The upgrade of Interstate 74 is reportedly the largest road reconstruction ever in downstate Illinois.

The massive scope of the $460 million project has already resulted in more than a year's work on the artery through the Peoria area, even though lane reconstruction is not scheduled to start until April.

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For instance, 42 bridges that cross the expressway are to be rebuilt and in some cases widened for reasons that include an expected increase in motorists using alternate routes to avoid the mainline construction area, said Matt Jereb, construction engineer for District 4 of the Illinois Department of Transportation, the agency overseeing the project.

In the spring, eastbound traffic will be shifted into the westbound lanes, and barriers will be put in to separate the two streams of traffic, he said.

The Murray Baker Bridge, which carries I-74 traffic across the Illinois River, will also be shut for improvements between April and October. Traffic will be shifted to the south, where the Bob Michel Bridge and two others are located, or motorists can use the McClugage Bridge on the north to get into downtown.

In summer 2005, when the westbound I-74 lanes are reconstructed, traffic will be shifted to the east side.

"Trying to get word out to the public so they know what is happening and when closures are going to happen" was important, Jereb said.

Initiatives include posting information about the project on the Internet, setting up a weekly e-mail alert and hiring a consulting firm to assist in answering questions from residents and the media.

Communication to businesses and other entities has also been constant, Ryan said.

For example, the IDOT resident engineer talks to contacts at the OSF St. Francis Medical Center downtown to allay concerns about construction at the nearby Knoxville Avenue interchange. Because patient-carrying helicopters land at the hospital every day, flags were placed atop cranes and lights illuminate the machines at night.

Utility Help

Other major initiatives were done to prepare the way for the reconstruction, including the installation of new storm sewers.

Water collection will increase because the amount of road space is going up. The lane number in each direction on the interstate will go from two to three, and some city streets and bridges are being widened.

Two years ago, a trunk line to the river was installed, said George Ryan, project implementation engineer for IDOT. The trunk line will connect to auxiliary sewers adjacent to roads.

The trunk line can handle a big flush of water because it is made up of 78-in. pipes. "It is a big honker," Ryan added.

A by-product of the sewer installation is the relocation of hundreds of individual utility lines. Repositionings are also needed due to the installation of retaining wall and abutments on widened streets.

The utility relocations were done to ensure services - sewer, telecommunications, electrical, natural gas, water - are not interrupted, Ryan said.

In most cases, a new line was built while the one to be replaced was kept in service.
The only time a brief shutdown occurred was when the switch was made.

The most cumbersome switches were for telecommunications lines because of the Peoria's expanse and heavy usage of the Internet.

Utility relocations began in 2001 - two years before the start of the first stage of reconstruction - to make sure they were complete on time.

"We had people out every day to make sure relocations were going as they should," Ryan said. He added that during relocation, workers also found lines "we didn't know were there."

Aged Interstate

I-74's age and increasing traffic were key factors driving the thoroughfare's reconstruction.

About 45 lane mi. will be removed and replaced between Peoria and East Peoria, twin cities across the Illinois River from each other, IDOT's Jereb said. The construction zone forms almost an S shape.

About 30,000 vehicles traveled the highway every day when it originally opened in 1959, and the figure has doubled due to Peoria's growth.

The pavement has become worn from the heavy use, and motorists' safety is increasingly at risk. In fact, 13 of 22 areas of I-74 being reconstructed exceed the statewide average accident rate in a state with a major metropolis like Chicago.

I-74's Adams Street entrance ramp is particularly hazardous because it exceeds the statewide rate by 16 times, Ryan said.

"We are going to re-establish that access," he added. Every other ramp on I-74 will also be rebuilt.

There are related project elements, such as the widening of Sterling Avenue on the project's north reach from four to six lanes because the street feeds the Westlake Shopping Center and North Woods Mall, Jereb said. Spalding Avenue, an important downtown street near OSF Saint Francis Medical Center, will also be widened.

The Forrest Hill Bridge, also on the project's north, was widened during the preparation stage, and the city is enlarging the thoroughfare from two to four lanes.

Despite its name, I-74 precedes the interstate system. It was originally constructed to improve traffic flow between the twin cities and represents an important economic lifeline in Central Illinois.

"I-74 is a huge attribute to this community," Ryan said. "Caterpillar [Inc.'s] world headquarters is here. If I-74 wasn't here, do you think that would be here?"

Project's Varied Tasks

The variety of work to upgrade I-74 is extensive.

Bridge deterioration is so advanced that the bottom mats of some decks are exposed, Jereb said. Replacement bridges will be entirely new, including abutments, piers and the bridge itself.

An added touch is limestone facing on the abutments will make them a little more pleasant to look at than predecessor structures.

Twelve bridges have been rebuilt on the contract currently under way, and "several thousand feet" of abutments or mechanically stabilized earth wall have been installed for strength, said Aaron Tubbs, project manager for Chicago-based Walsh Construction Co., a general contractor on the project.

Excavating was necessary to create a cavity for the wall.

Other bridges are being redone in part to accommodate ramps that will be longer than previous ones for motorist safety, Jereb said.

"We have some bridges to allow entrance onto and off of I-74 at the same position, but at the same time not have the weaving [look] they have now," he added.

Indeed, design elements were incorporated to improve traffic flow and safety.

For instance, some feeder ramps in busy areas will have two lanes, and the design called for an auxiliary lane in those areas on the interstate.

"These auxiliary lanes between interchanges give traffic that wants to get onto the interstate extra room to merge into the other traffic and gives traffic that wants to get off the interstate extra room to get off," IDOT's Ryan said.

Structures will be built to encircle two ramps in the downtown area to create a tunnel for motorist safety.

The interstate lanes will be sturdy. Jereb said they will contain 11.5 in. of continuously reinforced concrete.

"The contractor has not approached us with putting a batch plant in," he added. "If they do propose that for stage two or stage three, we will explore it."