The Hoover Dam

By

SYED ALMAS ALI

B.TECH,CIVIL ENGG.

VIT UNIVERSITY

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 US states of Arizona and Nevada.

It was constructed between 1931 and 1936 during the Great Depression and was dedicated on September 30, 1935, by President Franklin D. Roosevelt

Construction of the Hoover dam

At the time the dam cost 49$ million to construct.

The dam is 726 feet high, 660 ft thick, and is 1244 ft long.

Hoover Dam required over 3,250,000 cubic yards of concrete plus another million for the power plant, intake towers and other support structures.

With the dam's building complete, in 1935 Hoover Dam became the largest dam in the world.

About the Construction of the Hoover Dam

Geological specialists inspected the volcanic bedrock and found fault lines that were solid enough to support the structure.

Also they sent out surveying parties to make contour maps showing that the area would hold 31 million acre feet of water.

The office engineering staff was busy making system analyses, drawings, specifications, schedules, and cost estimates.

The work on the Dam was finished in the late 1930’s which was six months ahead of the projected time.

ENGINEERING CHALLENGES

DIVERSION TUNNELS

Two 50-foot diameter tunnels drilled into the canyon.

The tunnels diverted the water around the dam while it was being constructed

The tunnels area combined 3 miles in length

The Canyon

The river over millions of years sunk down into the canyon

This created many crevasses and loose rocks, which had to be removed

Building Materials

Use of quick-dry concrete

This called for the concrete to be required to be moved quickly from the production plant to the dam site. .

If it was not moved quickly enough it would set, and had to be scraped out by hand

One of the biggest challenges that the engineers faced in construction of the dam was pouring the concrete. With 4.36 million cubic yards of concrete this became a problem fast. The material used for concrete would create internal heating when mixed with water. The internal heat became a problem, because it would form cracks, which would weaken the structure and cause the curing process to slow down. To resolve the problem the dam was built in a series of interlocking blocks. The blocks were connected by cooling pipes, which cooled the concrete as it was poured into the blocks. The cooling of the concrete did not allow heat to develop and the curing process was able to proceed faster.

Need for the Hoover Dam

The Colorado River was growing out of control Flooding increased rapidly

The surrounding states needed water to support people

• Arizona

• Wyoming

• Colorado

• New Mexico

• Utah

Serving the Public

Electricity

–Supplies 1.3 million people with electricity

Water–Supplies surrounding states with drinking water

Flood Prevention–Prevents floods by holding water back

Disservice to the Public

Releases Methane–Still water causes organic matter to die, releasing methane.

River bed Lowering–The pressure of the still water is digging into the river bed

Destroys Natural ecosystems–Many animals lose their shelters

Water Quality is disturbed

Water Quality

The amount of dissolved oxygen is lowered because the water is still.

The temperature is cooler than the normal river.

River bed Lowering

The river bed is lowering due to the water building up

In 9 years , the water table sank 4 meters.

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