An excavator works Thursday at the base of a man-made cliff above the Colorado River where one of the support footings will be placed on the Arizona side of the Hoover Dam bypass bridge. The pattern of dots on the cliff face is a series of devices drilled into the wall to serve as reinforcement. Photos by Clint Karlsen.
High-line towers on the Nevada side of the Hoover Dam bypass bridge project will support a cable-way crane that will be able to move out over Black Canyon as the bridge is built.
After nearly three years of work on solid ground in Nevada and Arizona, the Hoover Dam bypass bridge project is about to move into the empty space of Black Canyon, 900 feet above the Colorado River.
By Feb. 1, contractors expect to complete the installation of a massive crane that will be able to move across the canyon on overhead cables.
Advertisement
From the crane, workers next year will pour the bridge's twin concrete arches in midair, one 25-foot section at a time. The process is expected to take 16 months, said Michael Motil, project manager for bypass general contractor Obayashi/PSM.
"What people are going to see (in 2006) is us inching our way out (into the canyon). They're going to see us moving very slowly," Motil said.
Federal highway officials hosted a public meeting in Boulder City on Thursday night to update residents on the bridge project. About 15 people attended the meeting, which was the first of several project officials plan to have as the bridge marches toward its scheduled completion in the second half of 2008.
The 1,905-foot bridge will carry traffic on U.S. Highway 93 across Black Canyon just downstream from the dam.
"The job is going extremely well. We're pleased that we continue to be on track," said Dave Zanetell, who manages the bridge project for the Federal Highway Administration.
"In terms of the Hoover bypass in 2006, we will see the beginning and significant progress on the actual arch span across the Colorado River," Zanetell said. "We'll see construction of the columns on the approach-span portions of the bridge. We'll also see the completion of the high-line towers and cable-way crane."
Motil said the towers will be finished and the cable strung across the canyon in January.
The crane should be operational by March 1, and the first section of bridge arch should be in place in the spring, Zanetell said.
Using floating forms positioned by the crane, the arches will be poured in 104 separate sections starting at either edge of the canyon and moving out toward the middle of the expanse.
"It's more cost-effective to cast (the arches) in place," Zanetell said.
As the work moves out into the canyon, the project is expected to reach its peak workforce of about 350 laborers.
Excavation of the canyon walls to support bridge footings has been finished on the Nevada side and is about a month away from being done on the Arizona side, Motil said. That will essentially mark the end of blasting activity at the site.
Zanetell said the $234 million bridge project is on budget, and he expects it to stay that way now that the highway approaches in Nevada and Arizona are finished and the excavation is nearly done. "We have very few variables left," he said.
A mix of funds from Nevada, Arizona and the federal government will pay for the project. It officially got under way in January 2003, when construction began on the Arizona approach to the bridge. Construction of the bridge itself began on Jan. 31 of this year.
Asked whether the upcoming activity is more dangerous or delicate than what came before, Zanetell said there is nothing easy about any of the work.
"We're building one of the biggest concrete arch bridges in the world," he said. "That in its own right is a significant technical and engineering challenge."
