US Bridges

Thornton Road over Beaver Slough

Fair

San Joaquin County, California · 0.75 MI S Kile RD · Structure no. 29C0133

Built
1941
84 years old
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
135 ft
7 main spans
Daily traffic
1,232
2013 count
Owner
County
County Highway Agency

About this bridge

Thornton Road over Beaver Slough is a wood or timber stringer/multi-beam or girder carrying Thornton Road over Beaver Slough in San Joaquin County, California. It was built in 1941, so it is 84 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 1,232 vehicles a day, roughly 2% of them trucks, projected to reach 2,475 by 2042. The structure is 135 ft (41.1 m) long and 25 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

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CarriesThornton Road
CrossesBeaver Slough
Location0.75 MI S Kile RD
RouteCounty Highway 0
CountySan Joaquin County
StateCalifornia
Coordinates38.20783, -121.40969
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
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 protection7 GoodSome minor problems.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
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 adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating37.1 US tons
Inventory rating23.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckConcrete, cast-in-place
Main spans7
Design loadUnknown
Structure length135 ft (41.1 m)
Longest span19 ft (5.8 m)
Deck width25 ft (7.7 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,232 (2013)
Projected traffic2,475 by 2042
Trucks2%
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 Thornton Road over Beaver Slough built?

It was built in 1941, making it 84 years old in 2025.

What condition is Thornton Road over Beaver Slough 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 January 2024.

How much traffic does Thornton Road over Beaver Slough carry?

About 1,232 vehicles per day (2013 count), of which roughly 2% are trucks.

How long is Thornton Road over Beaver Slough?

The structure is 135 ft (41.1 m) long with a longest span of 19 ft (5.8 m) and a deck 25 ft wide.

Who owns Thornton Road over Beaver Slough?

It is owned by the County Highway Agency.