US Bridges

Somonauk Road over Br Little Rock Creek

Fair

DeKalb County, Illinois · 625N 1550E · Structure no. 019303800000000

Built
1976
49 years old
Condition
Fair
inspected January 2023
Type
Culvert
Steel
Length
25 ft
2 main spans
Daily traffic
3,000
2021 count
Owner
County
County Highway Agency

About this bridge

Somonauk Road over Br Little Rock Creek is a steel culvert carrying Somonauk Road over Br Little Rock Creek in DeKalb County, Illinois. It was built in 1976, so it is 49 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 3,000 vehicles a day, roughly 10% of them trucks, projected to reach 3,360 by 2046. The structure is 25 ft (7.6 m) long. If it were closed, the detour would be 11.8 mi (19 km).

Location

Open in Google Maps
CarriesSomonauk Road
CrossesBr Little Rock Creek
Location625N 1550E
RouteCounty Highway 0
CountyDeKalb County
StateIllinois
Coordinates41.72265, -88.65051
Functional classRural Major Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48.9 US tons
Inventory rating35.7 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans2
Design loadHS 20
Structure length25 ft (7.6 m)
Longest span11 ft (3.5 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,000 (2021)
Projected traffic3,360 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 SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 Somonauk Road over Br Little Rock Creek built?

It was built in 1976, making it 49 years old in 2025.

What condition is Somonauk Road over Br Little Rock 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 January 2023.

How much traffic does Somonauk Road over Br Little Rock Creek carry?

About 3,000 vehicles per day (2021 count), of which roughly 10% are trucks.

How long is Somonauk Road over Br Little Rock Creek?

The structure is 25 ft (7.6 m) long with a longest span of 11 ft (3.5 m).

Who owns Somonauk Road over Br Little Rock Creek?

It is owned by the County Highway Agency.