World’s Largest Preassembled Metal Domes Raised in Annapolis
September 2008The world’s largest ground-assembled metal domes were lifted into position atop the 16-story condominium named Grandview at Annapolis Town Centre at Parole on July 19, 2009, in Annapolis, Md.
The three 38-foot diameter metal domes were assembled and installed by CitiRoof Corporation, Columbia, Md., and were manufactured by Lancaster Domes, Mount Joy, Pa. The domes are made of roofing metal coated with Kynar® polyvinylidene flouride in a copper patina-look green. They were assembled on the ground over the course of five days, and lifted by crane into position 150 feet above ground and firmly secured in just over eight hours.
The architectural metal domes, a visible landmark in this historic city, are believed to be the largest ever preassembled on the ground then lifted into place.
"It was a learning experience for everyone on our team,” said Lee Goldhammer, president of CitiRoof, the project’s roofing contractor. "We worked closely with Lancaster Domes to coordinate the procedure, adding the structural reinforcement required by our engineer, and of course the assembly and lift approach. We really appreciate that most of the work was done on the ground, which greatly increased the safety factor for our crew.”
Ken Musser, president of the company making Lancaster Domes, knew that the company’s dome roof technology, where thin, triangular, curved metal panels link to form the dome, was being stretched to the limit.
"We had never built a dome roof this large, let alone three of them,” Musser said. "Our largest standard size is 34 feet in diameter, but at this size an extra measure of precision becomes critical if the entire dome is to be assembled smoothly. Our manufacturing team rose to the challenge and did an excellent job.”
Each dome features a steel angle-iron base ring, forming the diameter at the bottom, and a top ring, where a 4 foot opening is covered by matching material. There are 66 fabricated panels, each like a very thin curved pizza slice, that join together, held by special metal clips.
The domes are designed for ground assembly, which helps keep installation teams safer than when working at potentially dangerous heights.