Hundreds of roofs in the Northeast collapsed after a series of winter storms swept through the region from just before Christmas until the week after Groundhog Day, with minimal thawing in between. The accumulated loads proved more than many commercial flat-roof systems could handle. Photo: Courtesy Town Of Nottingham, N.H. Roof of Nottingham, N.H., town garage proved no match for series of winter storms. Injuries were minimal, but as the tally of structural failures mounted, some began to wonder whether it is time to re-examine building codes if the region is entering a climate-change cycle that will trigger increased precipitation
While a demolition contractor clears debris and stabilizes the site of what the owner claimed was the largest sloped green roof in North America, a forensics team is investigating why the structure suddenly collapsed on the afternoon of Feb. 13. Photo: Courtesy Aquascape Freeze-thaw cycle following major snowfall apparently triggered collapse of large green roof near Chicago. Related Links: Ice, Snow Take Toll on Northeast Roofs, But Engineers Say Codes Are Adequate The 700-ft by 50-ft area of roof that collapsed was attached to a warehouse. There were no injuries or inventory damage, said Ed Beaulieu, vice president at Aquascape,
Large pneumatic bags designed to contain blasts from improvised explosive devices are finding a peaceful application in Egypt, propping the crumbling interior of the nation’s oldest pyramid. When inflated, an array of the 1.5-meter-tall bags will allow workers safely to stabilize the fractured interior roof of the subterranean burial chamber, itself buried under the ancient stone heap that forms the Pyramid of Djoser, south of Cairo. Built nearly 4,900 years ago in the reign of Djoser, the first king of the Third dynasty, the structure is the world’s oldest major stone monument, according to Zahi Hawass, secretary general of Egypt’s
The U.S. Green Building Council says it is taking concerns about the exclusion of structural materials in the draft of the next version of its LEED green building rating system “very seriously.” Structural engineers are objecting to the absence of structural materials in credits for recycled content, regional materials and renewable materials, renamed bio-based materials in the draft. “It’s baffling to me,” says Mark Webster, a project manager with structural firm Simpson Gumpertz & Heger Inc., Boston, and chair of the working group on LEED within the sustainability committee of the American Society of Civil Engineers’ Structural Engineering Institute (SEI),
The Minneapolis Metrodome, whose air-supported roof split under the weight of more than 17 inches of snow and ice on Dec. 12, won’t see any action at least until after Christmas. Photo: AP/Wideworld Crew checks out damaged fabric from a platform. Four panels will be replaced. The Minnesota Vikings moved their Dec. 20 National Football League game with the Chicago Bears to the University of Minnesota’s TCF Bank Stadium. Other Metrodome events through Dec. 23 have been canceled as crews replace and repair the Teflon and fiberglass panels. Birdair Inc., Amherst, N.Y., which made and installed the roof, and Geiger
Photo: APimages/AN Heisenfelt The fabric roof of the Metrodome Stadium in Minneapolis collapsed on Dec. 12 under the weight of 17 or more inches of wet snow. Steve Maki, the stadium’s director of facilities and engineering, said a seven-person snow-removal crew retreated from the roof when winds gusting to 40 mph made working unsafe. Maki says that, early Sunday morning, one fabric roof panel gave way because of the snow load, which overstressed two more panels that also then failed. The roof was fabricated and installed by Birdair Inc., Amherst, N.Y., in 1981. Maki says three samples of roof fabric
Collaborative city greening is gaining international momentum, most recently with the signing of the Global Cities Covenant on Climate by more than 135 mayors attending the World Mayors Summit on Climate, held on Nov. 21 in Mexico City. Also at the summit, the World Mayors Council on Climate Change launched a web-based city climate registry, a mechanism for municipalities to ensure “transparency and accountability of local climate action,” according to the WMC. Related Links: Green Building Thrives in Shaky Economy Airports Push the Green Envelope The actions in Mexico City come on the heels of a Low-Carbon Cities for High-Quality
If U.S. jurisdictions adopt new, more restrictive model energy codes and standards, new buildings may end up using 20% to 30% less energy than existing structures. Late last month, members of the International Code Council voted to accept the 2012 International Energy Conservation Code for new residential and commercial buildings. Early this month, the American Society of Heating, Refrigerating and Air-Conditioning Engineers as well as the Illuminating Engineering Society of North America published ANSI/ASHRAE/IES Standard 90.1-2010. The standard, called Energy Standard for Buildings Except Low-Rise Buildings, provides minimum requirements for energy-efficient design. If followed, the standard could provide more than
The American Society of Civil Engineers unveiled details of a long-awaited sustainable infrastructure certification program during the group’s national conference on Oct. 21-23 in Las Vegas. Tailored to be broadly adaptable to particular circumstances, the program brings some 900 existing sector-specific rating systems under one umbrella. After successful case studies, the system called PRISM, or Project Rating for Infrastructure Sustainability and Management, will launch in May 2011. The voluntary rating system, developed by ASCE, the American Council of Engineering Companies and the American Public Works Association, aims to do for bridges, roads and waterways what the U.S. Green Building Council’s
The behavior of engineered structures in the magnitude-8.8 Maule earthquake that struck Chile on Feb. 27 is unlikely to lead to big changes in U.S. practice or codes, agree engineers. Photo: Ramon Gilsanz In Chile, apartment-unit doors jammed, trapping occupants, thanks to lightly reinforced link beams over openings. “The performance of modern engineered construction in the quake was quite good, and most instances of poor performance are associated with differences in Chilean and U.S. design practice,” said Ronald O. Hamburger at the 2010 National Council of Structural Engineers Associations conference, held from Sept. 30 to Oct. 2 in Jersey City,