When an eagle flies, it gathers power, takes off and then glides far above the ground. That’s how Las Vegas Developer David Jin wanted people to feel when standing at the front of the u-shaped Grand Canyon Skywalk on a glass floor, cantilevered 70 feet from the canyon’s west rim and suspended 4,000 feet over the canyon’s base.
Lochsa Engineering and MRJ Associates in Las Vegas partnered with two Las Vegas contractors, APCO Construction and Executive Construction Management, to make this happen safely, securely and without disrupting the canyon’s breathtaking beauty.First of its kind
The team first tackled remote, rough terrain that lacked the usual utilities found at a construction site and an unpaved, bumpy road to transport supplies.
“There was no power, no water, nothing,” says Contractor Manuel Mojica of Executive Construction Management. “There were just snakes, rocks, dirt and wind. And, you’re several hours from the closest town. You had to bring everything in with you.”
Once on site, the team faced the hurdle of creating and installing a sturdy, safe enclosed walkway – one that would weigh more than 1 million pounds when complete – in a way that didn’t affect the canyon’s integrity, as requested by landowners, the Hualapai Tribe.
“There were many logistics to consider,” recalls engineer Bill Karren of Lochsa Engineering. “It took a lot of thinking to determine where to put the supportive box beams, what shape the beams should be and how to get those beams into place. Then, you had to ask yourself, how do you build it? Do you build it in place, or do you build it on the ground and move it into place? And, you had to do it all without impacting the canyon itself. The tribe didn’t want its rock disturbed more than necessary.”
Putting it together
The team opted to build first, and then move. It devised, with the help of geotechnical engineers, an anchoring system to fasten the walkway to the top of the cliff in a way that didn’t require excavation or cutting into the sides of the canyon.
Crews then welded the many 40-foot steel beams comprising the skywalk’s frame, fabricated in Salt Lake City by Mark Steel, using welders from Lincoln Electric, to support beams on the ground near the site where the skywalk would cantilever over the canyon. Welding took four months to complete and encompassed what Karren calls, “thousands and thousands of feet of field welding,” with robust, full-penetration welds.
Although welds appear to just be molten metal that hardens to bond with other metal, they played a crucial role in the construction process and the walkway’s structural integrity. To create the strongest, safest bridge possible, each individual weld underwent stringent testing, including X-ray examinations, before the skywalk was moved into place. The skywalk is strong enough to support about 71 million pounds, or about 71 fully-loaded 747 jets.
“Welding was everything on this,” notes Contractor Cliff Rogers of APCO Construction. “Everything needed to be done properly. The welds are what hold it all together.”
The team took its inspiration from the Egyptians who built the pyramids, using the same rod-and-plate method as these ancient contractors did. The process took two days and a lot of brainstorming to complete.
“We rolled the structure on padded, steel bars and hooked up to two trucks that would pull away from the cliff. This movement would launch the cantilevered beams and glass deck out over the cliff,” Karren explains, adding that they also had two “stopper” trucks in place, “just in case.” And, they also placed heavy counterweights on the box beams so that when the structure moved into position it didn’t fall over the cliff.
“It took some pretty creative thinking from a number of companies to move that bridge out to position,” Karren says.The payoff
And even though they had spent years on this job, to say what they saw that first time out on the completed skywalk astounded them would be an understatement.
“It’s really hard to duplicate the Grand Canyon, “ says project architect Mark Johnson of MRJ Associates. “Working on this project was a once-in-a-lifetime experience. That didn’t hit us initially. We were there to solve the challenge. At the time, we didn’t realize how big it was and how much it really did change our lives. It really was something special to be part of. I would do it all over again without question.