Out of the ordinary

Bridges Article June 09, 2009
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A crack has created a break in the routine for Illinois Department of Transportation bridge inspectors.

An annual checkup of the I-80 bridge, which reaches across the Mississippi River near the Quad Cities, revealed a crack in one of the floor beams holding the eastbound lanes. After officials closed the damaged portion to conduct a more thorough inspection, another crack was found.

“We found some deterioration in the joints,” George Ryan, Region 2 deputy director of highways for IDOT, told ROADS & BRIDGES. “IDOT’s main concern has always been and will continue to be safety, so we have shut down the eastbound lanes because we are concerned about safety.”

At press time, there was not a definite date as to when the bridge may be reopened. Conflicting reports ranged from the span being fully operational in a matter of weeks to several months.

Ryan told ROADS & BRIDGES that IDOT would be taking a hard look at past inspection reports as well as conducting more examinations to look at locations with similar connections in the coming weeks.

When all of the information is gathered, a repair plan will be put into action. IDOT was conducting annual inspections of the I-80 bridge, but have reduced that down to six months. Once the structure is repaired properly, IDOT will make the determination to keep them biannually or push them back up to yearly.

“Since we are still in the information-gathering portion of this we really do not have a timeframe [of opening the bridge],” said Ryan. “We want to safely open the bridge as soon as we can, but we are going to have to prepare plans and do some level of improvement before we can open the bridge.”

IDOT officials believe stress and fatigue are the major causes of the cracks. The I-80 bridge, which was constructed in 1966, handles 30,000 cars and trucks daily. Ryan also indicated that the construction method used over 40 years ago also might have been a contributing factor.

“It had some welds on it that we probably would not do today because we understand more about welds and how they cause stresses and can cause fatigue,” he said.

I-80 is experiencing major reconstruction this spring. Pavement is being ripped up for a 6½-mile stretch, starting at the bridge and going south. Traffic was moving on two of the four lanes of the bridge prior to the crack’s discovery. After the shutdown of the eastbound lanes, motorists were left to use one westbound lane.

Before the incident, the I-80 bridge was on the state’s repair list, but Ryan said their was the possibility of combining the contracts of the planned work with the emergency work.

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