US Bridges

Big Oak Flat Road over Wildcat Creek

Fair

Mariposa County, California · 7.0 Miles East from El Po · Structure no. 8800020P0000000

Built
1939
86 years old
Condition
Fair
inspected September 2024
Type
Arch - Deck
Concrete
Length
275 ft
1 main span
Daily traffic
2,530
2022 count
Owner
Federal
National Park Service

About this bridge

Big Oak Flat Road over Wildcat Creek is a concrete arch - deck carrying Big Oak Flat Road over Wildcat Creek in Mariposa County, California. It was built in 1939, so it is 86 years old, older than the California average of 54.8 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 2,530 vehicles a day, roughly 1% of them trucks, projected to reach 3,036 by 2042. The structure is 275 ft (83.9 m) long and 33 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesBig Oak Flat Road
CrossesWildcat Creek
Location7.0 Miles East from El Po
RouteFederal Lands Road 13
CountyMariposa County
StateCalifornia
Coordinates37.72505, -119.71814
Functional classRural Minor 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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44 US tons
Inventory rating26 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1 (+9 approach)
Design loadH 15
Structure length275 ft (83.9 m)
Longest span116 ft (35.4 m)
Deck width33 ft (10.1 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,530 (2022)
Projected traffic3,036 by 2042
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerNational Park Service
Maintained byNational Park Service
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost$137,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Big Oak Flat Road over Wildcat Creek built?

It was built in 1939, making it 86 years old in 2025.

What condition is Big Oak Flat Road over Wildcat 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 Big Oak Flat Road over Wildcat Creek carry?

About 2,530 vehicles per day (2022 count), of which roughly 1% are trucks.

How long is Big Oak Flat Road over Wildcat Creek?

The structure is 275 ft (83.9 m) long with a longest span of 116 ft (35.4 m) and a deck 33 ft wide.

Who owns Big Oak Flat Road over Wildcat Creek?

It is owned by the National Park Service.