US Bridges

SR 161 over Tanwax CR

Good

Pierce County, Washington · 10.2 N JCT SR 7 · Structure no. 002000740000000

Built
1900
125 years old
Condition
Good
inspected September 2023
Type
Culvert
Concrete Continuous
Length
21 ft
2 main spans
Daily traffic
7,089
2023 count
Owner
State
State Highway Agency

About this bridge

SR 161 over Tanwax CR is a concrete continuous culvert carrying SR 161 over Tanwax CR in Pierce County, Washington. It was built in 1900, so it is 125 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 7,089 vehicles a day, roughly 7% of them trucks, projected to reach 10,079 by 2039. The structure is 21 ft (6.4 m) long. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesSR 161
CrossesTanwax CR
Location10.2 N JCT SR 7
RouteState Highway 161
CountyPierce County
StateWashington
Coordinates46.94102, -122.28111
Functional classRural Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert7 GoodSome minor problems.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating45 US tons
Inventory rating27 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadUnknown
Structure length21 ft (6.4 m)
Longest span9 ft (2.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,089 (2023)
Projected traffic10,079 by 2039
Trucks7%
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

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$339,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 161 over Tanwax CR built?

It was built in 1900, making it 125 years old in 2025.

What condition is SR 161 over Tanwax CR in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in September 2023.

How much traffic does SR 161 over Tanwax CR carry?

About 7,089 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is SR 161 over Tanwax CR?

The structure is 21 ft (6.4 m) long with a longest span of 9 ft (2.7 m).

Who owns SR 161 over Tanwax CR?

It is owned by the State Highway Agency.