The 800,000 square foot condo development is built on a standard flat slab. The square column concrete-framed building has two large cores, which are uniquely shaped and have floor-to-ceiling heights that vary throughout.
To meet the demands of this particular building design, it is necessary to cycle the vertical formwork at the same speed as the horizontal formwork. Walsh Construction Company wanted to pour the slab and floors monolithically and needed a forming system that could easily meet those challenges. Additionally the formwork system had to be capable of carrying a concrete placing boom, provide support for heavy loads (rebar) and be an easy-to-handle system that could keep them on a one-day cycle. For these reasons Walsh chose Doka’s Super Climber self climbing form system with working platform for high-rise cores. The Super Climber system, Doka’s newest member of their multiple climbing formwork systems, meets the tough requirements of extreme dynamic loadability with swift, smooth climbing. Also, Doka’s X-climb automatic climbing formwork is being used on the north core.
“The Super Climber was chosen because of its simple anchoring application and the ease of a component bracket base setup. The high load-bearing rigid super structure is engineered for a mounted concrete placing boom, and the impressive hydraulic climbing cylinders and pump provide us with a safe, fast and efficient lift from floor to floor,” said Steve Likens, Superintendent, Walsh Construction Company.
Using two self climbing core systems would allow Walsh to cycle the cores as fast as the slabs. Doka’s systems allowed for prefabrication of panels and platforms which help limit the amount of onsite work. By using Doka’s formwork Walsh could meet their schedule and minimize the amount of man-hours on the project.
The 39-story structure needs approximately 2,300 square feet of formwork. There are varying floor-to-floor heights with two double jumps. A total of five Super Climber hydraulic cylinders are used to climb a fully decked Level +1 and Level 0. Custom beams support a concrete placing boom and Framax stripping corners are incorporated into the Top 50 wall formwork for easy stripping relief. Formwork used included: one Super Climber system with Top50, one X-Climb with Top 50, Frami lightweight formwork for columns, eight MF240 platforms, 54,000 square feet of Dokaflex hand-set system and 72,000 square feet of reshoring materials.
The Super Climber self climbing core system also offers faster cycle times. The system allows inside and outside forms to be hung from the gantry, which allows the contractor to roll forms, while erecting and stripping. All of the formwork for an entire story is raised independently of the crane. Minimum clearance is required for installation and minimum stripping required for climbing. A placing boom with a working platform can be attached to the gantry to provide access. Forms, platforms, and the placing boom are all cycled at the same time with minimal climbing time. Climbing can be completed in one singular smooth movement. Service loads can stay on the platforms while they are being raised.
“The system is great to work with and climbs in less than 20 minutes, meeting our demands,” said Matt Code, Carpenter Foreman, Walsh Construction Company.
“The Super Climber system was used to climb the mounted placing boom. The rigidity of the superstructure in cooperation with the Super Climber hydraulic cylinders provides the contractor with an elite formwork system capable of carrying high loads and providing safety,” said Nicholas Zaraza, Project Leader/Engineer, Doka USA, Ltd.
All operations can be carried out safely and quickly on the formwork’s large, fully enclosed workspace, because the climbing formwork system is anchored to the concrete at all times. The whole “site” is repositioned hydraulically with just one lift. This self climbing core system is a safe and efficient way to construct high-rise cores. It has room for all of the site equipment needed and is enclosed on all sides for a safe, weather-shielded working at any height. The live loads on the platform mean that less storage space is needed on the ground. After pouring, the formwork for an entire next story is raised by powerful hydraulic cylinders from one casting section to the next.
Walsh has been extremely pleased with the Super Climber system and has already committed to use this effective solution on their next concrete core project.
The project was delivered at a competitive price because the formwork lowered the man-hour cost. Also, the project will be completed on schedule due to the ability to cycle the formwork floor to floor. Work on 2520 North Lakeview began in August 2010 and is scheduled for completion in July 2011.