Hoover Dam bypass "a civil engineering marvel"

The Hoover Dam bypass "a civil engineering marvel" :

The two massive concrete arches jut out from the rock faces on each side of the river and are being built from 53 individual 24 foot sections that are cast on-site in order to support the highway.

They are 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.

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