A federal report released Tuesday on the collapse of the Dallas Cowboys’ practice facility suggested that the structure should have been able to withstand winds stronger than those that hit the building May 2 when it toppled, injuring 12 people, including paralyzing one and brain damage to another.
The National Institute of Standards and Technology found that the structure was hit by 55- to 65-mph winds and should have been able to handle winds of up to 90 mph.
The report suggested the following sequence of events at the time of the collapse, based on the weather conditions at that time:
•Buckling of the inner chord (inner side of the roof truss) of a frame in a section of the roof on the east side resulted in the formation of a kink in the frame.
•Failures of the east and west "knees" (connections between the side walls and the roof) allowed the frame to sway eastward with the wind.
•Compressive failure of the east side at the roof’s highest point (ridge) led to fractures of the nearby inner and outer chords in the vicinity of the ridge.
•A progression of frame failures throughout the structure resulted in total structural collapse.
As a result of the study, the National Institute of Standards and Technology is recommended that similar structures be evaluated for similar safety concerns.
"As a result of our findings, NIST is recommending that fabric-covered steel frame structures be evaluated to ensure the adequate performance of the structural framing system under design wind loads," said John Gross, study leader for the federal agency.
"It confirms what we suspected all along, that it was a dramatically underdesigned structure," he said. "There are a number of other large fabric structures that are supported by steel. I think Texas A&M has a practice facility and WinStar casinos has one of these. If I owned one of these structures, the first thing I’d want is a good structural engineer evaluating this report and my building." (Click here to read the entire article.)
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