The National Transportation Safety Board (NTSB) told the media yesterday that the I35W bridge collapse was due to faulty gusset plates and heavy maintenance equipment on the bridge. Period.
Investigators say nearly 300 tons of construction materials on the bridge “played a role” in the tragedy and there is “no basis” to believe corrosion or other maintenance issues were a factor, according to internal NTSB deliberations.
I’m not convinced when it comes to “other maintenance issues.” If it is true that there was evidence in the file four years prior to the collapse that bridge gusset plates were bent, as the Strib asserted this weekend with some pretty compelling photographic evidence, the NTSB’s conclusions are dangerously incomplete.
Those photos in the file appear to be evidence of two things 1) faulty plates and 2) safety inspectors’ failure to identify and/or address faulty plates. When it comes to important lessons moving forward, the latter finding is every bit as relevant as the former.
(Note: MnDOT cautions against concluding that the Minneapolis bridge plates were warped, because no measurements were ever taken. It strikes me that inspectors who saw those photos, should have checked them out. Maybe it was some kind of wacky optical illusion, but someone looking at photos like that should have followed up with measurement equipment. And the fact that warped gusset plates have been found on the similarly designed St. Cloud bridge leads me to think that the photos may very well show what they appear to show, and this is not some irresponsible conspiracy theory.)
The NTSB needs to determine why the warped gusset plate photographs were not acted on. What they learn could increase the chance that future inspectors will handle the situation the way they are with the St. Cloud bridge in 2008 (i.e. closing it down when they see signs of danger), rather than how they seem to have handled it with the Minneapolis bridge when they enountered the warped gusset plate photos back in 2003.
This investigation is dispiriting. The NTSB, Legislature, MnDOT and Governor should be learning, not blaming or spinning.