The UCHealth Longs Peak Hospital “flying roof” structure is quickly becoming a landmark in the Longmont area – it can been seen from several miles away. And getting it in place was no easy feat!
“The roof is really the architectural centerpiece of the building,” stated Haselden project manager CJ Harvey.” The project was designed by WHR Architects with structural engineering by Datum Engineers.
Just the Facts
The flying roof structure weighs in at 270,000 lbs; because of the weight of the roof, coupled with the cranes being used, it qualified as a critical lift under OSHA standards. In this case, the locally-based Loveland steel erector, LPR Construction, decided on a tandem lift. Simply defined, a tandem lift involves using more than one crane or hoist, or using a crane or hoist in conjunction with another piece of powered lifting equipment. This alone constitutes a critical lift, however each individual crane was also lifting in excess of 75% of its rated capacity: a Manitowoc 888 was used on the west side and lifted 110,000 lbs. (80% capacity), and a Manitowoc 4100 was used on the east side and lifted 160,000 lbs. (79% capacity). A critical lift necessitates extensive preplanning meetings, as well a permit verifying crane capacity and load.
The Day It All Came Together
The half-day event was set in motion about a month earlier when LPR began assembling the flying roof on the ground via “stick building.” This allowed for safer and more efficient construction of the structure. Once complete, it was ready to fly.
After being rigged to the cranes, the cranes simultaneously moved the roof piece approximately 50 feet from where they were assembled to their final position. Precisely choreographing this movement required the expertise of skilled personnel—certified riggers and experienced crane operators and flaggers—to monitor conditions such as load distribution, cable height, and boom distance. Three Haselden safety managers remained on site during the operation.
This complicated tandem lift went off without a hitch! Kudos to LPR Construction for a great job building the flying roof and developing and implementing the critical lift plan!
Also known as a tandem pick or multiple crane lift. Defined as using more than one crane or hoist, or using a crane or hoist with another piece of powered lifting equipment.