The Colorado River Bridge is constructed of 1,060 foot twin-rib concrete arches . The Colorado River Bridge is the central portion of the Hoover
Dam Bypass Project. Construction on the nearly 2,000 foot long bridge began in late January 2005 and the completion of the entire Hoover Dam Bypass Project is expected
in Late 2010. When completed, this signature bridge will span the Black Canyon (about 1,600 feet south of the Hoover Dam), connecting the Arizona and Nevada Approach
highways nearly 900-feet above the Colorado River.
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Building The Arches
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Building The Arches
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United States Highway 93 (U.S. 93) has been designated a North American Free Trade Agreement (NAFTA) route. The increasing congestion caused by the switchbacks
leading to the Hoover Dam site and the restrictions at the dam crossing have led to the development of the Hoover Bypass Project. The Hoover Dam Bypass Project
is a 3.5-mile corridor beginning at approximately milepost 2.2 in Clark County, Nevada and crossing the Colorado River approximately 1,500 feet downstream of the
Hoover Dam, then terminating in Mohave County, Arizona near milepost 1.7 on U.S. 93.
The type of bridge being built is Composite Concrete Deck Arch Bridge.
The composite solution was developed to address the specific design issues inherent to the Hoover Dam site. It is recommended on the merits of cost, schedule, aesthetics and technical excellence. The specific advantages of the concrete composite alternative include the following:
The concrete composite alternative blends the best of both concrete and steel, using concrete in compression for the arch, and lighter steel for the upper structure. Concrete is used where it is most economical, and is efficiently placed using a form traveler system that is a proven construction technology for this type of work.
The concrete composite offers advantages for accelerated schedule, since the concrete arch can follow on an early foundation excavation contract without the wait for fabrication of arch steel.
The concrete composite alternative is the lowest projected cost for the favored solid rib alternatives, and the blend of concrete and steel design detail options allows the greatest flexibility to design for cost efficiency.
The composite distributes construction risks in terms of costs, quality control and schedule. Concrete casting is completed in a confined form, and runs in parallel with steel fabrication. The steel superstructure reduces the risk of delays and eliminates many quality control issues inherent with a cast-in-place concrete superstructure in the open environ over the gorge. The composite structure utilizes concrete where it is most efficient and steel where it is most efficient.
The composite structure allows progress to occur in parallel on site during arch erection and in the shop for superstructure steel fabrication, with relative independence between these operations
The bridge and the new sections of U.S. Highway 93 will be four lanes wide. Total length of the bridge is 1,900 feet (579 m) with a 1,080 ft (330 m) main span.
The roadway will be 840 ft (260 m) above the river. When completed, it will be the first so-called concrete-steel composite arch bridge built in the United States.
The composite design, using concrete for the arch and columns with steel construction for the roadway deck, was selected for schedule and cost control while still
being aesthetically compatible with Hoover Dam. Pedestrians will be able to park and walk across the bridge for views of the Hoover Dam,
but the dam will not be visible to most drivers on the bridge.
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Mid 2006:
The bridge's construction was in its beginning stages when a permit problem between Clark County and subcontractor Casino Ready Mix arose over the operation of a concrete batch plant for the project.
April 2007:
The bypass and the bridge were under construction and large cranes were visible near the river when looking from Hoover Dam.
March 2008:
The approach spans were completed, consisting of seven pairs of concrete columns -- five on the Nevada side and two on the Arizona side. The spans will act as the springboard for the remaining segments, with two more cable towers to be built on them to complete construction of the bridge.
May 2009:
The concrete arch 50% completed, and on track for closure in the third quarter of 2009. A most of the arch segments have been cast in place using a temporary form traveler system. Other completed work includes the precast segments for the bridge columns which will support the roadway on the arch.
August 2009:
The twin arch spans were closed with the casting of the center segments. With the removal of the temporary cable stays, the arch is self supporting.
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