On March 2, the U.S. Patent Office granted patent 6,699,575 to Habib Dagher and William Davids, AEWC director and assistant professor of civil and environmental engineering respectively. The patent is assigned to the University of Maine System, meaning that UMaine has the right to license the technology for commercial development.
The panel increases the sheer strength and ductility of wall, roof and floor systems, says Dagher.
"The panel itself is expected to be useful in southeastern and western regions of the country at risk for high wind and seismic events, where more stringent construction measures apply," adds Davids. "Other potential uses that could impact the construction industry are currently being investigated at the AEWC Center, including applications in modular panelized construction and specially engineered narrow walls."
Research by AEWC graduate students Aaron Bremer and Eric Cassidy evaluated potential applications and optimum design of the patented technology. Keith Martin, a master's degree student at AEWC, is continuing to explore new potential uses.
At the heart of the technology is the addition of tough fiber reinforced polymer material to the perimeter and other nailing surfaces of building panels including oriented strand board and plywood. When storms and earthquakes cause homes and other structures to collapse, structural failure can often be traced to weaknesses where panels are nailed to framing members such as wall studs or roof rafters. Reinforcing those areas will reduce the likelihood that panel edges can be splintered or pulled away from the framing.
In typical house construction with nails and 2x4 framing, the reinforced panel improves wall strength up to 20 percent, says Davids. "In an engineered wall we can achieve 100% or better," he adds.
The patent also notes that by reducing the potential for structural damage, disaster resistant panels can reduce expenses related to insurance and reconstruction. In 2003, windstorms in the South and Midwest cost insurers about $5 billion, according to Insurance Journal. The most expensive U.S. natural disaster for the insurance industry, the 1994 Northridge earthquake in California, was estimated to have cost about $44 billion, according to the National Academy of Sciences.
The patent is the sixth approved on the basis of AEWC research since the 33,000-square foot center opened in 2000.