One year after Hurricane Katrina hit the Gulf Coast, engineers and designers are still studying measures to improve the durability of buildings. According to researchers for the Wind Engineering Research Center at Texas Tech University, concrete is a good bet–much better than wood and steel.
Jackie Craven of About.com explains the study:
To duplicate hurricane-like conditions in the laboratory, researchers shot wall sections with 15-pound 2 x 4 lumber “missiles” at up to 100 mph, simulating debris carried in a 250 mph wind. These conditions cover all but the most severe tornadoes. Hurricane wind speeds are less than the speeds modeled here.
Missile tests designed to demonstrate damage from hurricanes use a 9-pound missile traveling about 34 mph.
Researchers tested 4 x 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.
All the concrete wall systems survived the tests with no structural damage. Lightweight steel and wood stud walls, however, offered little or no resistance to the “missile.” The 2 x 4 ripped through them.
“The results of the tests were not surprising, but they were dramatic,” says Donn Thompson, PCA’s residential technology program manager. “Concrete walls meet both the criteria needed to protect occupants in a severe storm—structural integrity and missile shielding ability.”