US Bridges

3100 RD Mile 8 over Onion Creek

Fair

Montgomery County, Kansas · 1.0W of Jefferson · Structure no. 000000000630378

Built
1930
95 years old, rebuilt 1970
Condition
Fair
inspected March 2023
Type
Slab
Concrete
Length
30 ft
1 main span
Daily traffic
111
2010 count
Owner
County
County Highway Agency

About this bridge

3100 RD Mile 8 over Onion Creek is a concrete slab carrying 3100 RD Mile 8 over Onion Creek in Montgomery County, Kansas. It was built in 1930 and reconstructed in 1970, so it is 95 years old, older than the Kansas average of 52.8 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 111 vehicles a day, projected to reach 133 by 2039. The structure is 30 ft (9.1 m) long and 29 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
Carries3100 RD Mile 8
CrossesOnion Creek
Location1.0W of Jefferson
RouteCounty Highway 476
CountyMontgomery County
StateKansas
Coordinates37.10965, -95.78101
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment7: Better than present minimum criteria
Operating rating32.7 US tons
Inventory rating23.8 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length30 ft (9.1 m)
Longest span28 ft (8.5 m)
Deck width29 ft (8.9 m)
Roadway width28 ft (8.6 m)
Vertical clearance over deck100 ft (30.5 m)

Traffic and service

Average daily traffic111 (2010)
Projected traffic133 by 2039
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 3100 RD Mile 8 over Onion Creek built?

It was built in 1930, making it 95 years old in 2025. It was reconstructed in 1970.

What condition is 3100 RD Mile 8 over Onion 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 March 2023.

How much traffic does 3100 RD Mile 8 over Onion Creek carry?

About 111 vehicles per day (2010 count).

How long is 3100 RD Mile 8 over Onion Creek?

The structure is 30 ft (9.1 m) long with a longest span of 28 ft (8.5 m) and a deck 29 ft wide.

Who owns 3100 RD Mile 8 over Onion Creek?

It is owned by the County Highway Agency.