River Remedy
Work Continues on Hoover Dam Bypass
By Tony Illia

Significant drilling, blasting and embankment work are under way on the Nevada side of the $235 million Hoover Dam Bypass Bridge.

The progress comes none too soon.

A need for another route over the Colorado River dates back to the 1960s. As it stands, the two-lane U.S. Highway 93 over the dam is a major commercial corridor identified in the North America Free Trade Agreement between the United States, Mexico and Canada. But since Sept. 11, truck traffic over the dam has been rerouted 23 mi. away, costing the industry an estimated $30 million annually.

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The Federal Highway Administration is fast-tracking construction by awarding two of the four contracts needed to complete the 1,900-ft.-long, four-lane bypass bridge, which also includes 4.3 mi. of accompanying roadway.

Edward Kraemer & Sons Inc., of Plain, Wis. is performing the $30.1 million Nevada approach, while R.E. Monks Construction Inc., of Fountain Hills, Ariz., and Chino Valley, Ariz.-based Vastco Inc., are building the $21.4 million Arizona approach.

A consortium led by HDR Inc., of Omaha, Neb., Jacobs Inc., of Pasadena, Calif., and San Francisco-based T.Y. Lin International is serving as the project's architect/engineer.

"There are significantly more constraints and logistical challenges to the Nevada approach," said Dave Zanetell, the Highway Administration's project manager. "There is more volume in terms of material and structures."

The 2.2-mi.-long Nevada approach stretches from U.S. 93 to the new Colorado River Bridge crossing, approximately 1,500 ft. downstream of the Hoover Dam. It includes a new asphalt roadway with two lanes in each direction divided by a concrete median.

There are also five new bridges, including a 465-ft.-long, cast-in-place box girder structure with a 12-ft.-tall, 24-ft.-wide wildlife crossing underneath.

The project requires a total of 1,500 tons of reinforcing steel to complete.

Kraemer is additionally building a diamond interchange just east of the Hacienda Hotel Casino to provide access to the existing U.S. 93, which will become the Hoover Dam access road.

The most impressive bridge is a 463-ft.-long, three-span, steel-girder structure that crosses over a 160-ft.-deep ravine.

Mike Motil, Kraemer's senior project manager, said a 300-ton crawler crane with 200 ft. of lattice boom must be moved to the bottom of the ravine. It will be used to help place the supporting piers, abutment caps and structural steel.

Meanwhile, two hydraulic truck cranes will be used at either end of the span to help position the steel and bridge decking into place. To achieve the right angle for construction, Kraemer shaved 150 ft. from one of the canyon walls.

The rugged topography of tuff and basalt rock has resulted in some difficult excavation. KLB Construction Inc., of Lynnwood, Wash., is performing $12 million worth of excavation, drilling and blasting. The work must occur in a piecemeal fashion, carefully carving out the mountainside to correct the depth and pitch.

The material is being screened and used for 50,000 sq. ft. of mechanically stabilized earth retaining walls, averaging 20 feet. high, along the highway.

"There are approximately 1.6 million cu. yds. of excavation, said David Lingle, KLB's project manager. "There are six drills on the job, plus five 60-ton rock trucks, two articulated rock trucks and four excavators."

Other contract work calls for a small extension to the National Park Service's river mountain loop trail, plus various storm drainage structures. About 4.5 mi. of 7-ft.-tall game fencing will be installed to protect natural wildlife such as the big horn sheep and desert tortoises in the area.

"Kraemer & Sons have played an important part in getting the overall bypass started," Zanetell said. "The Nevada side is a real challenging job in terms of phasing and scheduling, but [Kraemer] has been real strong in paying attention to those details."

Kraemer expects its workforce to peak at 60 people, finishing the project well in advance of its October 2005 deadline. Funding delays from the reauthorization of Transportation Equity Act for the 21st Century, the federal road and highways bill that expired last year, has pushed back the bridge's final completion date to 2008.

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