US Bridges

I-55 (sb) over Lake Springfield

Fair

Sangamon County, Illinois · 3M S I-72 · Structure no. 084049900000000

Built
2001
24 years old
Condition
Fair
inspected June 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
722 ft
5 main spans
Daily traffic
21,900
2023 count
Owner
State
State Highway Agency

About this bridge

I-55 (sb) over Lake Springfield is a steel continuous stringer/multi-beam or girder carrying I-55 (sb) over Lake Springfield in Sangamon County, Illinois. It was built in 2001, so it is 24 years old, younger 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 21,900 vehicles a day, roughly 22% of them trucks, projected to reach 22,018 by 2046. The structure is 722 ft (220.2 m) long and 62 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-55 (sb)
CrossesLake Springfield
Location3M S I-72
RouteInterstate 55
CountySangamon County
StateIllinois
Coordinates39.69654, -89.64243
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating97.6 US tons
Inventory rating58.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20 + Mod
Structure length722 ft (220.2 m)
Longest span158 ft (48.2 m)
Deck width62 ft (18.9 m)
Roadway width59 ft (18 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic21,900 (2023)
Projected traffic22,018 by 2046
Trucks22%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was I-55 (sb) over Lake Springfield built?

It was built in 2001, making it 24 years old in 2025.

What condition is I-55 (sb) over Lake Springfield 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 June 2024.

How much traffic does I-55 (sb) over Lake Springfield carry?

About 21,900 vehicles per day (2023 count), of which roughly 22% are trucks.

How long is I-55 (sb) over Lake Springfield?

The structure is 722 ft (220.2 m) long with a longest span of 158 ft (48.2 m) and a deck 62 ft wide.

Who owns I-55 (sb) over Lake Springfield?

It is owned by the State Highway Agency.