Consultants URS are to be charged over the I35w bridge collapse, according to the lead attorney for the victims of the disaster
“We will now seek justice for our clients against the engineering firm (URS) our state had hired before the collapse to ensure the bridge was safe,” said Robins, Kaplan, Miller & Ciresi lawyer Chris Messerly. “They knew the roller bearings were frozen - it is in their own report. They knew that some of the 1/2 inch gusset plates were bent. We have pictures they took. They knew that the bridge design was obsolete and had no redundancy. Also, the weight placed on the bridge by the construction company (PCI) unquestionably substantially contributed to this catastrophe.”
The collapse of the I35W bridge in August 2007 killed 13 people and injured many more.
Investigators from the US National Transportation Safety Board (NTSB) found that gusset plates used to connect load bearing columns and trusses had inadequate load bearing capacity last year.
However according to attorney Chris Messerly, experts from engineering consultancy Thornton Tomasetti believe that the initiating event wasn’t the fracture of a key gusset plate in the bridge, but the failure of a horizontal beam.
Messerly said Thorton Tomasetti concluded that a chord buckled because of heat stress on the bridge that day, the weight of construction materials on it and frozen roller bearings that restricted the thermal movement of the bridge. This then caused the gusset plate to fail.
“There were a number of key factors that occurred on that day to initiate this failure,” said Messerly. “First, the roller bearings (which allow the bridge to expand and contract on the piers during our broad temperature swings of over 100 degrees) were rusted solid and would not move. As a result, the members (i.e., the L9-11 chord) were under tremendous stress. Also, the construction company working on the bridge chose to pile its construction materials on the bridge, which weighed as much as a 747. Another factor was the heat on the day of the collapse which forced the bridge to expand. All of these things led to the greatest man-made disaster in our state’s history.
“The reason it took TT so long to reach their conclusion is because it was not until very recently that our government (the NTSB) allowed them to see the final pieces of evidence,” said Messerly. TT has now seen all of the physical evidence and all of our state’s documentation and photographs of the bridge for years before the collapse.”