Apex Structural Design Creates Spectacular Suspension Bridge with Tekla Structures Software26 Sep, 2019 By: Cadalyst Staff
Winner of the 2019 Tekla BIM Award for Small Projects, the Whistler Skybridge is a vertigo-inducing pedestrian path made possible by accurate design — and a helicopter.
At the summit of Whistler Mountain in British Columbia, Canada, the Cloudraker Skybridge is a new 130-meter-long steel suspension bridge leading to Raven’s Eye Cliffwalk, a cantilevered viewing platform anchored into rock and projecting 12.5 meters out from the mountain’s edge. At more than 2,100 meters above sea level, it is thought to be the highest pedestrian bridge in North America, giving visitors the chance to literally walk in the clouds and take in spectacular 360-degree views of the Whistler Valley and surrounding mountains.
This design–build project was an impressive feat of engineering and construction, and designed for year-round operation for pedestrians, snow, ice, wind and seismic loading. The Skybridge is supported and stabilized by four steel cables, each with an ultimate capacity of more than 2,250 kN (500,000 lbs) and fixed to the mountain at each end by 14 steel grouted bedrock anchors. Both structures have open-grate steel decking and the main bridge has 101 removable deck modules that allow for decommissioning and maintenance during the off-season. The Cliffwalk is supported on four main steel beams that are held in place with six vertical rock anchors. The beams, which weigh over 5,000 pounds each, were flown into place with a Kaman K-Max dual-rotor helicopter until the anchor nuts were installed.
This project presented numerous logistical and technical challenges, including unpredictable weather at almost 7,000 feet above sea level, and a short construction timeline that would ensure opening in the summer of 2018. With the potential for heavy snow and ice in the winter months, the Skybridge and Cliffwalk viewing platform had to be erected quickly and efficiently, leaving no room for time-consuming errors or rework.
Alberta-based Apex Structural Design Ltd., which provides steel detailing, design, and building information modeling (BIM) services, relied on Trimble’s Tekla Structures — a structural software application for BIM — to model the project’s complex geometry. With Tekla Structures, Apex Structural was able to easily model the complex sloping geometry required by A-frames on each end of the Skybridge, as well as the curved beam and camber requirements of the Cliffwalk viewing platform. In addition, the drawings were automatically generated from the Tekla Structures constructible model, which helped Apex avoid errors and stay on track.
Tekla Structures helped ensure the project was completed on time and without issues. Apex Structural was able to model the project in Tekla Structures with full detail and automatic clash checking so that any conflicts were exposed in the model, not on the shop floor or onsite. The constructible model contained everything needed for fabrication and construction, down to the connections, bolts, and welds. It also ensured everything would line up properly, and that anchors were correct, which was especially critical for the cantilevered deck platform, since it had to be installed via helicopter.
Apex Structural Design won the 2019 Tekla BIM Award for Small Projects for the Whistler Skybridge.