Repairs to I-80 span get under way Friday

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By Tom Saul | Thursday, July 24, 2008 9:42 PM CDT | () comments

Crews expect to start temporary repairs on the Interstate 80 bridge at LeClaire Friday, but it could be weeks before permanent repairs are completed and the two outside lanes are reopened.

The inside lanes on the north- and southbound spans are still safe to drive on as long as drivers obey signs and do not stray into closed areas, said Ralph Anderson, bridge engineer for the Illinois Department of Transportation.

In the meantime, trucks with over-sized loads or that require permits to carry heavier than normal cargos have been barred from the bridge and are being redirected to the Interstate 280 bridge, said John Wegmeyer, a program implementation engineer for the Illinois DOT, District 2, which serves 10 counties in the northwest part of the state, including Rock Island County.

Signs on the interstate system will warn truck drivers of conditions on the I-80 bridge, Wegmeyer said.

Permanent repairs will involve cutting out cracked portions of support beams, called “stringers,” beneath the outer lanes of the bridge decks and bolting in place new sections of steel, Anderson said.

There are 12 cracks, all visible to the naked eye, that resulted from corrosion from snow melt and salt and metal fatigue caused by repeated use of the twin spans by heavy truck traffic, Anderson said.

The cracks are near expansion joints in the bridge decks, Anderson said. Shaping of the ends of some stringers was also done incorrectly during work in 1995 to replace the bridge surfaces and may have contributed to the cracking. The bridge opened in 1966.

“There is a slope on the deck that lets the snow get pushed to the outside during the winter, and it sits there longer and combines with the road salt and melts and seeps through the expansion joints,” Anderson said. “Heavy truck traffic also tends to use the outside lanes and, over time, all that repetition causes fatigue.”

The cracks were discovered Wednesday as a joint inspection crew for the Iowa and Illinois DOTs walked the bridge, said Dena Gray-Fisher, a spokeswoman for the Iowa agency. Earlier in the week, an Iowa crew inspected the Interstate 74 bridge and found no significant problems, she said.

The I-80 inspection had a different result.

“They noticed a slight depression in one of the outside lanes, and that told them something was not right,” Anderson said of the inspection. “They are trained to know what to look for, and when they went underneath, they could see the cracking.”

The I-80 bridge carries 30,300 vehicles per day, according to Illinois DOT figures. Nearly one-third of those, or 9,800 of the vehicles, are trucks. It is the second most heavily traveled Mississippi River-crossing bridge in the Quad-Cities after the I-74 span, which is used by 70,800 vehicles per day.

The bridge was last inspected a year ago and no significant problems were found, Anderson said. But, all metal and concrete spans are subject to damage from corrosion and fatigue from repeated heavy use.

Anderson called the inspection and the closing the lanes “proactive,” a move meant to deal with the cracking as soon as it was found.

“As soon as we became aware of it, we jumped on it,” he said.

Gena McCullough, of the Bi-State Regional Planning Commission, said she doesn’t anticipate major traffic tie-ups as a result of the lane closures. Most of the drivers who use the I-80 bridge are traveling through the area with no plans to stop.

A portion of I-80 at its intersection with Interstate 88 south of the span is already closed for repairs to another bridge, and it hasn’t result in traffic congestion, Wegmeyer said.

“If we end up with back-ups, there are plans to handle them, but we don’t want to do anything yet because of everything that is going on this weekend with the Bix and the RAGBRAI,” Wegmeyer said of events scheduled in Davenport and LeClaire. “We don’t anticipate any problems.”

Tom Saul can be contacted at (563) 383-2453 or tsaul@qctimes.com.