Span for Hoover Dam bypass nearly done

For decades, tourists have paraded across Hoover Dam to admire the engineering marvel that once was the world's largest electric-power generating station. These days, the dam is serving more as a viewpoint for a new generation of spectacular: the Hoover Dam bypass.

Visitors continue to snap pictures from the dam deck, but few are pointed north toward the draining lake.

Many are trained on the developing arch, where crews work nearly 1,000 feet above the Colorado River and 250 feet above the tourists.

The bypass will soon be more than a tourist attraction.

The span, which will be the longest concrete arch bridge in the Western Hemisphere when it is completed in 2010, will provide a speedier, more convenient and safer way to traverse the Black Canyon and travel between Arizona and Nevada.

"This is the biggest of its kind and the first of its kind," project manager Dave Zanetell said Friday as he escorted members of the media onto the approach to the bridge. "The quality of work out there is second to none."

Six feet separate the Arizona and Nevada sides of twin massive concrete arches that will support the Hoover Dam bypass.

While six feet out of 1,060 feet -- the length of the arch span -- doesn't sound like much, it is still expected to take two months for the arches to be connected and completed.

The gap is scheduled to be filled by the second week of August, then crews will remove supporting cables and finish forming and stabilizing opposing legs of each side of the arches.

Completion of the arches is a significant milestone for the bypass, which is expected to be open to traffic in late 2010. Zanetell said it will take another 11 months to erect concrete columns, complete steel work and install the deck.

Paving the entire new segment not only includes the 1,900-foot span but also miles of roadway and seven bridges leading up to the canyon.

Some 1,200 construction workers and 300 engineers have battled Southern Nevada's weather, including extreme heat and high winds, but Zanetell said the project remains within its $240 million budget. He said it is also considered to be on time since the new opening date was set about three years ago.

"This is not an easy job to do anywhere in the world, but this is one of the extreme harsh places," Zanetell said.

The project was delayed in 2006 after two 280-foot-tall steel cranes collapsed. The bridge was originally scheduled to open at the end of this year.

"We haven't had any slippages in the last few years," Zanetell said.

Although the Hoover Dam provides the best vantage point for tourists interested in the bypass project, the new span will return the favor when it is completed.

Visitors will be able to park their cars near the bypass bridge and follow a trail to a deck where they will be treated to a new, unobstructed view of Hoover Dam.

Contact reporter Adrienne Packer at apacker@reviewjournal.com or 702-384-8710.