US Bridges

Il 138 over Big Branch

Good

Macoupin County, Illinois · .3M W Il 4(MT Clare) · Structure no. 059005100000000

Built
1991
34 years old
Condition
Good
inspected February 2022
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
70 ft
1 main span
Daily traffic
1,100
2023 count
Owner
State
State Highway Agency

About this bridge

Il 138 over Big Branch is a prestressed concrete stringer/multi-beam or girder carrying Il 138 over Big Branch in Macoupin County, Illinois. It was built in 1991, so it is 34 years old, younger than the Illinois average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 1,100 vehicles a day, roughly 7% of them trucks, projected to reach 1,212 by 2046. The structure is 70 ft (21.3 m) long and 41 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesIl 138
CrossesBig Branch
Location.3M W Il 4(MT Clare)
RouteState Highway 138
CountyMacoupin County
StateIllinois
Coordinates39.09943, -89.82129
Functional classUrban Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionFebruary 2022
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation8: Equal to present desirable criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating85.3 US tons
Inventory rating41.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length70 ft (21.3 m)
Longest span68 ft (20.6 m)
Deck width41 ft (12.4 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,100 (2023)
Projected traffic1,212 by 2046
Trucks7%
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 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 Il 138 over Big Branch built?

It was built in 1991, making it 34 years old in 2025.

What condition is Il 138 over Big Branch in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in February 2022.

How much traffic does Il 138 over Big Branch carry?

About 1,100 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is Il 138 over Big Branch?

The structure is 70 ft (21.3 m) long with a longest span of 68 ft (20.6 m) and a deck 41 ft wide.

Who owns Il 138 over Big Branch?

It is owned by the State Highway Agency.