US Bridges

State Route 70 over Thermalito Canal

Fair

Butte County, California · 03-BUT-070-16.31 · Structure no. 12 0163

Built
1963
62 years old
Condition
Fair
inspected August 2023
Type
Tee Beam
Concrete Continuous
Length
187 ft
3 main spans
Daily traffic
19,000
2020 count
Owner
State
State Highway Agency

About this bridge

State Route 70 over Thermalito Canal is a concrete continuous tee beam carrying State Route 70 over Thermalito Canal in Butte County, California. It was built in 1963, so it is 62 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 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 19,000 vehicles a day, projected to reach 32,471 by 2041. The structure is 187 ft (57 m) long and 89 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesState Route 70
CrossesThermalito Canal
Location03-BUT-070-16.31
RouteState Highway 70
CountyButte County
StateCalifornia
Coordinates39.53101, -121.57902
Functional classUrban Other Principal 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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating37.8 US tons
Inventory rating29.3 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length187 ft (57 m)
Longest span74 ft (22.6 m)
Deck width89 ft (27 m)
Roadway width84 ft (25.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic19,000 (2020)
Projected traffic32,471 by 2041
Trucks0%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes

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 Thermalito Canal built?

It was built in 1963, making it 62 years old in 2025.

What condition is State Route 70 over Thermalito Canal 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 August 2023.

How much traffic does State Route 70 over Thermalito Canal carry?

About 19,000 vehicles per day (2020 count).

How long is State Route 70 over Thermalito Canal?

The structure is 187 ft (57 m) long with a longest span of 74 ft (22.6 m) and a deck 89 ft wide.

Who owns State Route 70 over Thermalito Canal?

It is owned by the State Highway Agency.