US Bridges

Old US 50 over Rock Spring Brook

Fair

St. Clair County, Illinois · East Ofallon · Structure no. 082026800000000

Built
1952
73 years old, rebuilt 1981
Condition
Fair
inspected September 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
60 ft
1 main span
Daily traffic
8,600
2023 count
Owner
State
State Highway Agency

About this bridge

Old US 50 over Rock Spring Brook is a prestressed concrete box beam or girders - multiple carrying Old US 50 over Rock Spring Brook in St. Clair County, Illinois. It was built in 1952 and reconstructed in 1981, so it is 73 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 8,600 vehicles a day, roughly 5% of them trucks, projected to reach 10,403 by 2046. The structure is 60 ft (18.3 m) long and 42 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesOld US 50
CrossesRock Spring Brook
LocationEast Ofallon
CountySt. Clair County
StateIllinois
Coordinates38.5809, -89.89079
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating62.5 US tons
Inventory rating38.9 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHS 20
Structure length60 ft (18.3 m)
Longest span56 ft (17.1 m)
Deck width42 ft (12.8 m)
Roadway width41 ft (12.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,600 (2023)
Projected traffic10,403 by 2046
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Old US 50 over Rock Spring Brook built?

It was built in 1952, making it 73 years old in 2025. It was reconstructed in 1981.

What condition is Old US 50 over Rock Spring Brook 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 September 2024.

How much traffic does Old US 50 over Rock Spring Brook carry?

About 8,600 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Old US 50 over Rock Spring Brook?

The structure is 60 ft (18.3 m) long with a longest span of 56 ft (17.1 m) and a deck 42 ft wide.

Who owns Old US 50 over Rock Spring Brook?

It is owned by the State Highway Agency.