New transportation tax hike should speed bridge replacement

Bob McFarlin and Dan Dorgan
Bob McFarlin and Dan Dorgan brief reporters on MnDOT's plans for the now closed DeSoto bridge in St. Cloud.
MPR Photo/Tom Scheck

The state is looking at the fastest way to rebuild the Highway 23 bridge, according to MnDOT's Acting Commissioner Bob McFarlin.

The bridge was slated to be replaced in 2015, but MnDot was trying to move up that date even before Thursday's inspection. Now that the bridge is closed, MnDot is trying to accelerate the project even more, McFarlin said.

"It's not at all clear, one, whether any repairs are possible or two, whether there were any repairs possible, if it would be a smart thing to do in the meantime before replacing the bridge," McFarlin said.

MnDOT closed the bridge after inspectors noticed that four of the gusset plates were bowing a quarter of an inch. Gusset plates hold the steel girders of a bridge together.

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Dan Dorgan
Dan Dorgan, bridge engineer for MnDOT, discusses the closure of the DeSoto bridge in St. Cloud.
MPR Photo/Tom Scheck

The gusset plates may have been bending, because the bridge was carrying too much weight, MnDOT's Highway bridge engineer Dan Dorgan said.

MnDot engineers are meeting with bridge experts at the University of Minnesota to try to determine whether appropriate repairs can be made.

The problem is that it's not easy to replace the gusset plates in question. Crews would have to disassemble the entire bridge to replace the gussets.

One potential option is to see whether engineers can install reinforcing steel on the bending gussets, Dorgan said.

"The best analogy I can come up with for folks to think about there, is similar to one might have a brace on a leg, to stiffen that if one has a weak leg," Dorgan said.

MnDOT is in the process of reviewing the 59 bridges in Minnesota similar in design to the I-35W bridge that collapsed in August, 2007.

The National Transportation Safety Board suggested in January that gusset plates may have contributed to that collapse.

Following that announcement, MnDOT inspectors started reviewing the shop drawings on those 59 Minnesota bridges. Field reviews, like the one that prompted the closure of the St. Cloud bridge, are still underway.

Dorgan couldn't say which bridges still needed field reviews but he expects the entire review to be done by June.

One factor that won't have to be considered in the bridge replacement is money.

The Legislature passed a transportation package earlier this session that pumps billions of dollars into highway and bridge construction and maintenance. The funding comes from a gas tax increase and a metrowide sales tax increase.

MnDOT should have no problem financing the replacement of the St. Cloud bridge or any other bridge, according to Sen. Steve Murphy, DFL-Red Wing.

"Because of the bill that we passed and overrode the governor's veto on, the money's on the table now," Murphy said. "So if they decide that they need a brand new bridge, they'll get busy and get it designed and get it changed out."

MnDOT officials project that replacing the St.Cloud bridge would cost about $30 million. They said it could take up to four years under normal circumstances to replace the bridge.

MnDOT should replace the bridge quickly and not drag out the process, according to St. Cloud Mayor Dave Kleis.

The six block rerouting of traffic did not cause any significant delays on Friday, Kleis said, but he warned that traffic was light because many people were off work, observing Good Friday.

"The true test will be obviously on Monday when everybody is back to work and it won't be a holiday. It's a significant amount of traffic on that bridge on a normal day. Over 31,000 cars daily travel through there. It is probably the main artery through town in an east and west direction," said Kleis.

Kleis, Sen. Murphy and Gov. Pawlenty all praised MnDOT for its decision to close the bridge.