A dam is a barrier that impounds water and creates reservoirs. Dams suppress floods and provide water for uses like irrigation, power, and navigation. The Hoover Dam is a concrete arch-gravity dam on the Colorado River between Nevada and Arizona. It was constructed between 1931-1936 to control floods and generate hydroelectric power. Over 4 million cubic yards of concrete were used to build the dam, which stands 726 feet tall and created Lake Mead. The dam continues to provide flood control and power to millions in the Southwest United States.

2. What is DAM?
A dam is a barrier that impounds water or
underground streams. Reservoirs created by
dams not only suppress floods but also provide
water for activities such as irrigation, human
consumption, industrial use, aquaculture,
and navigability. Hydropower is often used in
conjunction with dams to generate electricity

3. TYPES OF DAMS:
Dams can be grouped according to the type of material of which
they are constructed as follows;
CONCRETE DAMS:
 Concrete dams are further grouped according to how they
achieve their strength and stability.
 Concrete Gravity Dams
 Concrete Arch Dams
 Concrete Buttress Dams
FILL (EMBANKMENT) DAMS:
 Earth Dams
 Earth and Rock Fill Dams
 Concrete Faced Rock Fill Dams

4. HOOVER DAM
•The Hoover Dam, once known
as Boulder Dam, is a concrete arch-
gravity dam in the Black Canyon of
the Colorado River, on the border
between the U.S. states
of Nevada and Arizona
•The main purpose was to prevent the
turbulent Colorado River from flooding
•Hoover Dam still stands as a world-
renowned structure.
•The Dam is a National Historic
Landmark and has been rated by the
American Society of Civil Engineers as
one of America's Seven Modern Civil
Engineering Wonders.

5. DAM DATA
 Impounds Colorado River
 Type= Concrete gravity arch type
 Construction began= 1931
 Purpose= Power, flood control, storage
 Opening date= 1936
 Construction cost= $49 million (1931)
 Height= 726.4 ft (221.4 m)
 Length= 1,244 ft (379 m)
 Elevation at crest= 1,232 ft (376 m)
 Width (crest)= 45 ft (14 m)
 Width (crest base)= 660 ft (200 m)
 Dam volume= 3,250,000 cu yd
 Catchment area= 435,000 km2

6. ARCHITECTURAL PLAN

7. SECTIONAL ELEVATION

8. CONTRACTING
 On January 10, 1931, the Bureau made the bid
documents available to interested parties, at five
dollars a copy. The Bureau officials eventually
decided on a massive concrete arch-gravity dam, the
design of which was overseen by the Bureau's chief
design engineer John L. Savage.
 Bid was won by Six Companies, Inc.
 The monolithic dam would be thick at the bottom and
thin near the top, and would present a convex face
towards the water above the dam. The curving arch
of the dam would transmit the water's force into the
abutments

9. CONSTRUCTION
 8.5 million pounds of dynamite was used to blast the Canyon to
construct the foundation for the dam
 4.4 million cubic yards of concrete
 88 million pounds of plate steel and outlet pipes
 6.7 million pounds of pipe and fittings
 45 million pounds of reinforced steel
 50,000 tools and machines were used during construction
 To make the concrete durable, strong and increasing its overall
performance, the engineers specified a new innovation in concrete
admixtures: Pozzolith water-reducing admixtures
1. Labour force
2. Ground works and rock clearance
3. River diversion
4. Concreting

10. RIVER DIVERSION
 Four diversion tunnels were driven through the canyon
walls, two on the Nevada side and two on
the Arizona side. These tunnels were 56 ft (17 m) in
diameter. Their combined length was nearly 16,000 ft, or
more than 3 miles (5 km).
 First the base, or invert, was poured. Gantry cranes,
running on rails through the entire length of each tunnel
were used to place the concrete. The sidewalls were
poured next.
 Movable sections of steel forms were used for the
sidewalls. Finally, using pneumatic guns, the overheads
were filled in. The concrete lining is 3 feet (1 m) thick,
reducing the finished tunnel diameter to 50 ft (15 m).The
river was diverted into the two Arizona tunnels on
November 13, 1932; the Nevada tunnels were kept in
reserve for high water

11. RIVER DIVERSION PLAN

12. CONCRETING
 Concrete heats and contracts as it cures, the
potential for uneven cooling and contraction of
the concrete posed a serious problem
 Engineers calculated that if the dam was built in
a single continuous pour, the concrete would take
125 years to cool, and the resulting stresses
would cause the dam to crack and crumble.
Instead, the ground where the dam would rise
was marked with rectangles, and concrete blocks
in columns were poured, some as large as 50 ft
square (15 m) and 5 feet (1.5 m) high

13. Contd.
 Each five-foot form contained a series of 1-inch
(25 mm) steel pipes; cool river water would be
poured through the pipes, followed by ice-cold
water from a refrigeration plant.
 When an individual block had cured and had
stopped contracting, the pipes were filled
with grout.
 Grout was also used to fill the hairline spaces
between columns, which were grooved to
increase the strength of the joints.

14. RECTANGULAR
BLOCKS
ARRANGEMENT

15. SPILLWAY
 The dam is protected against over-topping by
two spillways. The spillway entrances are
located behind each dam abutment, running
roughly parallel to the canyon walls.
 The spillways were modified in 1947 by adding
flip buckets, which both slow the water and
decrease the spillway's effective capacity, in an
attempt to eliminate conditions thought to have
contributed to the 1941 damage of cavitations

16. Water enters the Arizona spillway (left)
during the 1983 floods. Lake Mead water
level was 1,225.6 ft (373.6 m)

17. ROADWAYS AND
TOURISM
 Nearly 100 million people tour the dam each
year
 The Hoover Dam, and the newly constructed
Hoover Bypass, or Mike O'Callaghan – Pat
Tillman Memorial Bridge, is engineering
marvels that shows American integrity and
power. They stand out as monuments of
determination and exemplify how technology
contribute to engineering success

18. The Hoover Dam, and the newly
constructed Hoover Bypass, or Mike
O'Callaghan – Pat Tillman Memorial Bridge

19. CONSTRUCTION DEATHS
Oskar Hansen's memorial which reads-
”They died to make the desert Bloom”

20. DEDICATION AND
COMPLETION
A formal dedication ceremony was held
in September 30, 1935 in which the
structure was dedicated by then
President Franklin D. Roosevelt

21. Other Facts.
 Nearly 100 million people tour the dam each year
 Lake Mead’s water is enough to flood the whole New
York city
 Concrete used was enough to pave 2 lane roads from
San-Francisco and New York
 By its completion in 1935, the Hoover Dam was the
greatest concrete project ever recorded, using more
masonry than the Great Pyramid at Giza (4.5 million cu
yd)
 Equal to the amount needed to build a two-lane highway
from Seattle to Miami, or a 4-ft-wide sidewalk around the
Equator
 It remains as the highest dam in the Western
Hemisphere

22. PHOTO GALLERY

24. REFERENCES
 Official website of Hoover Dam
 Historic Construction Company Project – Hoover Dam
 Frank Crowe – Builder of Hoover Dam
 The Hoover Dam – A Nat -GEO Documentary
 The Majesty of Hoover Dam by David Rogers, Ph.D.,
P.E., R.G, C.E.G., C.HG, M.ASCE

25. THANK YOU