US Bridges

Aurora ST over Irwin CR

Fair

Mercer County, Missouri · S 2 T 66 N R 23 W · Structure no. 15331

Built
1999
26 years old
Condition
Fair
inspected December 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
50 ft
1 main span
Daily traffic
20
2024 count
Owner
County
County Highway Agency

About this bridge

Aurora ST over Irwin CR is a steel stringer/multi-beam or girder carrying Aurora ST over Irwin CR in Mercer County, Missouri. It was built in 1999, so it is 26 years old, younger than the Missouri average of 45.1 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 20 vehicles a day, roughly 20% of them trucks, projected to reach 22 by 2044. The structure is 50 ft (15.2 m) long and 20 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesAurora ST
CrossesIrwin CR
LocationS 2 T 66 N R 23 W
RouteCounty Highway 91
CountyMercer County
StateMissouri
Coordinates40.54575, -93.46285
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating30.8 US tons
Inventory rating18.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadOther
Structure length50 ft (15.2 m)
Longest span49 ft (14.9 m)
Deck width20 ft (6.2 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20 (2024)
Projected traffic22 by 2044
Trucks20%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed0.6 mi (1 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 Aurora ST over Irwin CR built?

It was built in 1999, making it 26 years old in 2025.

What condition is Aurora ST over Irwin CR 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 December 2023.

How much traffic does Aurora ST over Irwin CR carry?

About 20 vehicles per day (2024 count), of which roughly 20% are trucks.

How long is Aurora ST over Irwin CR?

The structure is 50 ft (15.2 m) long with a longest span of 49 ft (14.9 m) and a deck 20 ft wide.

Who owns Aurora ST over Irwin CR?

It is owned by the County Highway Agency.