US Bridges

SR 161 over Little Mashel River

Good

Pierce County, Washington · 1.8 N JCT SR 7 · Structure no. 0012982A0000000

Built
1986
39 years old
Condition
Good
inspected April 2021
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
101 ft
1 main span
Daily traffic
404
2023 count
Owner
State
State Highway Agency

About this bridge

SR 161 over Little Mashel River is a prestressed concrete stringer/multi-beam or girder carrying SR 161 over Little Mashel River in Pierce County, Washington. It was built in 1986, so it is 39 years old, younger 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 404 vehicles a day, roughly 12% of them trucks, projected to reach 477 by 2039. The structure is 101 ft (30.8 m) long and 30 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

CarriesSR 161
CrossesLittle Mashel River
Location1.8 N JCT SR 7
RouteState Highway 161
Coordinates46.85528, -122.27889
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
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 rating73 US tons
Inventory rating43 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length101 ft (30.8 m)
Longest span100 ft (30.5 m)
Deck width30 ft (9 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic404 (2023)
Projected traffic477 by 2039
Trucks12%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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$1.5 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 161 over Little Mashel River built?

It was built in 1986, making it 39 years old in 2025.

What condition is SR 161 over Little Mashel River 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 April 2021.

How much traffic does SR 161 over Little Mashel River carry?

About 404 vehicles per day (2023 count), of which roughly 12% are trucks.

How long is SR 161 over Little Mashel River?

The structure is 101 ft (30.8 m) long with a longest span of 100 ft (30.5 m) and a deck 30 ft wide.

Who owns SR 161 over Little Mashel River?

It is owned by the State Highway Agency.