NTSB chief backs statement on Minneapolis bridge flaw
The chairman of the National Transportation Safety Board is defending his decision to call an engineering flaw a “critical factor” in the collapse of the Minneapolis bridge that killed 13 persons and injured 145 others last summer.
Mr. Oberstar has said the NTSB’s Jan. 15 announcement that poorly designed steel plates played a role in the Interstate 35W collapse was “highly inappropriate” because the agency hasn’t concluded its investigation.
“Although there is no reason to believe that any other bridge in the country has a design error of this magnitude, we do not want to proceed under such a hopeful assumption,” Mr. Rosenker said in a letter to Mr. Oberstar yesterday.
“He seemed to get the message [Mr. Oberstar] was trying to convey,” he said.
Sixteen of the bridge’s 224 so-called gusset plates, which help connect steel beams supporting the bridge, were designed too thin, according to the NTSB. There are more than 400 steel-truss bridges similar to the I-35W collapse across the country, though Mr. Rosenker said he doesn’t think gusset plate design errors are a systemic problem.
In his Jan. 23 letter to Mr. Rosenker, Mr. Oberstar said he was concerned that the announcement could undermine the NTSB’s investigation and “create the potential for committing the board to conclusions which will be difficult to change if the subsequent investigation suggests other possible conclusions.”
“Please be assured that it was not my intent to get ahead of the ongoing NTSB investigation or to hypothesize about the root and contributing causes of the bridge collapse,” he wrote.