US Bridges

Jackson Hwy. over Newaukum Overflow

Fair

Lewis County, Washington · 2.45 N JCT SR 508 · Structure no. 083260000000000

Built
1926
99 years old, rebuilt 1978
Condition
Fair
inspected February 2023
Type
Tee Beam
Concrete Continuous
Length
55 ft
2 main spans
Daily traffic
3,427
2019 count
Owner
County
County Highway Agency

About this bridge

Jackson Hwy. over Newaukum Overflow is a concrete continuous tee beam carrying Jackson Hwy. over Newaukum Overflow in Lewis County, Washington. It was built in 1926 and reconstructed in 1978, so it is 99 years old, older 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 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 3,427 vehicles a day, roughly 13% of them trucks, projected to reach 6,376 by 2040. The structure is 55 ft (16.8 m) long and 39 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

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CarriesJackson Hwy.
CrossesNewaukum Overflow
Location2.45 N JCT SR 508
RouteCounty Highway 94000
CountyLewis County
StateWashington
Coordinates46.60532, -122.86823
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
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionFebruary 2023
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 adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating73 US tons
Inventory rating44 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length55 ft (16.8 m)
Longest span27 ft (8.2 m)
Deck width39 ft (11.9 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,427 (2019)
Projected traffic6,376 by 2040
Trucks13%
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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost$993,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Jackson Hwy. over Newaukum Overflow built?

It was built in 1926, making it 99 years old in 2025. It was reconstructed in 1978.

What condition is Jackson Hwy. over Newaukum Overflow 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 February 2023.

How much traffic does Jackson Hwy. over Newaukum Overflow carry?

About 3,427 vehicles per day (2019 count), of which roughly 13% are trucks.

How long is Jackson Hwy. over Newaukum Overflow?

The structure is 55 ft (16.8 m) long with a longest span of 27 ft (8.2 m) and a deck 39 ft wide.

Who owns Jackson Hwy. over Newaukum Overflow?

It is owned by the County Highway Agency.