Tensile Roof Held Strong

When a tornado touched down in Atlanta, GA this past March, the Georgia Dome escaped major damage. Part of this was due to the presence of a tensile roofing system on the facility.

Inspections revealed that the Georgia Dome survived relatively unscathed after undergoing what Carl Atkins, general manager there, called a "focused Herculean team effort" by Birdair Inc., the specialty roofing contractor for lightweight long-span roofing systems and other tensile structures that that constructed the original roof on the Georgia Dome. Birdair's PTFE fiberglass fabric membrane envelops the structure.

During a Southeastern Conference (SEC) basketball game on the night of Friday, March 14, the Georgia Dome felt the effects of the 100-plus mph winds that struck Atlanta. The scoreboard swayed from the force exerted on the building, but none of the fans inside were injured. Designed to be flexible, the fabric roof rippled and bellowed with the wind but sustained only minor damage.

The storm, initially classified as a thunderstorm with winds in excess of 60 mph, was later upgraded. "The storm that hit Atlanta was a tornado," said AccuWeather's Ed Adams, manager of forensic services. "Its classification as an EF2 tornado means that winds in excess of 100 mph swept through the region."

CNN, which itself sustained heavy damage at its Atlanta headquarters, reported that The National Weather Service's Peachtree City office rated the storm an EF-2 on the Enhanced Fujita scale, meaning it packed top winds of 135 miles per hour. Both the Georgia's governor and Atlanta's mayor declared the city in a state of emergency.

Upon inspection of the Georgia Dome after the event, Birdair officials noted that, on the west side of the building, a diamond panel, a small sub-panel, and some cabling needed replacement. "The remainder of the roof is in very good condition, as we've established this through a thorough inspection of the membranes and attachments," said Dave Ricci, director of customer service and warranty at Birdair, Inc. "All involved at the Dome are very impressed with its performance. Buildings and other facilities around the dome suffered far greater damage, and the two panels that were damaged on the Georgia Dome were in the direct path of the tornado."

The game, being played with 18,000 people in attendance, was briefly delayed when the tornado struck at 9:40 p.m. The Washington Post later quoted SEC associate commissioner Charles Bloom as saying there were no injuries inside the arena among the fans, players and media attending the game between Alabama and Mississippi State. Within an hour the building was reported to be structurally sound and the teams finished the game. (Still, following the weather event, all events at Georgia Dome were cancelled for that weekend to ensure the safety and security of occupants.)

The Georgia Dome did not get hit directly, as tests indicate that the tornado itself passed about 100 yards north of the Georgia Dome. However, "the structure was definitely affected by the 100 mph winds," says Adams, general manager.

The tornado is the first to strike downtown Atlanta on record.