Drivers on a Milwaukee Avenue bridge just north of Libertyville can't see what's below -- a pile of debris filled with hefty chunks of concrete that used to be part of the span.
The more than 23,000 motorists who drive over that bridge each day can't see the rusty, exposed support beams of the bridge. They don't notice tiny pieces falling from the bridge into the water below as cars pass overhead. They probably don't realize it's one of hundreds of bridges in the six-county Chicago and suburban area listed as "structurally deficient" in federal and state bridge inspection records.
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Inspectors list the Milwaukee Avenue bridge as being in "serious condition," but 11 bridges in the region are in even worse shape. Inspection reports show bridges in Lombard, Rolling Meadows, Warrenville and Villa Park are among those listed in "critical condition."
One of every 13 bridges in the six-county area is listed as structurally deficient, according to a Daily Herald analysis of data from the Federal Highway Administration and the Illinois Department of Transportation. Illinois is in better shape than most states, yet transportation officials say finite funding and construction timing will always keep some of the state's bridge inventory in shoddy condition.
At the same time, infrastructure experts worry bridges in the worst shape may not be first in line for funding even now, three years after the collapse of the I-35W bridge over the Mississippi River in Minnesota killed 13 people.
Fixing bridges is a priority, says Sarah Wilson, a bridge maintenance engineer for the Illinois Department of Transportation who says none of the bridges are unsafe for drivers. "As many as 20 projects (regionally) are under way," she said. "But there are bridges that are being brought on the (deficient) list as others are being taken off."
More than potholes
There are 293 structurally deficient bridges in the metropolitan region -- Cook, DuPage, Kane, Lake, McHenry and Will counties, according to the state and federal data. Those counties contain 3,691 bridges in all.
More than half of the deficient bridges -- 153 -- are in Cook County, 78 of them in the suburbs. Will County has 45 deficient bridges. Kane County is home to 27. DuPage County has 23. Lake County's tally is 23. And McHenry County holds 22.
Drivers can't always tell which bridges are bad. Potholes tell only a small part of the story. A bridge over Salt Creek in Rolling Meadows, for example, is barely noticed by drivers on busy Algonquin Road. But underneath, inspectors say, supports holding up the roadway are failing, resulting in the bridge's "critical" rating. The 39-year-old bridge is scheduled for replacement next year, state transportation officials said.
The Butterfield Road bridge over the West Branch of the DuPage River in Warrenville has similar defects. In Lombard, the Hill Avenue bridge over the East Branch of the DuPage River has deteriorating horizontal supports. The Ardmore Avenue bridge over railroad tracks in Villa Park is deficient in all inspection areas, state records show. All are listed as critical.
Deterioration of the bridge's roadway is the most common defect. The horizontal supports often wear out at the same rate as the roadway. Transportation experts say failing vertical supports can be the costliest defect to fix.
Significant defects to a bridge may not be noticeable to the naked eye, IDOT officials said. Structural issues may occur within the bridge and may not appear outwardly as a flaw, experts said. A fresh coat of paint on a deteriorating bridge can hide defects from the layman, but not bridge inspectors, engineers who either work on contract or as employees of transportation departments.
Bridges are rated in three areas on a scale of nine to zero, with nine being the best and a zero being so bad the bridge has been closed -- which hasn't happened in the six-county region, transit officials say.
Any time the bridge scores a four or lower on one or more of the three inspection areas, it goes on the deficient list, Wilson said. The lower the score, the more likely a bridge will receive funding for repairs or replacement.
The worst bridges in the suburbs -- including the examples in Rolling Meadows, Warrenville, Lombard and Villa Park -- score a two. Transportation authorities say even that doesn't indicate dangerous conditions, though heavy trucks might be banned.
"Just because a bridge is structurally deficient doesn't mean the bridge shouldn't be traveled on," said Nancy Singer, a Federal Highway Administration spokeswoman. "Those bridges should just be paid more attention to with more frequent inspections and use of load postings to reduce the amount of weight on the bridge. It doesn't mean it should be closed."
IDOT is responsible for maintaining most of Illinois' bridges. The Illinois State Toll Highway Authority, counties, townships, municipalities and other government agencies take care of the rest.
Some transit agencies do a worse job than others of maintaining those bridges. While one in 13 bridges is deficient overall, the analysis shows that one out of every seven bridges maintained by a municipality in the six-county area is deficient, or 15 percent of the 728 municipal bridges.
