US Bridges

TR 105 over I-39/US 51

Fair

LaSalle County, Illinois · 1 MI S of US 34 · Structure no. 050016600000000

Built
1977
48 years old
Condition
Fair
inspected September 2024
Type
Box Beam or Girders - Single or Spread
Steel Continuous
Length
257 ft
2 main spans
Daily traffic
225
2020 count
Owner
State
State Highway Agency

About this bridge

TR 105 over I-39/US 51 is a steel continuous box beam or girders - single or spread carrying TR 105 over I-39/US 51 in LaSalle County, Illinois. It was built in 1977, so it is 48 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 5 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 225 vehicles a day, roughly 5% of them trucks, projected to reach 227 by 2046. The structure is 257 ft (78.3 m) long and 30 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesTR 105
CrossesI-39/US 51
Location1 MI S of US 34
RouteCounty Highway 0
CountyLaSalle County
StateIllinois
Coordinates41.53926, -89.05957
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating76.4 US tons
Inventory rating45.7 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2 (+2 approach)
Design loadHS 20
Structure length257 ft (78.3 m)
Longest span105 ft (32 m)
Deck width30 ft (9.1 m)
Roadway width27 ft (8.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic225 (2020)
Projected traffic227 by 2046
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was TR 105 over I-39/US 51 built?

It was built in 1977, making it 48 years old in 2025.

What condition is TR 105 over I-39/US 51 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 September 2024.

How much traffic does TR 105 over I-39/US 51 carry?

About 225 vehicles per day (2020 count), of which roughly 5% are trucks.

How long is TR 105 over I-39/US 51?

The structure is 257 ft (78.3 m) long with a longest span of 105 ft (32 m) and a deck 30 ft wide.

Who owns TR 105 over I-39/US 51?

It is owned by the State Highway Agency.