ChicagoRiver North

Link Bridge Chicago
The Outer Drive Bridge, also known as the Link Bridge, is a 1930s-era structure that is deemed “structurally deficient”
by the Illinois Department of Transportation. (Photo/Kelly McGowan)

Thousands of Illinois Bridges Graded 'Structurally Deficient’ 

By Kelly McGowan and Kevin Sherman
@RedLineProject

Posted: Thursday, Dec. 13, 2018

Thousands of Illinois bridges are structurally deficient, according to data gathered from the Federal Highway Administration and other studies.

Illinois also ranks fourth out of 50 states, Puerto Rico and the District of Columbia in the number of structurally deficient bridges, according to the FHA data compiled in 2017. The state also ranks fourth nationally with the number of bridges with 26,775.

Approximately 41 percent of Illinois’ bridges are classified as “fair,” 51 percent are in “good” condition, and about 8 percent are in “poor” condition.

According to the FHA, Cook County alone has 1,698 bridges – the greatest number of bridges in all of Illinois’ counties due to its large population and number of waterways. Of those bridges, 169 (10 percent) are deemed structurally deficient.

The Lake Shore Drive Outer Drive Bridge that spans the Chicago River holds more than 155,000 vehicles daily as reported by the Chicago Department of Transportation (CDOT). This bridge built in 1937 has seen little restoration since its opening. However, plans are underway to repair the bridge along with the Navy Pier Flyover bike path this year.


Infographic: The top 10 states with the most structurally deficient bridges in the U.S. 


For the past 20 years, the American Society of Civil Engineers has assessed America’s infrastructure. In 2017, ASCE released its quadrennial Infrastructure Report Card revealing that America received an overall infrastructure grade of a D-plus, and among the 16 categories graded, bridges received a C-plus.

Improvements are necessary to ensure safety, which requires renovating or replacing bridges, experts say. With each passing year, the number of structurally deficient bridges in Illinois has grown due to the infrequent inspection checks and age of the bridges in Cook County, according to the Illinois Department of Transportation.

 

What exactly does structurally deficient mean? Chicago Tribune transportation reporter Mary Wisniewski claims it does not necessarily mean that the bridge is about to collapse, but it is in need of repair and rebuilding. 

 

 

“If the bridge remains unrepaired for too long, it may have to be closed, or states may limit traffic on it," she said. "We can travel on these bridges, but there is a risk, depending on the quality of each state’s bridge inspection program. If a state’s inspection program is deficient in some manner, it may keep a bridge open that should be closed, which would pose a danger to the traveling public.”

The markers shown in the map are some of the structurally deficient bridges in Cook County, according to IDOT. The labels are defined by the overall structure evaluation of the bridge, meaning the average ratings of the deck, superstructure, and substructure. The ratings themselves are graded the same way, from 0-9.

All the red markers are bridges graded 0-4 overall, all the yellow markers have a 5-6 rating, and the green markers have a 7-9 rating. As shown in the map, there is only one structurally deficient bridge that is classified as “good” with a 7 rating shown in green.

There are no structurally deficient bridges in Cook County that are rated an 8 or 9, as expected. Most of the structurally deficient bridges in this county are rated as “poor.”

However, Illinois has not had an infrastructure plan since 2009, and the ASCE recommends that the state should prioritize their efforts in creating a new plan. Many pundits were optimistic before the 2018 midterms noting that after the elections, new infrastructure proposals were to follow.

Illinois Governor-elect J.B. Pritzker has said he wants to make an infrastructure capital bill, and several sources, according to Wisniewski, have told her that the state should expect a bill as early as next year.

Navy Pier Flyover Bridge

Navy Pier Flyover bridge project for bikes and pedestrians
is scheduled to be completed before 2019. (Photo/Kelly McGowan)

Mayor Rahm Emanuel is using his clout in his remaining months in office to push for one as well. The stipulation on how to fund such plans are likely to be what halts such passage, according to several reports.

On a state level, Pritzker has offered several ideas on how to find new sources of revenue. He has named expanding gambling as a possible source of revenue, as well as taxes obtained from legalizing marijuana. The Civic Federation has warned against this kind of “gimmick” to fund a capital bill. Instead, the organization recommends a change in the income tax, as well as an increase in the gas tax, which has not been raised in 27 years.

The procedures for evaluating bridges has been the same for too long, says Dr. Didem Ozevin, a professor and researcher in Civil Engineering at the University of Illinois at Chicago (UIC). Currently, evaluations of bridges are done in-person by visually inspecting the structure’s health. Those who inspect bridges are trained specialists, however, there are always possibilities for human error.

Back in 2006, Ozevin, along with her department, hosted a workshop called “Evaluation of Bridge Inspections and Assessment” where they welcomed inspectors, engineers, and contractors to discuss ideas on how to better inspect these bridges.

One idea shared included drones with cameras to reach places that workers cannot. Another study investigated new types of sensors that use optic fibers to monitor bridges. Such an innovation would allow transportation agencies to watch bridges in real-time.

UIC's Alex Przybycin commutes to campus along with 85 percent of his classmates. To get to school each day, Przybycin uses Lake Shore Drive, and crosses Outer Drive Bridge. When told that the bridge is deemed structurally deficient, he said “that does not surprise me at all. You do not even have to get out of your car to see how bad the bridge’s conditions are.”

 


Cook County Bridge Inspections

CDOT is responsible for inspecting bridges in Cook County. Bridges are graded based on various categories: the most important categories being inspected are “Deck,” “Superstructure” and “Substructure.”

The graphic below shows exactly what these three categories are being evaluated for, and what they are rated, ranging from 0-9 on the National Bridge Inventory (NBI) scale; 0 being named as failed condition and 9 being in excellent condition. These numbers also coincide with names such as “good,” “fair,” and “poor.” The data on these bridges are gathered from an inspection in 2017.

 

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