US Bridges

Steelhead Drive So over Mission Creek

Fair

Mason County, Washington · 0.04 W Mission CR RD · Structure no. 085885000000000

Built
1990
35 years old
Condition
Fair
inspected August 2023
Type
Tee Beam
Prestressed Concrete
Length
58 ft
1 main span
Daily traffic
950
2020 count
Owner
County
County Highway Agency

About this bridge

Steelhead Drive So over Mission Creek is a prestressed concrete tee beam carrying Steelhead Drive So over Mission Creek in Mason County, Washington. It was built in 1990, so it is 35 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 950 vehicles a day, roughly 1% of them trucks, projected to reach 350 by 2040. The structure is 58 ft (17.8 m) long and 30 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesSteelhead Drive So
CrossesMission Creek
Location0.04 W Mission CR RD
RouteCounty Highway 84110
CountyMason County
StateWashington
Coordinates47.45314, -122.86767
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
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 adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating30 US tons
Inventory rating23 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length58 ft (17.8 m)
Longest span56 ft (17.1 m)
Deck width30 ft (9.1 m)
Roadway width28 ft (8.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic950 (2020)
Projected traffic350 by 2040
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$50,000 (2070 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Steelhead Drive So over Mission Creek built?

It was built in 1990, making it 35 years old in 2025.

What condition is Steelhead Drive So over Mission Creek 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 August 2023.

How much traffic does Steelhead Drive So over Mission Creek carry?

About 950 vehicles per day (2020 count), of which roughly 1% are trucks.

How long is Steelhead Drive So over Mission Creek?

The structure is 58 ft (17.8 m) long with a longest span of 56 ft (17.1 m) and a deck 30 ft wide.

Who owns Steelhead Drive So over Mission Creek?

It is owned by the County Highway Agency.