US Bridges

SR509 over Thea Foss Watrway & D ST

Fair

Pierce County, Washington · 0.1 N JCT I-705 · Structure no. 0014507A0000000

Built
1996
29 years old
Condition
Fair
inspected September 2023
Type
Stayed Girder
Prestressed Concrete Continuous
Length
992 ft
2 main spans
Daily traffic
18,728
2023 count
Owner
State
State Highway Agency

About this bridge

SR509 over Thea Foss Watrway & D ST is a prestressed concrete continuous stayed girder carrying SR509 over Thea Foss Watrway & D ST in Pierce County, Washington. It was built in 1996, so it is 29 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 18,728 vehicles a day, roughly 5% of them trucks, projected to reach 27,514 by 2039. The structure is 992 ft (302.4 m) long and 95 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesSR509
CrossesThea Foss Watrway & D ST
Location0.1 N JCT I-705
RouteState Highway 509
CountyPierce County
StateWashington
Coordinates47.24333, -122.43378
Functional classUrban Principal Arterial - Other Freeway or Expressway

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating23.3 US tons
Inventory rating13.9 US tons

Structure

Structure typeStayed Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2 (+2 approach)
Design loadHS 25 or greater
Structure length992 ft (302.4 m)
Longest span350 ft (106.7 m)
Deck width95 ft (28.9 m)
Roadway width72 ft (21.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,728 (2023)
Projected traffic27,514 by 2039
Trucks5%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and waterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$34.9 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR509 over Thea Foss Watrway & D ST built?

It was built in 1996, making it 29 years old in 2025.

What condition is SR509 over Thea Foss Watrway & D ST 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 SR509 over Thea Foss Watrway & D ST carry?

About 18,728 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is SR509 over Thea Foss Watrway & D ST?

The structure is 992 ft (302.4 m) long with a longest span of 350 ft (106.7 m) and a deck 95 ft wide.

Who owns SR509 over Thea Foss Watrway & D ST?

It is owned by the State Highway Agency.