Making sure bridges in the worst condition receive priority funding should be the paramount concern, but infrastructure experts worry there's no way to make sure that's the case.
Components of the Hill Avenue bridge in Lombard, for example, have been in critical condition for years, said village engineer Dave Dratnol. Weight limits are posted to keep heavy trucks off the bridge, which is unlikely to be fixed before 2014. Meanwhile, a Golf Road bridge in Rolling Meadows was fixed this year, though it was in better condition than the Lombard bridge.
Money is one reason. Towns typically pay 20 percent of repair costs for bridges they control, with the rest in federal dollars.
"It's a matter of budget priorities," Dratnol said. "Routine maintenance gets performed, but when it gets to major expenditures of millions of dollar, that's not a simple line item in the budget."
A U.S. General Accounting Office study in July criticized the federal government for allowing bridges that weren't rated deficient to receive repair dollars.
IDOT officials say several factors merge with the inspection ratings to determine which bridges are first in line for repairs. Accident data, load limits and traffic volumes are considered. Some 52,000 cars use the Rolling Meadows bridge each day while 4,600 use the Lombard bridge daily, the reports indicate.
Experts say ratings also can vary among bridge inspectors, partly because of differences in how standards are applied and, some believe, because some inspectors emphasize a bridge's poor condition to reel in funding for repairs or replacement. That can make it difficult to know which bridges need attention first.
Though bridge inspectors take mandatory classes with a goal of consistent ratings, "it never works out that way," said John Frauenhoffer, a Champaign structural engineer who has inspected bridges across Illinois.
Inspectors "sometimes rate things for the purpose of gimmicking the funds," said Frauenhoffer, past president of Illinois Society of Professional Engineers.
"They have motivation to get a dire outcome because it puts the bridge higher on the priority list," added Joseph Schofer, director of the Infrastructure Technology Institute at Northwestern University in Evanston. "I don't think anyone is cheating, but the whole system is designed to score low."
IDOT spokesman Guy Tridgell disagrees, saying the inspectors' classes every five years and other processes make sure funding goes where the need is greatest.
"The work of inspectors is checked by the program manager," Tridgell said.
Bridge repair is a Sisyphean task.
Like the Greek myth of the impudent king spending eternity rolling a boulder uphill, the job of bringing bridges up to snuff never ends.
Transportation experts say it would take tens of billions of dollars to repair all 2,373 deficient bridges in Illinois, which ranks third highest in the nation for total number of bridges.
Illinois pays for bridge repairs and other transportation needs with a 19-cent tax on every gallon of gas sold in the state, plus receives a portion of the federal government's gasoline taxes. But that isn't enough: two recent state borrowing packages worth $5 billion went toward road and bridge improvements.
Yet, many states are worse off.
While 9 percent of Illinois' 26,263 bridges statewide are structurally deficient, the national average is 11.8 percent, according to the Federal Highway Administration's data.
Pennsylvania, with almost as many bridges as Illinois, has 27.2 percent listed as deficient, according to federal bridge inspection records.
Even before the Minnesota bridge collapse in 2007, Illinois had gradually begun to make progress in fixing deficient bridges, whittling those marked deficient down from 11.1 percent in 2000.
Minnesota's I-35 bridge had been rated structurally deficient in 1990, underwent repairs in 2001, and again was rated deficient in 2005, according to news reports. It was not set for major rebuilding until 2020.
After the collapse, gusset plates that were connected to bridge beams were deemed to be a half-inch thinner than they should have been, contributing to the disaster. But that wasn't the solitary cause.
"There were multiple causes associated with that, and it was an extraordinary failure," Schofer said. "It's like life: It's a bunch of little things."
In the aftermath, every agency in charge of maintaining bridges throughout Illinois was put on alert to inspect bridges again, focusing on points where the Minnesota bridge failed and on similar types of bridges.
"It was a truss (bridge) that failed," Wilson said. "So we did more in-depth inspection and analysis of our trusses to make sure the same type of failure couldn't occur here. We've got several bridges of that type, but one of the causes of the collapse was that it wasn't designed properly. And we also added an emphasis on inspection of the gusset."
Illinois transportation experts contend none of the bridges open to the public is dangerous.
"If we had a bridge that we considered unsafe, it would be closed," Wilson said. "We don't leave unsafe bridges open."
Breaking: 'We don't leave unsafe bridges open'