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May/June 2009
Speed and Safety
Innovative self-climbing formwork helps fast-track a casino project in the Colorado foothills
By Tom Nicholson
ubcontractors must focus on expediency in these days of integrated project delivery and fast-track schedules, and they often accomplish this goal by using improved construction methods and innovative tools.
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| Sing self-climbing formwork to construct Black Hawk Casino’s two elevator cores brought expediency to the fast-track Colorado-foothills project. (Photo courtesy of Terry Shapiro) |
Hensel Phelps Construction Co., Greeley, Colo., a member of multiple AGC chapters, successfully pared its schedule at the recently completed 36-story Black Hawk Resort and Casino in Black Hawk, Colo., located in the foothills west of Denver, by making speed an objective for its subcontractors. When the team searched for time-saving measures in the schedule, it zeroed in on the building’s two concrete elevator cores as prime targets. Using self-climbing formwork to erect the concrete cores, the team shortened that portion of the project by two-thirds.
The job went to Little Ferry, N.J.-based self-climbing formwork subcontractor Doka USA Ltd., a member of multiple AGC chapters. “Self-climbing formwork is fairly common,” says Dave McLaughlin, manager at Doka USA, a subsidiary of Amstetten, Austria-based Doka. “But safety is an issue with self-climbing formwork, and we believe that few are as safe as our system.”
The team employed 30 of Doka’s SKE 50 climbers, with a rollback feature for cleaning, and more than 8,000 sq ft of formwork. The climbing scaffolds operate by staying continually connected to the structure, with the ability to climb ahead of the poured decks.
Hydraulic lifts do the vertical raising, eliminating the costs and requirements of using a crane to place the formwork. The formwork can climb 10 ft vertically every 15 minutes, a 60% reduction in time over regular formwork.
The crew started the job in September 2007, and completed one core in 13 months and the second in 15 months, McLaughlin says. “Every three to four days we could raise the formwork up for the next floor,” he adds.
Safety was bolstered by wide working platforms hugging the formwork of the core, which enabled the team to work fast. “We were able to stay ahead of our four-day cycle,” says Kiki Alvarado, Hensel Phelps’ general foreman on the project. “Even when using the system at heights up to 380 ft and in strong winds, our crew always felt safe.” The winds in the Clear Creek Valley near Black Hawk can gust to more than 60 miles per hour.
The rollback function of the formwork allowed the contractor to roll formwork away from the face of the concrete and clean the formwork before moving it to the next floor of the building. That saved time by eliminating the traditional “tilt-back” method of formwork cleaning.
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| AGC member firm and subcontractor Doka’s formwork system put safety against the high winds of the foothills on equal footing with speed. (Photo courtesy of Terry Shapiro) |
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