Video: Thornton Tomasetti Report

INDIANAPOLIS (WISH) - A maximum wind gust of 59 mph hit the stage that night, said Scott Nacheman, vice president for Thornton Tomasetti. The stage structure was built to withstand winds up to 25-43 mph depending on the wind direction.

"Gravity takes over and the structure ultimately fails," Nacheman said.

Despite questions from the general public, Nacheman said the blue tarp on top of the stage rigging did not contribute to the stage going down in August. The firm’s testing actually revealed that the structure was more vulnerable without the tarp.

"The structure was already failing by the time that that tarp released," Nacheman said.