US Bridges

Peninsula Drive over St.Clair Lake

Fair

Thurston County, Washington · .1 M NW ST Cl DR · Structure no. 084162000000000

Built
1963
62 years old
Condition
Fair
inspected July 2023
Type
Tee Beam
Prestressed Concrete
Length
54 ft
3 main spans
Daily traffic
329
2021 count
Owner
County
County Highway Agency

About this bridge

Peninsula Drive over St.Clair Lake is a prestressed concrete tee beam carrying Peninsula Drive over St.Clair Lake in Thurston County, Washington. It was built in 1963, so it is 62 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 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 329 vehicles a day, roughly 15% of them trucks, projected to reach 489 by 2043. The structure is 54 ft (16.5 m) long and 22 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesPeninsula Drive
CrossesSt.Clair Lake
Location.1 M NW ST Cl DR
RouteCounty Highway 13935
CountyThurston County
StateWashington
Coordinates46.99687, -122.72057
Functional classUrban 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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating76.9 US tons
Inventory rating60 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans3
Design loadHS 20
Structure length54 ft (16.5 m)
Longest span24 ft (7.3 m)
Deck width22 ft (6.6 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic329 (2021)
Projected traffic489 by 2043
Trucks15%
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$2.3 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Peninsula Drive over St.Clair Lake built?

It was built in 1963, making it 62 years old in 2025.

What condition is Peninsula Drive over St.Clair Lake 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 2023.

How much traffic does Peninsula Drive over St.Clair Lake carry?

About 329 vehicles per day (2021 count), of which roughly 15% are trucks.

How long is Peninsula Drive over St.Clair Lake?

The structure is 54 ft (16.5 m) long with a longest span of 24 ft (7.3 m) and a deck 22 ft wide.

Who owns Peninsula Drive over St.Clair Lake?

It is owned by the County Highway Agency.