Hoover Dam Bypass Bridge Rises Under a Shadow

The Hoover Dam bypass bridge looks spectacular, stretching 1,900 feet across Black Canyon and 900 feet above the churning Colorado River. Tourists visiting the world-famous Hoover Dam can't help but swing around and snap photos of the new span high above.

Long before its completion, it was labeled a "civil engineering marvel."

Perhaps the toughest challenges associated with building the long-awaited bridge linking Arizona and Nevada had less to do with technology and the daunting dimensions and more to do with respecting the true engineering marvel 1,500 feet upstream. At least that is the opinion of one well-respected civil engineer.

"I think the challenge was to make it come up to the iconic standards of the Hoover Dam, building something in such close proximity to a world-class structure like that," said Henry Petroski, a civil engineering professor at Duke University. "The engineers involved were very conscious of this, that they were working with a site that had to be respected."