US Bridges

Harney Drive over Sonoma Creek

Fair

Sonoma County, California · Sonoma State Institution · Structure no. 20I0001

Built
1935
90 years old
Condition
Fair
inspected May 2023
Type
Tee Beam
Concrete Continuous
Length
159 ft
3 main spans
Daily traffic
250
2015 count
Owner
State
Other State Agency

About this bridge

Harney Drive over Sonoma Creek is a concrete continuous tee beam carrying Harney Drive over Sonoma Creek in Sonoma County, California. It was built in 1935, so it is 90 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 250 vehicles a day, roughly 3% of them trucks, projected to reach 382 by 2040. The structure is 159 ft (48.5 m) long and 32 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

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CarriesHarney Drive
CrossesSonoma Creek
LocationSonoma State Institution
RouteState Lands Road 0
CountySonoma County
StateCalifornia
Coordinates38.34957, -122.51524
Functional classUrban Local

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating35.1 US tons
Inventory rating26.8 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 15
Structure length159 ft (48.5 m)
Longest span52 ft (15.8 m)
Deck width32 ft (9.8 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic250 (2015)
Projected traffic382 by 2040
Trucks3%
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

OwnerOther State Agency
Maintained byOther State 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 Harney Drive over Sonoma Creek built?

It was built in 1935, making it 90 years old in 2025.

What condition is Harney Drive 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 Harney Drive over Sonoma Creek carry?

About 250 vehicles per day (2015 count), of which roughly 3% are trucks.

How long is Harney Drive over Sonoma Creek?

The structure is 159 ft (48.5 m) long with a longest span of 52 ft (15.8 m) and a deck 32 ft wide.

Who owns Harney Drive over Sonoma Creek?

It is owned by the Other State Agency.