May 6, 2008 5:37 pm US/Central
MnDOT To Close Part Of Duluth Bridge To Fix Gussets
DULUTH, Minn. (AP) ―
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John Bray, special assistant to the district engineer, said the bridge isn't in peril, but said the gusset plates have thinned over time. (File)
AP
Minnesota transportation officials on Tuesday announced a partial closing of the Blatnik Bridge that connects Duluth and Superior, Wis., after finding that gusset plates at eight spots on the bridge didn't meet load requirements.
Traffic on the bridge will be reduced from four lanes to two while the plates are reinforced, with work expected to be complete by the middle of June.
"The point to stress is that the bridge is safe," said Mike Robinson, district engineer for the Minnesota Department of Transportation. "By reducing it to two lanes, the live loads on the bridge are substantially reduced."
The bridge, also known as the High Bridge, opened in 1961. Reconstruction from 1992 to 1994 added a new, thicker deck and heavier railings, and an analysis found that the gussets weren't sufficient for the added weight, MnDOT said.
The gussets -- 16 in all -- will be reinforced with angle irons. The L-shaped pieces of metal will be both bolted and riveted on in what state Bridge Engineer Dan Dorgan called "a rather simple fix."
The bridge, which carries I-535 over the St. Louis River, carries about 29,500 vehicles a day, MnDOT said. A fact sheet said the bridge is the state's second-longest at 7,980 feet.
Minnesota's bridges have been under close scrutiny since the Minneapolis bridge collapse in August, a catastrophe blamed in part on too-thin gusset plates. The partial Blatnik closure comes just a few weeks after the DeSoto bridge in St. Cloud was shut down because of warped gusset plates.
Both problems were found as a result of special inspections ordered up by Gov. Tim Pawlenty in the wake of the Minneapolis collapse. The DeSoto bridge has remained closed, and MnDOT decided to replace it rather than try to repair the gussets.
Rep. Jim Oberstar, the Minnesota Democrat whose district includes Duluth, said the partial closure showed the state "is taking the proper steps" to ensure public safety.
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The original I-35W bridge over the Mississippi River opened in November 1967 and was 1,907 feet in length. The replacement bridge opened in September 2008 and measures 1,216 feet in length.
(© 2009 CBS Broadcasting Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)
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