Reaching beyond the Grand Canyon

The Hualapai Tribe and Grand Canyon West partner to create a glass bridge to experience one of the most beautiful natural wonders in North America.

by Clair D. Urbain

For many construction workers, working at heights is no big deal. After all, a fall from 6' can be just as deadly as a fall from 100'. With planning and conscientious use of fall protection equipment, the dangers of working in high places can be avoided.

But what about building a U-shaped glass bridge that juts out about 4,000' above the floor of the Grand Canyon? At more than twice the height as the world’s tallest skyscrapers, it creates more logistics problems than just worrying about fall protection. The remote location and the innovative design present special challenges that only experience and teamwork can conquer, say sources close to the project.

Less than friendly worksite
“Logistically, this isn’t a very friendly neighborhood for construction projects,” says Don Highsmith, ECM superintendent on the West Grand Canyon Skywalk project that’s underway 120 miles from the Las Vegas Strip. The location is so remote that the last 14 miles of the trip is on an unimproved, unpaved road that meanders through the Joshua Tree National Forest and the Grand Washed Cliffs nature area.

The Skywalk is the brainchild of Las Vegas entrepreneur David Jin and the Hualapai Nation on its one million acre reservation along the western section of the Grand Canyon.

“Just as an eagle can fly into the Grand Canyon, my vision was to enable visitors to walk the path of the eagle and become surrounded by the Grand Canyon while standing at the edge of the glass bridge. The bridge gives us a chance to share the wonder of the canyon that the Hualapai Tribe has graciously offered. My dream was to find a balance between form, function and nature,” says Jin.

It’s an engineering feat that is creating a cantilevered U-shaped glass bridge that will allow visitors to walk out 70' over the edge of the canyon and get an even more dramatic view of the vistas. Bridge pedestrians will also be able to look through the glass floor and see the Colorado River and canyon floor that is about 4,000' straight down.

Below: The white sections of the Skywalk will extend out over the canyon and will be covered with a glass floor and wall for an eagle-like view of the Grand Canyon.

The Hualapai Nation contracts with several interests to bring services and expertise that are needed to attract tourists to its breathtaking views at its Grand Canyon West’s Eagle Point development.

Jin brought together MRJ Architects, Lochsa Engineering, LLC, wind experts from RWDI and a variety of other experts to design the project. Three years in the making, it’s turned into a labor of love, says Mark Johnson, principal architect at MRJ Architects.

Construction on the Skywalk began in March 2004 and it is scheduled to open before April 2007. In May 2005, testing on the structure showed the design passed engineering requirements by 400 percent, enabling it to withstand the equivalent weight of 71 fully loaded Boeing 747 jets, equal to more than 71 million lbs. It can also sustain winds greater than 100 mph from eight different directions as well as withstand an 8.0 magnitude earthquake within 50 miles of the structure.

The 65'-wide pedestrian structure will extend 65' from the canyon edge. Its 10.2' wide, 2.2"-thick glass deck is supported by outer and inner structures made of 2"-thick steel-plate welded-box beams that are 32" wide and 72" deep.

The beams are anchored to eight 32"-square steel columns tied to 94 pieces of 2.5"-diameter rebar embedded 46' deep into solid, 16,000 psi-rated limestone.

“The tempered, five-layer composite glass attaches to the beams with special hardware that enables it to flex without cracking during climate changes. A 5' tall, .82"-thick laminated glass wall railing will skirt the structure to give it a transparent appearance,” says Johnson.

To counteract any vibration or movement set up by winds or foot traffic on the bridge, the box beams are outfitted with three 4,000 lb. tuned vibration dampers that sit inside the box beams, says Johnson.

“The beams are tall enough to walk inside of them. They will be accessible once the bridge is in place and may be open for special tours,” he says.

Sections of the box beams were brought to the site individually. Construction crews, using two Lincoln generator-powered welders, have welded the 21 sections together and then raised them 7' into the air by American Heavy Haulers of southern California so all welds could be examined with X-rays to assure proper assembly.

Concrete pads will be placed below the bridge and the beams will be outfitted with snowmobile-style skis that will ride on a rolling platform.

Before being rolled out over the cliff, counterweights will be added to the rear section of the bridge and the glass will be installed. “It will take more the 550,000 lbs. of trench plates for this counterweight,” says Highsmith. “Weight will be placed at both ends of the bridge and will slowly be removed as the 180,000 lbs. of glass is installed. After more testing, it will be ready to roll out over the edge.” Once all glass is installed and testing is complete, American Heavy Haulers and Dielco Crane will assist ECM with the bridge rollout.

Once the bridge is rolled into place, it will be anchored to the caissons embedded into the canyon. After that, a three-story 25,000 sq. ft. visitor center will be built over it at the canyon’s edge, serving as a museum, movie theatre, VIP lounge, gift shop and several restaurants and bars. A high-end Skywalk Café will offer patio and rooftop seating on the edge of the canyon; the second story will offer visitor access to the Skywalk. The design will blend in unobtrusively with the canyon’s natural features.

“It’s not as bad as some of the projects I have worked on in Alaska, but it’s 100 miles from anything. It takes some planning. About 35 people work on the site on 7,000 sq. ft. of space. There are five trades here and we work seven days a week, 12 hours a day,” says Highsmith.

“Everything runs off of our Lincoln electric welders and a few light plants that have generators that we can use for power during the day. We have needed some heavy equipment out here and it has been difficult to get it on site. There are no telephones – only satellite phones. It’s pretty remote, but it’s an interesting project.”

Above: Work continues around the Skywalk; the naturally occurring phoenix image in the cliff in the background is considered sacred by the Hualapai Nation.

Project of honor
Johnson concurs. “It’s an honor to be a part of this project, and how it came together has been very rewarding. Lochsa did a great job and this has been a great team. We were able to work with the engineers on the front end of this project. It is so much easier to figure out what’s needed on the front end. We brainstormed ideas and by having the architect, engineer, designers, the experts of the various studies and the owner together, it was so much easier to design. Early on, there were design changes, and we always had to be aware we were limited to what was available on site. There is no power or services one would normally find on a construction site.

“The road to the site is very bumpy. Each bridge section weighs up to 60,000 lbs., and we needed a crane that could unload and move these pieces on the site. To get the crane on site, the operators sometimes had to take it off of the flatbed and literally drive it through some areas of the canyon. The terrain was tough duty for the crane’s transmission and the operators had to stop at times to allow the transmission to cool before continuing,” says Johnson.

“As the site gets developed, we are looking at alternative systems to support visitors. There is no power out there to speak of and water must be brought in daily. We are looking at solar power, co-generation systems, satellite phones and Internet access. This all needs to be done,” says Johnson.

Below: The Hualapai Tribe educate visitors about their heritage at Grand Canyon West. Young dancers perform in the foreground while work continues on the Skywalk in the background.

Published in the March/April 2007 issue of Contractor Tools and Supplies magazine.

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