US Bridges

FAS 1274 over Somonauk Creek

Fair

DeKalb County, Illinois · N 48th E 2725 · Structure no. 050305700000000

Built
1966
59 years old, rebuilt 2008
Condition
Fair
inspected June 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
129 ft
4 main spans
Daily traffic
3,100
2020 count
Owner
City
City or Municipal Highway Agency

About this bridge

FAS 1274 over Somonauk Creek is a steel continuous stringer/multi-beam or girder carrying FAS 1274 over Somonauk Creek in DeKalb County, Illinois. It was built in 1966 and reconstructed in 2008, so it is 59 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 3,100 vehicles a day, roughly 6% of them trucks, projected to reach 3,131 by 2046. The structure is 129 ft (39.2 m) long and 35 ft wide. If it were closed, the detour would be 18 mi (29 km).

Location

Open in Google Maps
CarriesFAS 1274
CrossesSomonauk Creek
LocationN 48th E 2725
RouteCounty Highway 0
CountyDeKalb County
StateIllinois
Coordinates41.63104, -88.65407
Functional classUrban 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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating72.9 US tons
Inventory rating43.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length129 ft (39.2 m)
Longest span32 ft (9.8 m)
Deck width35 ft (10.7 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,100 (2020)
Projected traffic3,131 by 2046
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed18 mi (29 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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$614,000
NavigationNo navigation control on waterway

Frequently asked questions

When was FAS 1274 over Somonauk Creek built?

It was built in 1966, making it 59 years old in 2025. It was reconstructed in 2008.

What condition is FAS 1274 over Somonauk 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 June 2024.

How much traffic does FAS 1274 over Somonauk Creek carry?

About 3,100 vehicles per day (2020 count), of which roughly 6% are trucks.

How long is FAS 1274 over Somonauk Creek?

The structure is 129 ft (39.2 m) long with a longest span of 32 ft (9.8 m) and a deck 35 ft wide.

Who owns FAS 1274 over Somonauk Creek?

It is owned by the City or Municipal Highway Agency.