US Bridges

Ill 15 over Harding Ditch

Fair

St. Clair County, Illinois · 0.3 M W JCT 157 · Structure no. 082003900000000

Built
1940
85 years old, rebuilt 1984
Condition
Fair
inspected March 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
157 ft
3 main spans
Daily traffic
30,000
2023 count
Owner
State
State Highway Agency

About this bridge

Ill 15 over Harding Ditch is a steel continuous stringer/multi-beam or girder carrying Ill 15 over Harding Ditch in St. Clair County, Illinois. It was built in 1940 and reconstructed in 1984, so it is 85 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 30,000 vehicles a day, roughly 6% of them trucks, projected to reach 14,696 by 2046. The structure is 157 ft (47.9 m) long and 71 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesIll 15
CrossesHarding Ditch
Location0.3 M W JCT 157
RouteState Highway 15
CountySt. Clair County
StateIllinois
Coordinates38.57014, -90.09423
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
Deck8 Very GoodNo problems noted.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating60.4 US tons
Inventory rating36 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length157 ft (47.9 m)
Longest span60 ft (18.3 m)
Deck width71 ft (21.7 m)
Roadway width65 ft (19.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30,000 (2023)
Projected traffic14,696 by 2046
Trucks6%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Ill 15 over Harding Ditch built?

It was built in 1940, making it 85 years old in 2025. It was reconstructed in 1984.

What condition is Ill 15 over Harding Ditch 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 March 2024.

How much traffic does Ill 15 over Harding Ditch carry?

About 30,000 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is Ill 15 over Harding Ditch?

The structure is 157 ft (47.9 m) long with a longest span of 60 ft (18.3 m) and a deck 71 ft wide.

Who owns Ill 15 over Harding Ditch?

It is owned by the State Highway Agency.