureau and is suitable for analyzing one, two or three centered symmetrical or
non-symmetrical arch dams. The basic input for any dam analysis requires that
the number, location, and the geometrical properties of the arches and can-
tilevers be known. In addition, the program allows input of the following data
for different loading conditions, which include: 1) concrete properties such as
Youngs Modulus, Poisson's Ratio, coefficient of thermal expansion, and unit
weight; 2) rock properties of deformation modulus and Poisson's Ratio; 3) dam
grouting temperatures; 4) concrete temperatures; 5) reservoir water level; 6)
tailwater level; 7) ice loading; 8) silt loading; 9) earthquake loading
(pseudo-static); 10) uplift loading; and 11) grout elevation.
The approach used in this report was to first analyze the existing struc-
ture to determine existing concrete stresses for a variety of loading con-
ditions. Based on the results for the existing dam, an approximate dam con-
figuration after rehabilitation was determined and analyzed for various loading
conditions.

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