Quite
the engineering project.
THE
WIDER VIEW: Taking shape, the new bridge at the Hoover
Dam
Creeping
closer inch by inch.
900 ft.
above the mighty Colorado River
the two sides of
a $250 million bridge at the Hoover Dam in America 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 ft. long
which have been cast on-site and are being lifted into place using an
improvised high-wire crane strung between temporary steel
pylons.
Spectacular: The new Hoover Dam bypass
The arches
will eventually measure more than 1,000 ft. 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.
