US Bridges

State Route 70 over Flag Canyon Crk

Fair

Butte County, California · 03-BUT-070-24.26 · Structure no. 12 0204

Built
2015
10 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
94 ft
1 main span
Daily traffic
2,400
2020 count
Owner
State
State Highway Agency

About this bridge

State Route 70 over Flag Canyon Crk is a prestressed concrete stringer/multi-beam or girder carrying State Route 70 over Flag Canyon Crk in Butte County, California. It was built in 2015, so it is 10 years old, younger 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 5 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 2,400 vehicles a day, roughly 11% of them trucks, projected to reach 3,747 by 2041. The structure is 94 ft (28.7 m) long and 43 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesState Route 70
CrossesFlag Canyon Crk
Location03-BUT-070-24.26
RouteState Highway 70
CountyButte County
StateCalifornia
Coordinates39.62825, -121.58973
Functional classRural Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating46.4 US tons
Inventory rating35.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadGreater than HL 93
Structure length94 ft (28.7 m)
Longest span92 ft (28 m)
Deck width43 ft (13 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,400 (2020)
Projected traffic3,747 by 2041
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 State Route 70 over Flag Canyon Crk built?

It was built in 2015, making it 10 years old in 2025.

What condition is State Route 70 over Flag Canyon Crk 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 2023.

How much traffic does State Route 70 over Flag Canyon Crk carry?

About 2,400 vehicles per day (2020 count), of which roughly 11% are trucks.

How long is State Route 70 over Flag Canyon Crk?

The structure is 94 ft (28.7 m) long with a longest span of 92 ft (28 m) and a deck 43 ft wide.

Who owns State Route 70 over Flag Canyon Crk?

It is owned by the State Highway Agency.