US Bridges

Thornton Road over Beaver Slough

Fair

San Joaquin County, California · 1 MI N Peltier Road · Structure no. 29C0012

Built
1958
67 years old
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
40 ft
2 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 1958, so it is 67 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 2,187 by 2042. The structure is 40 ft (12.2 m) long and 34 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

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CarriesThornton Road
CrossesBeaver Slough
Location1 MI N Peltier Road
RouteCounty Highway 0
CountySan Joaquin County
StateCalifornia
Coordinates38.20393, -121.40937
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating30 US tons
Inventory rating20 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckCorrugated steel
Main spans2
Design loadUnknown
Structure length40 ft (12.2 m)
Longest span18 ft (5.5 m)
Deck width34 ft (10.4 m)
Roadway width33 ft (10.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,232 (2013)
Projected traffic2,187 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 1958, making it 67 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 40 ft (12.2 m) long with a longest span of 18 ft (5.5 m) and a deck 34 ft wide.

Who owns Thornton Road over Beaver Slough?

It is owned by the County Highway Agency.