US Bridges

TR 35A over Somonauk Creek

Good

LaSalle County, Illinois · N 46th E 2597 · Structure no. 050358000000000

Built
2005
20 years old
Condition
Good
inspected July 2022
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
137 ft
2 main spans
Daily traffic
950
2020 count
Owner
Town / Township
Town or Township Highway Agency

About this bridge

TR 35A over Somonauk Creek is a steel continuous stringer/multi-beam or girder carrying TR 35A over Somonauk Creek in LaSalle County, Illinois. It was built in 2005, so it is 20 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 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 950 vehicles a day, roughly 3% of them trucks, projected to reach 960 by 2046. The structure is 137 ft (41.9 m) long and 31 ft wide.

Location

Open in Google Maps
CarriesTR 35A
CrossesSomonauk Creek
LocationN 46th E 2597
RouteCounty Highway 0
CountyLaSalle County
StateIllinois
Coordinates41.60189, -88.68029
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.
Superstructure7 GoodSome minor problems.
Substructure8 Very GoodNo problems noted.
Channel and channel protection9 ExcellentNo problems noted.
Last inspectionJuly 2022
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than 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 rating48.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length137 ft (41.9 m)
Longest span64 ft (19.5 m)
Deck width31 ft (9.5 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic950 (2020)
Projected traffic960 by 2046
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerTown or Township Highway Agency
Maintained byTown or Township 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 TR 35A over Somonauk Creek built?

It was built in 2005, making it 20 years old in 2025.

What condition is TR 35A over Somonauk Creek 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 July 2022.

How much traffic does TR 35A over Somonauk Creek carry?

About 950 vehicles per day (2020 count), of which roughly 3% are trucks.

How long is TR 35A over Somonauk Creek?

The structure is 137 ft (41.9 m) long with a longest span of 64 ft (19.5 m) and a deck 31 ft wide.

Who owns TR 35A over Somonauk Creek?

It is owned by the Town or Township Highway Agency.