US Bridges

SR 12 over Calabazas Creek

Fair

Sonoma County, California · 04-SON-012-29.41 · Structure no. 20 0026

Built
1989
36 years old
Condition
Fair
inspected September 2024
Type
Box Beam or Girders - Multiple
Concrete
Length
78 ft
1 main span
Daily traffic
15,300
2012 count
Owner
State
State Highway Agency

About this bridge

SR 12 over Calabazas Creek is a concrete box beam or girders - multiple carrying SR 12 over Calabazas Creek in Sonoma County, California. It was built in 1989, so it is 36 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 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 15,300 vehicles a day, projected to reach 23,747 by 2046. The structure is 78 ft (23.8 m) long and 58 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesSR 12
CrossesCalabazas Creek
Location04-SON-012-29.41
RouteState Highway 12
CountySonoma County
StateCalifornia
Coordinates38.38733, -122.52044
Functional classUrban Principal Arterial - Interstate

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure8 Very GoodNo problems noted.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length78 ft (23.8 m)
Longest span78 ft (23.8 m)
Deck width58 ft (17.7 m)
Roadway width54 ft (16.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15,300 (2012)
Projected traffic23,747 by 2046
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 12 over Calabazas Creek built?

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

What condition is SR 12 over Calabazas 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 SR 12 over Calabazas Creek carry?

About 15,300 vehicles per day (2012 count).

How long is SR 12 over Calabazas Creek?

The structure is 78 ft (23.8 m) long with a longest span of 78 ft (23.8 m) and a deck 58 ft wide.

Who owns SR 12 over Calabazas Creek?

It is owned by the State Highway Agency.