Bridge at
Hoover Dam
THE WIDER VIEW: Taking shape, the
new bridge at the Hoover Dam
Creeping
closer inch by inch, 900 feet above the mighty Colorado River, the two
sides of a $160 million bridge at the Hoover Dam slowly take shape.
The bridge will
carry a new section of US Route 93 past the bottleneck
of the old road which can be seen twisting and winding around and
across the dam itself.
When
complete, it will provide a new link between the states of Nevada and
Arizona . In an incredible feat of engineering, the road will
be
supported on the two massive concrete arches which jut out of the rock
face.
The arches are
made up of 53 individual sections each 24 feet long
which have been cast on-site and are being lifted into place using an
improvised high-wire crane strung between temporary steel pylons.
The arches
will eventually measure
more than 1,000 feet across. At the moment, the structure
looks like a
traditional suspension bridge.. But once the arches are
complete, the suspending cables on each side will be removed.
Extra vertical columns will then be installed on the arches
to carry the road.
The
bridge has become known as the Hoover Dam bypass, although it is
officially called the Mike O'Callaghan-Pat Tillman Memorial Bridge,
after a former governor of Nevada and an American Football player from
Arizona who joined the US Army and was killed in Afghanistan.
Work
on the bridge started in 2005 and should finish next year. An
estimated 17,000 cars and trucks will cross it every day.
The
dam was started in 1931 and used enough concrete to build a road from
New York to San Francisco.
The stretch of water it created, Lake Mead, is 110 miles long
and took
six years to fill. The original road was opened at the same
time as
the famous dam in 1936. More photos below .
An
extra note: The top of the white band of rock in Lake Mead is
the old
waterline prior to the drought and development in the Las Vegas area.
It is over 100 feet above the current water level.
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