US Bridges

4th ST East over Nathanson Creek

Fair

Sonoma County, California · 0.1 MI N of E Napa ST · Structure no. 20C0495

Built
1914
111 years old
Condition
Fair
inspected June 2023
Type
Arch - Deck
Concrete
Length
35 ft
1 main span
Daily traffic
2,100
2015 count
Owner
City
City or Municipal Highway Agency

About this bridge

4th ST East over Nathanson Creek is a concrete arch - deck carrying 4th ST East over Nathanson Creek in Sonoma County, California. It was built in 1914, so it is 111 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 2,100 vehicles a day, roughly 1% of them trucks, projected to reach 2,717 by 2045. The structure is 35 ft (10.7 m) long and 33 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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Carries4th ST East
CrossesNathanson Creek
Location0.1 MI N of E Napa ST
RouteCity Street 0
CountySonoma County
StateCalifornia
Coordinates38.29251, -122.44965
Functional classUrban 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
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating28.2 US tons
Inventory rating16.8 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckNot applicable
Main spans1
Design loadUnknown
Structure length35 ft (10.7 m)
Longest span30 ft (9.1 m)
Deck width33 ft (10.1 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,100 (2015)
Projected traffic2,717 by 2045
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 4th ST East over Nathanson Creek built?

It was built in 1914, making it 111 years old in 2025.

What condition is 4th ST East over Nathanson 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 June 2023.

How much traffic does 4th ST East over Nathanson Creek carry?

About 2,100 vehicles per day (2015 count), of which roughly 1% are trucks.

How long is 4th ST East over Nathanson Creek?

The structure is 35 ft (10.7 m) long with a longest span of 30 ft (9.1 m) and a deck 33 ft wide.

Who owns 4th ST East over Nathanson Creek?

It is owned by the City or Municipal Highway Agency.