THE RESEARCH 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 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.
Reinforced concrete homes have proven their wind-resistance in the field during tornadoes and hurricanes. In Urbana, Illinois, a recently constructed insulating concrete form home withstood a 1996 tornado with minimal damage. In the Liberty City area of Miami, several concrete form homes survived Hurricane Andrew in 1992. In both cases, neighboring homes were destroyed.
Monolithic Domes, which are made of concrete and rebar, have proved especially strong. The sturdy concrete construction combined with the dome shape make these innovative homes nearly impervious to tornadoes, hurricanes, and earthquakes.
Want to build your home with concrete? You'll find house plans, illustrations, and lots of information at Concrete Homes, the Web site for the Portland Cement Association.
For help planning and constructing a Monolithic Dome home, visit the Monolithic Dome Institute.