This year, the U.S. Department of Energy presents its fifth Solar Decathlon, a biennial competition that calls for green innovations in the construction of the future. For the first time in its history, they will be judging a home constructed of precast concrete.
One of the 20 teams participating in the competition is Team New Jersey, which includes students and faculty from The State University of New Jersey (Rutgers) and New Jersey Institute of Technology (NJIT). The team designed the concrete panels to employ a wide variety of special conditions. Based on a beach house design, “eNJoy: A Generation House” incorporates architecture with solar panels and other integrated systems to function as a completely self-sustaining home.
Northeast Precast LLC of Millville, N.J., stepped up to manufacture the precast components for the project. “We do precast homes and commercial buildings every day,” says John Ruga, president of Northeast Precast, “but this was a unique opportunity to push the envelope and see what could be done with precast.”
To address some of the new technological challenges of the design, Ruga enlisted the help of supplier A.L. Patterson Inc. and Patterson’s affiliate Nycon Corp. With the experience and knowledge of Barry Fleck and Skip Francies of Patterson and Paul Bracegirdle of Nycon, Ruga put together the team that would attain project goals.
Northeast Precast produced more than 30 pieces of THiN-Wall insulated precast panels, none of which were identical in shape, size or weight. The house was first erected in late July on the NJIT campus in Newark for student and faculty evaluations. It is to be disassembled and transported to the National Mall in Washington, D.C., for the 2011 Solar Decathlon and then disassembled and transported again back to New Jersey. The ability to sustain structural integrity and appearance of the concrete panels added to the challenge, which required unique ways to reinforce, lift and handle these pieces safely.
One of the problems they faced was determining how to lift the panels without affecting the thermal performance of the system. This has always been the case with insulated precast wall panels, and none of the existing lifting and handling systems could eliminate the thermal bridging, so they created an entirely new lifting system. The result was a new patent-pending, three-part system named the Quik-Lift Zero Series made up of a reusable center lifting plate and two “wings.” The wings are cast into the exterior and interior wythes using tension reinforcing to lift and support each wythe separately. The lifting plate is bolted to the wings and then the lifting clutch lifts and moves the panel into place. Once the panel is secured, the plate is removed, totally eliminating the thermal bridge.
Since the panels were constructed of 3 to 4 inches of poured concrete sandwiching a foam-insulated core, there were few options for strengthening the concrete. This was necessary to prevent cracking during manufacture and particularly during lifting and handling. The solution was to add a blend of two types of Nycon-PVA fibers to the concrete mix: a micro-fiber for crack resistance during production and curing and for overall toughness, and a macro-fiber for providing increased modulus of rupture and post-crack strength to the panels.
The project shows that a bond between a producer and supplier is integral to creating durable, attractive concrete products. So whether the eNJoy house wins the 2011 Decathlon competition, it will forever stand as a monument of great accomplishment and teamwork.
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