New BC Place Stadium Roof, Vancouver
Completed in the fall of 2011, the new BC Place roof is the largest cable-supported retractable roof in the world. The roof is supported by 36 masts, each fourteen stories high, and weighs 135 tons. Thirty-five kilometres of cables arranged as 18 suspension bridges form the main part of the roof, over which 76,000m2 of fabric is laid.
This survey project included
- construction-related surveys,
- three dimensional laser scanning, and
- engineering surveys.
Go to BC Place stadium
See 3D animation of BC Place roof construction
Underhill was contracted by Montacier International to provide land survey services for the erection of the new cable-stayed roof for BC Place stadium in Vancouver. As the project progressed, others requested survey services, including Freyssinet and Buckland & Taylor. The fast-paced environment required accurate and timely surveys. Keeping up with hundreds of iron workers, cabling experts and engineers required the on-site presence of one three-man crew for roughly one year.
Work on the new BC Place roof began with the establishment of precise control network. This was followed by layout and construction monitoring of the temporary centre tower. Layout and adjustment of mast baseplates were among the next steps.
Meanwhile, two mast rotator/assembler machines were tuned up on the field of play. The rotator machine supported three mast sections during their alignment and welding. While a mast was in the rotator machine, an as-built survey was performed to confirm its alignment. Once installation of the masts started, a crane, one of the world's largest, had to be positioned to lift the mast and compression beam section. During the erection of major structural elements, masts were monitored for lateral and longitudinal inclination. Once many of the structural pieces were erected, Underhill surveyors climbed and walked the high iron compression ring several times while taking measurements to establish the geometry of the erected pieces.
The success of the unusual and demanding project required innovation, dedication and communication. Unusual problems required innovative solutions. Challenges included taking measurements from a constantly moving surface and taking remote measurements using a three dimensional laser scanner. Communication with site engineers, supervisors, and foremen at various levels and from several companies ensured timely information and kept the job moving forward.
A final as-built survey, requiring three crews and three total stations, had to be completed in one evening shift. The work was performed in the evening owing to calmer conditions for observing. The results were provided the next day to Buckland & Taylor for loading into their structural model. The center node was within 2mm vertical and 12mm horizontal of its design location.