Piece reattached after coming loose in moderate wind before fatal concert

Source: Fox59

Inspectors searching for answers to the collapse of the main stage at the Hoosier Lottery Grandstands at the Indiana State Fair may be looking at a part of the stage roof that came loose in a moderate wind earlier in the week.

The stage collapsed in winds estimated above 70 miles per hour Saturday night, literally one minute before the start of a concert by the country band Sugarland. Five people died and 45 people were treated at local hospitals.

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According to sources, a center plug serves as a wind pressure release device on a canvas stage roof. The center plug from the front to the back of the stage and bridges the gap between the left and right stage skins, or large roof panels, that top the stage superstructure.

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Video of the stage collapse shows the center plug flying loose a split second before the left stage skin releases immediately before the stage begins to buckle and fall. A source tells Fox59 News that center plug is designed to come loose at wind speeds of approximately 20 miles per hour in order to relieve air pressure on the rest of the roof. Collapse video shows the center plug clearly holding in place until winds reached approximately 70 miles per hour even though concertgoers say the wind had been increasing in the minutes before the collapse.



Read more: http://www.fox59.com/news/wxin-grandstand-collapse-investigates-roof-fox59-investigates-condition-of-grandstands-roof-before-collapse-20110818,0,2486205.column

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Excellent slo mo video at link. Interested in comments by DU'ers who know about construction of structures like this and storms.

Sounds like the center plug worked correctly earlier in week, but not night of the collapse. Could it have been tightend down too tightly or incorrectly?

I used to build the type of stages that collapsed in Indianapolis last night.

They even discuss how sections of the canvas are supposed to come loose to relieve pressure during such a circumstance, IIRC.

PB

untrained local yokels to put together these complicated systems. Always trying to save a penny to the detriment of the public.