US Bridges

Warm Springs RD over Sonoma Creek

Fair

Sonoma County, California · 2.8 MI S of SR 12 · Structure no. 20C0218

Built
1931
94 years old
Condition
Fair
inspected May 2023
Type
Tee Beam
Concrete
Length
42 ft
1 main span
Daily traffic
800
2015 count
Owner
County
County Highway Agency

About this bridge

Warm Springs RD over Sonoma Creek is a concrete tee beam carrying Warm Springs RD over Sonoma Creek in Sonoma County, California. It was built in 1931, so it is 94 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 800 vehicles a day, roughly 5% of them trucks, projected to reach 1,830 by 2040. The structure is 42 ft (12.8 m) long and 25 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesWarm Springs RD
CrossesSonoma Creek
Location2.8 MI S of SR 12
RouteCounty Highway 0
CountySonoma County
StateCalifornia
Coordinates38.38079, -122.5522
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
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 inspectionMay 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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating28.5 US tons
Inventory rating22.2 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length42 ft (12.8 m)
Longest span39 ft (11.9 m)
Deck width25 ft (7.7 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic800 (2015)
Projected traffic1,830 by 2040
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Warm Springs RD over Sonoma Creek built?

It was built in 1931, making it 94 years old in 2025.

What condition is Warm Springs RD over Sonoma 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 May 2023.

How much traffic does Warm Springs RD over Sonoma Creek carry?

About 800 vehicles per day (2015 count), of which roughly 5% are trucks.

How long is Warm Springs RD over Sonoma Creek?

The structure is 42 ft (12.8 m) long with a longest span of 39 ft (11.9 m) and a deck 25 ft wide.

Who owns Warm Springs RD over Sonoma Creek?

It is owned by the County Highway Agency.