Las Vegas Observation Wheel Reaches Record Heights
The world's largest observation wheel is racing toward completion on the Las Vegas Strip. The 550-ft-tall High Roller is the centerpiece of gaming giant Caesars Entertainment's $550-million Linq development. True to its name, the project links together three resorts with 200,000 sq ft of shops, restaurants, bars and entertainment.
Scheduled to finish later this year, the quarter-mile-long development will improve visitor amenities between three hotel casinos: The Quad, Harrah's and the Flamingo. The trio of contiguous Caesars-owned properties are spread over 350 acres bound by South Las Vegas Boulevard, East Flamingo Road and Audrie Street.
However, Linq's unmistakable star attraction is the 28-cabin, 1,120-passenger High Roller, which will be 107 ft taller than the London Eye and larger than the current record holder, the Singapore Flyer. It will face north and south, parallel to Las Vegas Boulevard. American Bridge Co., Coraopolis, Pa., is the general contractor, with the San Francisco office of Arup as engineer-of-record.
"Like a bicycle wheel, the High Roller will be constructed with tensioned spokes and a rim that is kept in compression," says Jason Krolicki, Arup associate principal. "The design is not only structurally efficient but also yields superior fatigue performance to fairground-style Ferris wheels."
Big Wheel, Big Specs
The 520-ft-dia wheel remains in compression through each revolution, thereby preserving welded joints and limiting fatigue cracks due to fewer connections than a traditional rigid steel strut configuration. The 5,000-ton wheel will move at a rate of 1 ft per second, powered by eight hydraulic drive motors from Enerpac, Netherlands; it's designed to operate 18 hours a day for 50 years, or roughly 657,450 full rotations.
"From the start, the objective was to build the tallest wheel in the world," says Linq executive project director David Codiga. "It will be a spectacular landmark built upon the experience of more than a century of Ferris wheel design."
The Vegas wheel is supported by two pairs of 285-ft-long, 9-ft-dia canted legs and a 330-ft-long, 52˚ transverse brace leg. The legs are anchored by three concrete plinths set atop pile caps and tied together by grade beams over 32 drilled shafts. The 2.5-in.-thick plate-rolled support legs contain 13 tuned mass dampers that counteract structural vibration. The wheel is designed to withstand a seismic event.
Together, the legs support a 546-ton hub assembly that rotates using two custom-designed 7.55-ft-dia spherical roller bearings on either end of an internal spindle. The 2-ft-thick, 19,400-lb bearings are among the largest ever manufactured by SKF of Gothenburg, Sweden. The bearings were installed on the spindle ends on the ground, then inserted into the hub ends. The spindle transfers the wheel weight through the legs, while the hub connects to a single element rim using 25,256 ft of tensioned cable.
The 100-ft hub is four times longer than the London Eye, resulting in a more inclined and effective cable angle for resisting out-of-plane loads. The High Roller can withstand 90-mph winds. A longer hub also lowers cable pre-stresses, thereby reducing the circumferential rim loads for a lighter wheel. The hub connects to a rim using 112 locked-coil cables tensioned at 250,000 lb. The 3-in.-dia, 225-ft-long cables each have a breaking force of 600 tons.
"To enhance the wheel's resiliency, the rim was designed to withstand the force of a dynamic cable break," Krolicki says. "In this case, the other cables are able to redistribute the load and still maintain structural stability."
The High Roller has a slim profile with a 6.6-ft-wide rim that maximizes passenger views while creating an eye-grabbing sleek aesthetic important on the Strip. The 44,000-lb cabins attach at three places to the rim using double-V frames. The 22-ft-dia cabins are encased with 300 ft of doubly curved 360˚ glass. Capsules stand 6.5 ft off the rim for greater unobstructed visibility. Grand Junction, Colo.-based Leitner-Poma of America Inc. is the design-build cabin contractor.