Hoover Dam Bypass Bridge (2010) The Arizona and Nevada border, USA
The Hoover Dam Bypass Bridge (Mike O’Callaghan–Pat Tillman Memorial Bridge) spans the Colorado River and the American states of Arizona and Nevada. It is located southeast of Las Vegas in the Lake Mead National Recreation Area.
For many years US Route 93 across the Hoover Dam was considered inadequate and unsafe for the increasing volume of traffic and plans to bypass it culminated in the Hoover Dam Bypass Project, a 3.5 mile corridor from Clark County, Nevada, to Mohave County, Arizona. The central element of this project was a new bridge 460 m (1,500 ft) downstream and high above the dam.
The bridge is a concrete and steel composite, single span arch design, the first of its type in the United States. The arch and columns are constructed of concrete and the deck of steel in a design which was considered compatible with the dam below. 243 million tons of concrete and 8,000 tons of steel were used during construction. The overall length of the bridge is 580m (1,900 ft) with a span of 320m (1,060 ft). The deck rises 274m (900 ft) above the river.
The arch was constructed from both sides concurrently. When the two sides finally met at the centre the gap between them was less than a centimetre, a remarkable feat considering the difficulties presented by working 900 feet above the river.Construction began in 2005 and was completed five years later despite a delay of two years due to the collapse of the construction crane cable system in high winds during 2006. The build cost $114 million.
Pedestrian access to the bridge is possible to allow viewing of the dam and river below. When the bypass opened the road across the Hoover Dam was closed to through traffic but it may still be accessed by visitors.
The official name of the bridge commemorates a former Governor of Nevada, Mike O’Callaghan, and Pat Tillman, a professional football player with the Arizona Cardinals who was killed in 2004 while serving with the US Army in Afghanistan.
Links: Wikipedia | The Story Behind the O’Callaghan-Tillman Memorial Bridge