Hamilton Form ‘voids’ productivity limits at Unistress

Computer chip manufacturer Global Foundries began building its Fab 8 project in Saratoga County, N.Y., in 2009—the $4 billion-plus project representing the largest private capital investment in the U.S. against the prior year’s financial markets distress.

Precast/prestressed producer Unistress Corp. in Pittsfield, Mass., has played a major role in the construction at the site, especially for the semiconductor fabrication facility. A first phase included 1,362 precast “waffle slabs” with a series of cylindrical voids that supply ventilation for the facility’s clean room. The next phase of expansion at the site has entailed another fabrication facility, dubbed Fab 8.2, and presented Unistress and lead contractor M+W Group an opportunity to improve the design by incorporating lessons learned from phase one.

In collaboration with the design team, Unistress was able to replace some of the waffle slabs with more standard precast products, the schedule encompassing 1,296 double tees, beams, columns, flat slab and insulated wall panels, plus “tubby tees” and ”waffle slabs.” The latter were modified from the first phase, their lengths increasing from 22 feet to 34 feet. New formwork was designed with hinged sideforms that pivot back for stripping and two-piece headers to accommodate both straight and diagonal protruding rebar loops. The forms are self-contained, which enabled Unistress crews to quickly commence production once the Fab 8.2 contract was secured.


The Fab 8.2 building slabs are 34 ft. long, weigh-in at 34 tons each and have a total of 48 voids. Unistress realized productivity gains and waste reduction in the Global Foundries phase two waffle slabs by lengthening the profile from 22 feet in the initial phase, and eliminating disposable form voids.

Just as phase two presented an opportunity to improve design for more efficiency, Unistress was able to rethink its shop plan. The 1,362 waffle slabs produced for the first fabrication building had 26 voids in each formed with paper and glue. Hamilton Form designed the phase one waffle slab forms with steel alignment plates to locate and hold the voids in place during the pour. After the product was stripped and moved to the storage yard, the voids were removed and discarded during a secondary operation.
For the second phase of the project, Unistress wanted to reduce time, labor and waste by eliminating the use of the disposable materials behind the 35,000-plus voids in the phase one slab casting. Hamilton Form worked with the producer to develop a collapsible steel void that could be reused, eliminating both the disposal problem and the need for the labor-intensive secondary operation after stripping.

“We have a very user friendly and efficient system,” says Unistress Plant Manager Ralph Schwarzer. “The steel voids are quicker to set-up and because they collapse, it’s easier to strip the product. The result saved us a considerable amount of labor and material cost.

“It’s unusual to get a project of this magnitude once, but having the opportunity to rethink and improve our production system is truly fortunate,” he adds. “We hope the momentum continues and a third production facility at Global Foundries follows.” — Hamilton Form, 817/590-2111; www.hamiltonform.com