US Bridges

HWY 081 over Columbia Slough

Fair

Multnomah County, Oregon · 1.6 MI S of I-5 JCT · Structure no. 01377C01EX00441

Built
1934
91 years old, rebuilt 1954
Condition
Fair
inspected January 2025
Type
Girder and Floorbeam System
Steel
Length
307 ft
4 main spans
Daily traffic
17,168
2022 count
Owner
State
State Highway Agency

About this bridge

HWY 081 over Columbia Slough is a steel girder and floorbeam system carrying HWY 081 over Columbia Slough in Multnomah County, Oregon. It was built in 1934 and reconstructed in 1954, so it is 91 years old, older than the Oregon average of 49.9 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 17,168 vehicles a day, roughly 8% of them trucks, projected to reach 24,500 by 2042. The structure is 307 ft (93.6 m) long and 64 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesHWY 081
CrossesColumbia Slough
Location1.6 MI S of I-5 JCT
RouteState Highway 99
CountyMultnomah County
StateOregon
Coordinates45.58653, -122.66416
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating16.4 US tons
Inventory rating12.5 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadH 15
Structure length307 ft (93.6 m)
Longest span77 ft (23.5 m)
Deck width64 ft (19.4 m)
Roadway width53 ft (16.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic17,168 (2022)
Projected traffic24,500 by 2042
Trucks8%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed0.6 mi (1 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was HWY 081 over Columbia Slough built?

It was built in 1934, making it 91 years old in 2025. It was reconstructed in 1954.

What condition is HWY 081 over Columbia Slough 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 January 2025.

How much traffic does HWY 081 over Columbia Slough carry?

About 17,168 vehicles per day (2022 count), of which roughly 8% are trucks.

How long is HWY 081 over Columbia Slough?

The structure is 307 ft (93.6 m) long with a longest span of 77 ft (23.5 m) and a deck 64 ft wide.

Who owns HWY 081 over Columbia Slough?

It is owned by the State Highway Agency.