US Bridges

S Main ST over FAI 255

Fair

St. Clair County, Illinois · 0.1MI SE Dupo · Structure no. 082021600000000

Built
1983
42 years old
Condition
Fair
inspected January 2025
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
252 ft
2 main spans
Daily traffic
6,200
2023 count
Owner
State
State Highway Agency

About this bridge

S Main ST over FAI 255 is a steel continuous stringer/multi-beam or girder carrying S Main ST over FAI 255 in St. Clair County, Illinois. It was built in 1983, so it is 42 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 6,200 vehicles a day, roughly 10% of them trucks, projected to reach 7,222 by 2046. The structure is 252 ft (76.9 m) long and 69 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesS Main ST
CrossesFAI 255
Location0.1MI SE Dupo
CountySt. Clair County
StateIllinois
Coordinates38.50878, -90.20513
Functional classUrban Minor 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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating70.3 US tons
Inventory rating41.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length252 ft (76.9 m)
Longest span135 ft (41.1 m)
Deck width69 ft (21.1 m)
Roadway width66 ft (20.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,200 (2023)
Projected traffic7,222 by 2046
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed6.2 mi (10 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 proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was S Main ST over FAI 255 built?

It was built in 1983, making it 42 years old in 2025.

What condition is S Main ST over FAI 255 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 January 2025.

How much traffic does S Main ST over FAI 255 carry?

About 6,200 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is S Main ST over FAI 255?

The structure is 252 ft (76.9 m) long with a longest span of 135 ft (41.1 m) and a deck 69 ft wide.

Who owns S Main ST over FAI 255?

It is owned by the State Highway Agency.