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05/05/2005: Concrete Construction
US News Wire had this article on Concrete Construction and Tornado Safety:”The month of May has the dubious distinction of being the most active tornado month. According to the National Weather Service, the record was set in May 2003, with 543 confirmed tornadoes. The most inherent danger to people and property during tornadoes is the debris carried in the high winds. Enter concrete homes.
Tests comparing the impact resistance of residential concrete wall construction to conventionally framed walls reveal that that concrete homes have the strength and mass to resist the impact of wind driven debris.
To duplicate tornado-like conditions, researchers at the Wind Science and Engineering Research Center at Texas Tech University shot wall sections in a laboratory with 15-pound 2 x 4 lumber "missiles" at up to 100 mph, simulating debris carried in a 250-mph wind.
This testing covered the maximum wind speed generated in 99 percent of U.S. tornadoes. Wind speeds are less than 150 miles per hour in 90 percent of tornadoes.
Researchers tested 4-by-4-foot sections of concrete block, several types of insulating concrete forms, steel studs, and wood studs to rate performance in high winds. The sections were finished as they would be in a completed home: drywall, fiberglass batt insulation, plywood sheathing, and exterior finishes of vinyl siding, clay brick, or stucco.
The concrete wall systems suffered no structural damage during the tests. However, the lightweight steel and wood stud walls offered little or no resistance. In some instances, the debris "missile" perforated completely through the wall.
Concrete homes meet both of the criteria needed to protect occupants in a deadly tornado-structural integrity and missile shielding ability.”
Having grown up in a “concrete house” (the plans for my childhood Park Ridge home came from Florida…hence the concrete under-structure with a brick façade and slate roof) I can say it was built like a brick bomb-shelter. It even had a special tornado/hurricane shelter in the basement. It was a SOLID house, even with six kids running, jumping and rampaging around all those years. But they sure don’t build ‘em like they used to…
Karen on 05.05.05 @ 05:20 AM CST
