NTSB: Bridge collapse caused by gusset plates, poor design

After more than 15 months of investigation, the National Transportation Safety Board began presenting their findings on the collapse of the Interstate 35W bridge at a two-day hearing that started Thursday. At the meeting in Washington, D.C., NTSB investigators said a major factor in the collapse of the bridge was the failure of gusset plates, which were not designed properly. Investigator Jim Wildey said the bridge was designed in such a way that if one portion failed, the rest of the bridge could potentially collapse. After the failure of the gusset plates at node U-10, the collapse of the bridge was unavoidable, he said. Wildey also ruled out other possibilities in the collapse, including corrosion damage, pre-existing cracking and the conditions of the bearings and piers. In his opening comments, Mark Rosenker, acting NTSB chairman, said every factor that may have played a role in the collapse has been examined. “We’ve done all we can to see that such a tragedy never, ever happens again,” he said. A number of the victims and family members were allowed at the hearing, while others affected by the collapse gathered at the St. Paul Armory downtown to watch a live webcast of the proceedings. A final ruling is expected near the end of Friday, when the NTSB will vote on final findings on the Aug. 1 bridge collapse that killed 13 people and injured 145. Check Friday’s Daily for more.