US Bridges

CH-29 over Knob Creek

Fair

Jefferson County, Illinois · 2.5 MI Nnw Wville · Structure no. 041305800000000

Built
1909
116 years old
Condition
Fair
inspected August 2024
Type
Channel Beam
Concrete
Length
34 ft
1 main span
Daily traffic
100
2021 count
Owner
County
County Highway Agency

About this bridge

CH-29 over Knob Creek is a concrete channel beam carrying CH-29 over Knob Creek in Jefferson County, Illinois. It was built in 1909, so it is 116 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 100 vehicles a day, roughly 13% of them trucks, projected to reach 101 by 2046. The structure is 34 ft (10.5 m) long and 26 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesCH-29
CrossesKnob Creek
Location2.5 MI Nnw Wville
RouteCounty Highway 0
CountyJefferson County
StateIllinois
Coordinates38.25686, -89.0584
Functional classRural Local

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating53.6 US tons
Inventory rating32.2 US tons

Structure

Structure typeChannel Beam
MaterialConcrete
DeckConcrete, precast panels
Main spans1
Design loadUnknown
Structure length34 ft (10.5 m)
Longest span30 ft (9.1 m)
Deck width26 ft (8 m)
Roadway width25 ft (7.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic100 (2021)
Projected traffic101 by 2046
Trucks13%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$112,000
NavigationNo navigation control on waterway

Frequently asked questions

When was CH-29 over Knob Creek built?

It was built in 1909, making it 116 years old in 2025.

What condition is CH-29 over Knob Creek 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 August 2024.

How much traffic does CH-29 over Knob Creek carry?

About 100 vehicles per day (2021 count), of which roughly 13% are trucks.

How long is CH-29 over Knob Creek?

The structure is 34 ft (10.5 m) long with a longest span of 30 ft (9.1 m) and a deck 26 ft wide.

Who owns CH-29 over Knob Creek?

It is owned by the County Highway Agency.