US Bridges

SR 173 over Columbia R

Fair

Douglas County, Washington · 10.5 N JCT SR 17 · Structure no. 0008566A0000000

Built
1970
55 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
1,633 ft
10 main spans
Daily traffic
3,767
2023 count
Owner
State
State Highway Agency

About this bridge

SR 173 over Columbia R is a steel continuous stringer/multi-beam or girder carrying SR 173 over Columbia R in Douglas County, Washington. It was built in 1970, so it is 55 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 5 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 3,767 vehicles a day, roughly 5% of them trucks, projected to reach 4,635 by 2039. The structure is 1,633 ft (497.7 m) long and 38 ft wide. If it were closed, the detour would be 24.9 mi (40 km).

Location

Open in Google Maps
CarriesSR 173
CrossesColumbia R
Location10.5 N JCT SR 17
RouteState Highway 173
CountyDouglas County
StateWashington
Coordinates48.08481, -119.78083
Functional classRural Major Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating40 US tons
Inventory rating24 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans10
Design loadHS 20
Structure length1,633 ft (497.7 m)
Longest span343 ft (104.5 m)
Deck width38 ft (11.5 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,767 (2023)
Projected traffic4,635 by 2039
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed24.9 mi (40 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$24.8 million (2022 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was SR 173 over Columbia R built?

It was built in 1970, making it 55 years old in 2025.

What condition is SR 173 over Columbia R 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 SR 173 over Columbia R carry?

About 3,767 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is SR 173 over Columbia R?

The structure is 1,633 ft (497.7 m) long with a longest span of 343 ft (104.5 m) and a deck 38 ft wide.

Who owns SR 173 over Columbia R?

It is owned by the State Highway Agency.