US Bridges

Il 29 over Black Branch

Fair

Sangamon County, Illinois · .37M SE Main-Rochstr · Structure no. 084004400000000

Built
1954
71 years old, rebuilt 2003
Condition
Fair
inspected November 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
33 ft
1 main span
Daily traffic
11,600
2023 count
Owner
State
State Highway Agency

About this bridge

Il 29 over Black Branch is a steel stringer/multi-beam or girder carrying Il 29 over Black Branch in Sangamon County, Illinois. It was built in 1954 and reconstructed in 2003, so it is 71 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 11,600 vehicles a day, roughly 10% of them trucks, projected to reach 5,151 by 2046. The structure is 33 ft (10.1 m) long and 57 ft wide. If it were closed, the detour would be 11.8 mi (19 km).

Location

Open in Google Maps
CarriesIl 29
CrossesBlack Branch
Location.37M SE Main-Rochstr
RouteState Highway 29
CountySangamon County
StateIllinois
Coordinates39.74653, -89.53161
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionNovember 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 adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating65 US tons
Inventory rating38.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length33 ft (10.1 m)
Longest span31 ft (9.5 m)
Deck width57 ft (17.3 m)
Roadway width41 ft (12.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,600 (2023)
Projected traffic5,151 by 2046
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.8 mi (19 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 Il 29 over Black Branch built?

It was built in 1954, making it 71 years old in 2025. It was reconstructed in 2003.

What condition is Il 29 over Black Branch 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 November 2024.

How much traffic does Il 29 over Black Branch carry?

About 11,600 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Il 29 over Black Branch?

The structure is 33 ft (10.1 m) long with a longest span of 31 ft (9.5 m) and a deck 57 ft wide.

Who owns Il 29 over Black Branch?

It is owned by the State Highway Agency.