The Colorado River Bridge, part of the Hoover Dam bypass project, now diverts the majority of traffic off the dam.

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This engineering project, required the creation of a 1060-ft twin rib tubular concrete arch springing simultaneously from the Arizona and Nevada sides of the Black Canyon towards their eventual rendezvous approximately 850 feet over the Colorado River. The 1900 ft bridge is the longest concrete arch span in the US and the fifth longest in the world.

Construction

Work began in 2003 on the approaches in both states and the construction contract for the arch bridge was awarded in October 2004.

The bridge and the bypass were constructed by a consortium of different government agencies and contractors, among them the Federal Highway Administration,  Arizona Department of Transportation, Nevada Department of Transportation, RE Monks Construction and Vastco, Inc, constructing the Arizona Approach, Edward Kraemer & Sons, Inc, the Nevada Approach and Las Vegas Paving Corporation undertaking the roadway surfacing on both approaches.

Construction required hoisting workers and 50 tons of materials 890 feet above the Colorado River using 2,300 ft long steel cables held aloft by a “high-line” crane system. High winds caused a cable way failure in September 2006, resulting in a further two-year delay. The approach spans, consisting of seven pairs of concrete columns—five on the Nevada side and two on the Arizona side—were completed in March 2008. 

14lives_slide6The arches are made of 106 pieces (53 per arch) 24 ft cast in place sections. The arch was constructed from both sides of the bridge concurrently, supported by diagonal cable stays strung from temporary towers. The twin arch spans were completed with the casting of the centre segments in August 2009. That same month, the two halves of the arch were completed. The temporary cable stays were removed, leaving the arch self-supporting. By December, all eight of the vertical piers on the arch had been set and capped, and at the end of the month the first two of thirty-six 50-short-ton (45 t) steel girders had been set into place.

By mid-April 2010, all of the girders were set in place, and for the first time construction crews could walk across the structure from Arizona to Nevada. Shortly thereafter, the pouring of the bridge deck began. The bridge deck was fully paved in July, and the high-line cranes were removed from the site as the overall project neared completion. The bridge was completed with a dedication ceremony on October 14, 2010 and a grand opening party on October 16.

It was opened to bicycle and pedestrian traffic on October 18 and to vehicular traffic on October 19. A few weeks earlier than estimated.

Check out some of the breath taking photos during the construction of the bridge.

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Article source: Mike O’Callaghan–Pat Tillman Memorial Bridge

Pictures: Jamey Stillings