BOULDER CITY, Nev. (AP) _ The governors of Nevada and Arizona joined five federal lawmakers at Hoover Dam recently to announce the start of construction on a bridge bypass project that will ease congestion and safety concerns at the dam.
The $231-million project – not yet fully funded – would create a 2,000-ft. (609 m) bridge over the Colorado River just south of the dam. It is expected to end growing traffic delays along U.S. Highway 93, the winding two-lane road that links Las Vegas and Phoenix.
Central Federal Lands Highway Division (CFLHD) of the Federal Highway Administration is acting as manager of construction and design, with HDR Engineering Inc. providing design and construction support.
The steel and concrete arch will span the Colorado River about 1,500 ft. (457 m) downriver from Hoover Dam. About 2 mi. (3.2 km) of highway will be added on either side of the dam to reach the bridge. Construction of the Arizona highway approach is set to begin in January.
In response to public comment during the Environmental Impact Statement process, the design team was charged with devising practical ways to enhance the visitor experience and provide unique views of the dam. The final design will include a parking lot, a trail to the new bridge, a pedestrian plaza and a sidewalk on the bridge.
Described as a composite concrete deck arch bridge, the design would use concrete in compression for the arch and lighter steel for the upper structure.
According to project designers, concrete will be used where it is most economical, and will be placed using a form traveler system considered a proven technology for this type of work
The concrete composite may allow for an accelerated schedule, since the concrete arch can follow on an early foundation excavation contract without the wait for fabrication of arch steel.
A steel superstructure is intended to reduce the risk of construction delays, and could eliminate many quality control issues inherent with a cast-in-place concrete superstructure in the open environ surrounding the gorge.
The project also is designed to enhance security at the dam.
An estimated 13,000 cars and trucks cross Hoover Dam daily. Authorities tightened security around it immediately after the Sept. 11, 2001 terrorist attacks and vehicles are still stopped at checkpoints on either side of the dam.
Preparations for bypass construction began in mid-October. Crews could begin building the four-lane bridge as soon as 2003, but the project likely will not be completed until 2007.
“You can’t finish something until you start it,” Nevada Gov. Kenny Guinn said of the bypass, first discussed by federal officials two decades ago.
Guinn and Arizona Gov. Jane Dee Hull placed a foot-long bridge into a model of the dam area following a ceremony on the visitor center observation deck.
“Notice the Nevada side went in first,” Guinn joked.
Hull said the bridge, like the dam itself, would be “an engineering miracle.”
Sen. Jon Kyl, R-Ariz., hailed the bypass as a boost to commerce throughout the West and key to security at the dam, about 30 miles east of Las Vegas.
“This beautiful Hoover Dam here is a (terrorism) target because it stands for what America stands for,” he said.
Joining Kyl at the ceremony were Sen. Harry Reid, D-Nev., Nevada’s two Housemembers and U.S. Rep. Don Young, R-Alaska, chairman of the House Transportation and Infrastructure Committee.
Project leaders urged the lawmakers to include the bypass in federal transportation funding. Nevada and Arizona have each contributed $20 million, and $86 million in federal money has been allocated. Another $105 million is still needed to complete the project.
Since Sept. 11, 2001, tractor-trailers, full-sized buses and large campers traveling the main route between Las Vegas and Phoenix have been banned from the dam and must take a longer route through Laughlin, NV, and Bullhead City, AZ.
Officials said about 2,000 vehicles per day have made the 80-mi. detour, costing the trucking industry about $30 million per year in fuel and other costs.
Guinn and Hull, both Republicans, said the bypass will increase “crossover tourism” between Nevada and Arizona.
Owned by the U.S. Bureau of Reclamation with the U.S. Department of the Interior, Hoover Dam forms Lake Mead, the nation’s largest man-made reservoir. It also supplies electricity to a wide area of the Southwest. Completed in 1935, the dam is one of southern Nevada’s most popular attractions.
The first construction stage was set to involve moving a set of 230,000-volt power lines and two electricity towers now leaning over the river where the bridge is to be built.