US Bridges

N3920 over Flat Rock Creek

FairPosted for load

Okmulgee County, Oklahoma · 2.5 W; 0.5 S Preston · Structure no. 251160000000000

Built
1997
28 years old
Condition
Fair
inspected September 2024
Type
Tee Beam
Prestressed Concrete
Length
110 ft
3 main spans
Daily traffic
100
2022 count
Owner
County
County Highway Agency

About this bridge

N3920 over Flat Rock Creek is a prestressed concrete tee beam carrying N3920 over Flat Rock Creek in Okmulgee County, Oklahoma. It was built in 1997, so it is 28 years old, younger than the Oklahoma average of 47.8 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. Its operating status is: posted for load restriction.

It carries about 100 vehicles a day, roughly 10% of them trucks, projected to reach 160 by 2042. The structure is 110 ft (33.5 m) long and 28 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesN3920
CrossesFlat Rock Creek
Location2.5 W; 0.5 S Preston
RouteCounty Highway N3920
CountyOkmulgee County
StateOklahoma
Coordinates35.70249, -96.0336
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.
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 inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating46 US tons
Inventory rating27.4 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans3
Design loadHL 93
Structure length110 ft (33.5 m)
Longest span40 ft (12.2 m)
Deck width28 ft (8.5 m)
Roadway width26 ft (8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic100 (2022)
Projected traffic160 by 2042
Trucks10%
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 statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$534,000
NavigationNo navigation control on waterway

Frequently asked questions

When was N3920 over Flat Rock Creek built?

It was built in 1997, making it 28 years old in 2025.

What condition is N3920 over Flat Rock 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 September 2024.

How much traffic does N3920 over Flat Rock Creek carry?

About 100 vehicles per day (2022 count), of which roughly 10% are trucks.

How long is N3920 over Flat Rock Creek?

The structure is 110 ft (33.5 m) long with a longest span of 40 ft (12.2 m) and a deck 28 ft wide.

Who owns N3920 over Flat Rock Creek?

It is owned by the County Highway Agency.