US Bridges

6th ST / Bl 55 (nb over I-55 (sb)

Fair

Sangamon County, Illinois · .25M S I-72 · Structure no. 084002800000000

Built
1963
62 years old, rebuilt 2009
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
282 ft
3 main spans
Daily traffic
10,500
2023 count
Owner
State
State Highway Agency

About this bridge

6th ST / Bl 55 (nb over I-55 (sb) is a steel continuous stringer/multi-beam or girder carrying 6th ST / Bl 55 (nb over I-55 (sb) in Sangamon County, Illinois. It was built in 1963 and reconstructed in 2009, so it is 62 years old, older than the Illinois average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 10,500 vehicles a day, roughly 5% of them trucks, projected to reach 7,929 by 2046. The structure is 282 ft (85.9 m) long and 37 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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Carries6th ST / Bl 55 (nb
CrossesI-55 (sb)
Location.25M S I-72
RouteInterstate 55
CountySangamon County
StateIllinois
Coordinates39.73887, -89.64368
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating69.3 US tons
Inventory rating41.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length282 ft (85.9 m)
Longest span114 ft (34.7 m)
Deck width37 ft (11.4 m)
Roadway width34 ft (10.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,500 (2023)
Projected traffic7,929 by 2046
Trucks5%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$998,000
NavigationNot applicable (no waterway)

Frequently asked questions

When was 6th ST / Bl 55 (nb over I-55 (sb) built?

It was built in 1963, making it 62 years old in 2025. It was reconstructed in 2009.

What condition is 6th ST / Bl 55 (nb over I-55 (sb) in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in May 2023.

How much traffic does 6th ST / Bl 55 (nb over I-55 (sb) carry?

About 10,500 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is 6th ST / Bl 55 (nb over I-55 (sb)?

The structure is 282 ft (85.9 m) long with a longest span of 114 ft (34.7 m) and a deck 37 ft wide.

Who owns 6th ST / Bl 55 (nb over I-55 (sb)?

It is owned by the State Highway Agency.