5 Years Later: The Safety Of Minn.’s Bridges
MINNEAPOLIS (WCCO) – A lot has changed in Minnesota since the 35W bridge went down five years ago.
State lawmakers ordered emergency inspections of every bridge in Minnesota immediately afterward, and they did find some problems. And bridge technology is has become much more advanced than ever before.
After the 35W bridge catastrophe, state inspectors found 171 Minnesota bridges structurally deficient, or fracture critical — that means one major failure could cause safety issues.
But the state’s new bridge inspector says every Minnesota bridge is safe.
“Bridges could be structurally deficient, or fracture critical, or both, and still be safe,” said Nancy Daubenberger, Minnesota State Bridge Engineer. “In fact, bridges on our system are safe. And we’re working very hard to make improvements in the way of bridge safety since the 35W bridge collapse.”
Now, a 10-year, $2.5 billion effort to fix the bridges is nearly halfway done. Between 2008 and 2012, 65 were repaired or replaced, and 12 will be fixed by the end of the year. Sixty-five are ready for work beginning next year.
And since the 35W bridge collapse, the state has doubled the number of bridge inspectors from 55 to 110.
The Minnesota Transportation Alliance had been warning lawmakers about crumbling roads and bridges for years — the 35W collapse didn’t change that.
It says the state is still not facing up to future costs of keeping roads and bridges safe.
“Beyond 2018, there is another wave of bridges that will become deficient and we don’t have the money to fix those bridges,” said Margaret Donahoe, executive director at Minnesota Transportation Alliance. “So we don’t know how we will deal with those deficient bridges.”
The state now has advanced bridge monitoring equipment that can detect movement, cracks, and stress, and there are new limits on how much equipment and weight can go on a bridge.
Mark Rosenker said he can’t believe how fast the five years have gone since the collapse.
“It just seems to me almost like yesterday. This was such a tragic accident,” he told WCCO Radio’s John Williams Wednesday.
Rosenker was chairman of the National Transportation Safety Board that led the investigation into the bridge collapse.
He says the tragedy changed the way engineers and inspectors looked at gusset plates, the steel plates that hold beams together on truss bridges. Cracked and weakened plates were blamed for causing the bridge to fail.
Rosenker says it changed the way that bridges are designed and inspected. He says at the time, they didn’t have the right information about gusset plates that could have prevented the collapse.
“It was a lack of knowledge. It was frankly a lack of oversight from the company itself and its quality control that designed this bridge,” Rosenker said. “They didn’t do the right calculations on the gusset plates. They did it everywhere else.”