US Bridges

SR 507 over Nisqually River

Fair

Thurston County, Washington · 2.4 N JCT SR 510 · Structure no. 0013055A0000000

Built
1987
38 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
284 ft
3 main spans
Daily traffic
22,357
2023 count
Owner
State
State Highway Agency

About this bridge

SR 507 over Nisqually River is a prestressed concrete continuous stringer/multi-beam or girder carrying SR 507 over Nisqually River in Thurston County, Washington. It was built in 1987, so it is 38 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 22,357 vehicles a day, roughly 5% of them trucks, projected to reach 32,844 by 2039. The structure is 284 ft (86.6 m) long and 46 ft wide. If it were closed, the detour would be 47.2 mi (76 km).

Location

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CarriesSR 507
CrossesNisqually River
Location2.4 N JCT SR 510
RouteState Highway 507
CountyThurston County
StateWashington
Coordinates46.93323, -122.56091
Functional classUrban Minor Arterial

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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation7: Better than present minimum criteria
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 rating56.1 US tons
Inventory rating34.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length284 ft (86.6 m)
Longest span110 ft (33.5 m)
Deck width46 ft (14.1 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic22,357 (2023)
Projected traffic32,844 by 2039
Trucks5%
Lanes on structure3
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed47.2 mi (76 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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$5.7 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 507 over Nisqually River built?

It was built in 1987, making it 38 years old in 2025.

What condition is SR 507 over Nisqually 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 September 2023.

How much traffic does SR 507 over Nisqually River carry?

About 22,357 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is SR 507 over Nisqually River?

The structure is 284 ft (86.6 m) long with a longest span of 110 ft (33.5 m) and a deck 46 ft wide.

Who owns SR 507 over Nisqually River?

It is owned by the State Highway Agency.