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<br />
<br />Facts and
<br />Figures
<br />
<br />The Dam
<br />
<br />Where is Hoover Dam?
<br />In Black Canyon on the Colorado River,
<br />about 30 miles southeast of Las Vegas,
<br />Nevada.
<br />
<br />What does the Bou/der Canyon Prqjec/
<br />include?
<br />Hoover Dam and Powerplant and the
<br />All-American Canal in southern Califor-
<br />nia, together with appUllenant structures.
<br />
<br />How high is Hoover Dam?
<br />It is 726.4 fect ti'OIll foundation rock to
<br />the roadway on the crest of the dam. The
<br />towers and Olllamcnts on the parapet rise
<br />40 feet above the crest.
<br />
<br />How much does Hoover Dam weigh?
<br />More than 6,600,000 tons.
<br />
<br />What type of dam is }foOl'a?
<br />A concrete arch-gravity type, in which
<br />the water load is carried by both gravity
<br />action and horizontal arch action.
<br />
<br />Wlwt is the maximum 'rvater pressure at
<br />the ba.\.e of the dam?
<br />45,000 pounds per square foot.
<br />
<br />How much concrete is ill t!le dam?
<br />Three and one-quaI1Cr million cubic
<br />yards. There are 4,360,000 cubic yards
<br />of concrete in the dam. powerplant. and
<br />appurtenant works. This much concrete
<br />would build a monument 100 feet square
<br />and 21f2 miles high; or, if placed on an
<br />ordinary city block. would rise higher
<br />than the Empirc Statc Building (which is
<br />1,250 feet). Or, it would pave a standard
<br />highway. 16 feet wide, from San Fran-
<br />cisco to New York City.
<br />
<br />Sightseers In'hind Hool'cr Dam
<br />
<br />The first concrete for the dam was
<br />placed on June 6, 1933, and the last con-
<br />crete was placed in the dam on May 29,
<br />1935. Approximatcly 160,000 cubic yards
<br />of concrete were placed in the dam per
<br />month. Peak placements were 10,462
<br />cubic yards in one day (including some
<br />concrete placed in the intake towers and
<br />powerplant), and slightly over 275,000
<br />cubic yards in one month.
<br />
<br />How much cement was required?
<br />More than 5 million barrels. The daily
<br />demand during construction of the dam
<br />was from 7,500 to 10,800 barrels.
<br />Reclamation had used only. 5,862,000
<br />barrels in its 27 years of construction
<br />activity preceding June 30, 1932.
<br />
<br />How was chemical heat, caused by setting
<br />cemellt ill the mass structure, dissipated?
<br />By embedding more than 582 miles of
<br />I-inch steel pipe in the concrete. Icewater
<br />circulated through this pipe from a
<br />rcfrigeration plant that could produce
<br />1,000 tons of ice in 24 hours. Cooling
<br />was completed in March 1935.
<br />
<br />What was an unusual feature of Hoover
<br />Dams construction?
<br />The dam was built in blocks or vertical
<br />columns varying in size from about 60
<br />feet square at the upstream face of the
<br />dam to about 25 feet squarc at the
<br />downstream face. Adjacent columns were
<br />locked together by a system of vertical
<br />keys on the radial joints and horizontal
<br />keys on the circumferential joints. Con-
<br />crete placement in anyone block was
<br />limited to 5 feet in 72 hours. After the
<br />concrete was cooled, a cement and water
<br />mixture called grout was forced into the
<br />spaces created between the columns by
<br />the contraction of the cooled concrete to
<br />form a monolithic (one piece) structure,
<br />
<br />What were the principal items of work?
<br />More than 5,500,000 cubic yards of
<br />material were excavated, and another
<br />1,000,000 cubic yards of earth and rock-
<br />fill placed. By feature, this included:
<br />
<br />Excavation-for the diversion tunnels,
<br />1,500,000 cubic yards; for the foundation
<br />of the dam, powerplant, and cofferdams,
<br />1,760,000 cubic yards; for the spillways
<br />and inclined tunnels, 750,000 cubic yards;
<br />for the valve houses and intake towers,
<br />410,000 cubic yards; earth and rock fill
<br />for the cofferdams, 1,000,000 cubic
<br />yards.
<br />Other work items included 4,400,000
<br />cubic yards of concrete placed; 410,000
<br />linear feet of drilling grout and drainage
<br />holes; and 422,000 cubic feet of grout
<br />placed under pressure.
<br />
<br />What were the quantities of principal
<br />materials used in the dam?
<br />Reinforcement steel, 45,000,CXXJ pounds;
<br />gates and valves, 21,670,000 pounds;
<br />plate steel and outlet pipes, 88,000,000
<br />pounds; pipe and fittings, 6,700,000
<br />pounds or 840 miles; structural steel,
<br />18,000,000 pounds; miscellaneous metal
<br />work, 5,300,000 pounds.
<br />
<br />Did the Govemment buy these materials?
<br />Yes.
<br />
<br />What are the geologic conditions at the
<br />damsite?
<br />The foundation and abutments are rock of
<br />volcanic origin geologically called
<br />"andesite breccia," The rock is hard and
<br />very durable.
<br />
<br />What were the excavation depths from the
<br />river:\' low-water surface to foundation
<br />rock?
<br />In the upstream cutoff trench, 139 feet of
<br />material were excavated. The remaining
<br />excavation depths from low-water surface
<br />to foundation rock average 110 to 130
<br />feet.
<br />
<br />43
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