US Bridges

N3120 over West Rock Creek

Fair

Garvin County, Oklahoma · 2.5 W .8 N Elmore City · Structure no. 223140000000000

Built
1989
36 years old
Condition
Fair
inspected April 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
102 ft
1 main span
Daily traffic
100
2022 count
Owner
County
County Highway Agency

About this bridge

N3120 over West Rock Creek is a prestressed concrete stringer/multi-beam or girder carrying N3120 over West Rock Creek in Garvin County, Oklahoma. It was built in 1989, so it is 36 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.

It carries about 100 vehicles a day, roughly 10% of them trucks, projected to reach 160 by 2042. The structure is 102 ft (31.2 m) long and 29 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesN3120
CrossesWest Rock Creek
Location2.5 W .8 N Elmore City
RouteCounty Highway N3120
CountyGarvin County
StateOklahoma
Coordinates34.63503, -97.44033
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.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating47.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length102 ft (31.2 m)
Longest span100 ft (30.5 m)
Deck width29 ft (8.7 m)
Roadway width27 ft (8.2 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 closed1.9 mi (3 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$508,000
NavigationNo navigation control on waterway

Frequently asked questions

When was N3120 over West Rock Creek built?

It was built in 1989, making it 36 years old in 2025.

What condition is N3120 over West 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 April 2024.

How much traffic does N3120 over West Rock Creek carry?

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

How long is N3120 over West Rock Creek?

The structure is 102 ft (31.2 m) long with a longest span of 100 ft (30.5 m) and a deck 29 ft wide.

Who owns N3120 over West Rock Creek?

It is owned by the County Highway Agency.