DYWIDAG Threadbars secure terrific view over the Grand Canyon
Grand Canyon Skywalk, Grand Canyon West, AZ, USA
The Grand Canyon Skywalk is the newest tourist attraction in Grand Canyon West, about 200 km east of Las Vegas. This attraction was made possible by entrepreneur David Jin from Las Vegas in cooperation with the Hualapai tribe who owns the land there. The joined forces of the consultants, engineers and contractors involved cooperated to insure the trouble free execution of this spectacular project.
The new Skywalk, a glass-bottom horseshoe-shaped bridge, cantilevers over the edge of the Grand Canyon, 1,200 m above the Colorado River, and protrudes 20 m from the rim at its extremity.
The horseshoe-shaped glass-steel construction is designed for a maximum load of 35,000 t. It withstands wind forces of up to 160 km/h and earthquakes of magnitude 8 within a distance of 75 km.
A special proposal by the D.J.Scheffler construction company resulted in the use of micropiles to anchor the foundations instead of simply drilled foundation piers. The engineers involved welcomed this suggestion since the use of micropiles was also the most economical solution. The high-strength cement grout required for the installation of the micropiles could be directly mixed on site and subjected to local quality control. If concrete piles had been used, significantly larger quantities of ready-mixed concrete would have been necessary. In addition, due to the long transportation route, this concrete would have been about to set at the time of its arrival on the construction site.
Since the bridge was founded in massive original sandstone, micropiles utilizing high strength 65 mm diameter threaded steel bars could be used. For this purpose, DSI supplied 1,370 m grade 150 DYWIDAG Threadbars with an ultimate capacity of 3,470 kN that were pre-assembled to a total of 108 micropiles on site and installed. The giant steel girder for the Skywalk skeleton was welded together on the rim of the canyon and subsequently anchored freely floating above the Grand Canyon in a jack-and-roll action. The steel girder was lifted by means of the DYWIDAG Lifting System with a capa - city of 500 t.
The excellent cooperation of all parties involved in this technically very challenging project now allows all visitors who dare to walk onto the glass platform unforgettable views into the Grand Canyon.