A design flaw and the use of the wrong type of steel is to blame for the collapse of a section of concrete floor last year at the David L. Lawrence Convention Center in Pittsburgh, according to a report released Feb. 4.
A large slab of concrete gave way under the weight of a tractor-trailer in the loading area of the center on Feb. 5, 2007, according to a report by the Associated Press. No one was injured, but the center remained closed for more than a month.
An engineering firm hired to investigate the collapse, Wiss, Janney, Elstner Associates, said a slotted bolt connection used to attach a support beam to an expansion joint was inappropriate given the friction that would develop with temperature changes, according to the AP. The Pittsburgh-Allegheny County Sports & Exhibition Authority said it is asking for a combined $2 million from designer Rafael Vinoly Architects and steel contractor ADF International. The collapse cost about $4 million to repair, with half of that amount covered by insurance.