The loss of life in a tragedy is always hard to take, but it stings even more when that tragedy could have been prevented.
The Interstate 35W bridge collapse in August 2007 claimed the lives of 13 people and injured more than 100 others. Now we find, in a two-day hearing on the National Transportation Safety Board's investigation of the collapse, that it was primarily due to design flaws. Gusset plates, which form a major structural support, were designed at a half-inch thick when they should have been at least an inch thick.
But while the blame goes to bridge designers, state and federal inspectors failed to see that the thinner gusset plates posed a problem. Inspectors glossed over them even though they could be seen inordinately bending on visual inspection.
Still, 40 years went by with no tragedy. The NTSB hearing proffered that the several hundred added tons of construction equipment and materials on the bridge bed - it was under repairs at the time - served as the straw that broke the camel's back.
If there is a lesson to be learned from this, it is to take steps to prevent such conditions from ever bringing down another bridge. Among NTSB recommendations is for a nationwide bridge design quality assurance program.
The final NTSB report will call for new federal and state inspection standards and review procedures of bridge designs, including gusset plates. The report will also call for greater attention to be paid to the effects of rust and corrosion on the structural integrity of bridges.
It's sad that it often takes a tragedy to spur action. But hopefully we have learned from this tragedy and will enact measures to ensure the safety of the traveling public.
- Pioneer of Bemidji
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