US Bridges

110th Ave SW over Black River

Fair

Thurston County, Washington · 0.75 W Littlerock RD · Structure no. 083430000000000

Built
1986
39 years old
Condition
Fair
inspected July 2024
Type
Slab
Prestressed Concrete
Length
180 ft
3 main spans
Daily traffic
2,339
2020 count
Owner
County
County Highway Agency

About this bridge

110th Ave SW over Black River is a prestressed concrete slab carrying 110th Ave SW over Black River in Thurston County, Washington. It was built in 1986, so it is 39 years old, younger than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 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 2,339 vehicles a day, roughly 15% of them trucks, projected to reach 3,762 by 2042. The structure is 180 ft (54.9 m) long and 32 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

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Carries110th Ave SW
CrossesBlack River
Location0.75 W Littlerock RD
RouteCounty Highway 15800
CountyThurston County
StateWashington
Coordinates46.92831, -123.00837
Functional classRural Major 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating97 US tons
Inventory rating58 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans3
Design loadHS 20
Structure length180 ft (54.9 m)
Longest span60 ft (18.3 m)
Deck width32 ft (9.8 m)
Roadway width29 ft (8.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,339 (2020)
Projected traffic3,762 by 2042
Trucks15%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$6.9 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was 110th Ave SW over Black River built?

It was built in 1986, making it 39 years old in 2025.

What condition is 110th Ave SW over Black River 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 July 2024.

How much traffic does 110th Ave SW over Black River carry?

About 2,339 vehicles per day (2020 count), of which roughly 15% are trucks.

How long is 110th Ave SW over Black River?

The structure is 180 ft (54.9 m) long with a longest span of 60 ft (18.3 m) and a deck 32 ft wide.

Who owns 110th Ave SW over Black River?

It is owned by the County Highway Agency.