US Bridges

Madrone Ave over San Anselmo Creek

Fair

Marin County, California · 150 Ft E of Nokomis · Structure no. 27C0080

Built
1930
95 years old
Condition
Fair
inspected September 2024
Type
Girder and Floorbeam System
Concrete
Length
28 ft
1 main span
Daily traffic
1,500
2011 count
Owner
City
City or Municipal Highway Agency

About this bridge

Madrone Ave over San Anselmo Creek is a concrete girder and floorbeam system carrying Madrone Ave over San Anselmo Creek in Marin County, California. It was built in 1930, so it is 95 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 1,500 vehicles a day, roughly 2% of them trucks, projected to reach 1,330 by 2046. The structure is 28 ft (8.5 m) long and 30 ft wide. If it were closed, the detour would be 44.1 mi (71 km).

Location

Open in Google Maps
CarriesMadrone Ave
CrossesSan Anselmo Creek
Location150 Ft E of Nokomis
RouteCity Street 0
CountyMarin County
StateCalifornia
Coordinates37.97813, -122.56606
Functional classUrban 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
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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating30.3 US tons
Inventory rating18.2 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length28 ft (8.5 m)
Longest span26 ft (7.9 m)
Deck width30 ft (9.2 m)
Roadway width18 ft (5.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,500 (2011)
Projected traffic1,330 by 2046
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed44.1 mi (71 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 Madrone Ave over San Anselmo Creek built?

It was built in 1930, making it 95 years old in 2025.

What condition is Madrone Ave over San Anselmo 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 Madrone Ave over San Anselmo Creek carry?

About 1,500 vehicles per day (2011 count), of which roughly 2% are trucks.

How long is Madrone Ave over San Anselmo Creek?

The structure is 28 ft (8.5 m) long with a longest span of 26 ft (7.9 m) and a deck 30 ft wide.

Who owns Madrone Ave over San Anselmo Creek?

It is owned by the City or Municipal Highway Agency.