US Bridges

W Bigs-Gridly RD over Hamilton Slough

Poor

Butte County, California · 0.4 MI S of B ST · Structure no. 12C0058

Built
1950
75 years old
Condition
Poor
inspected October 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
24 ft
1 main span
Daily traffic
800
2019 count
Owner
City
City or Municipal Highway Agency

About this bridge

W Bigs-Gridly RD over Hamilton Slough is a steel stringer/multi-beam or girder carrying W Bigs-Gridly RD over Hamilton Slough in Butte County, California. It was built in 1950, so it is 75 years old, older than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 800 vehicles a day, roughly 3% of them trucks, projected to reach 1,670 by 2041. The structure is 24 ft (7.3 m) long and 33 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

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CarriesW Bigs-Gridly RD
CrossesHamilton Slough
Location0.4 MI S of B ST
RouteCity Street 0
CountyButte County
StateCalifornia
Coordinates39.40684, -121.71618
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 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 geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating87.5 US tons
Inventory rating52.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length24 ft (7.3 m)
Longest span23 ft (7 m)
Deck width33 ft (10 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic800 (2019)
Projected traffic1,670 by 2041
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$117,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was W Bigs-Gridly RD over Hamilton Slough built?

It was built in 1950, making it 75 years old in 2025.

What condition is W Bigs-Gridly RD over Hamilton Slough in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in October 2024.

How much traffic does W Bigs-Gridly RD over Hamilton Slough carry?

About 800 vehicles per day (2019 count), of which roughly 3% are trucks.

How long is W Bigs-Gridly RD over Hamilton Slough?

The structure is 24 ft (7.3 m) long with a longest span of 23 ft (7 m) and a deck 33 ft wide.

Who owns W Bigs-Gridly RD over Hamilton Slough?

It is owned by the City or Municipal Highway Agency.