US Bridges

HWY 091 over Columbia Slough

Fair

Multnomah County, Oregon · 5.1 MI N of Portland Cc · Structure no. 04517 01WX00511

Built
1916
109 years old
Condition
Fair
inspected February 2024
Type
Girder and Floorbeam System
Steel
Length
683 ft
3 main spans
Daily traffic
12,202
2022 count
Owner
State
State Highway Agency

About this bridge

HWY 091 over Columbia Slough is a steel girder and floorbeam system carrying HWY 091 over Columbia Slough in Multnomah County, Oregon. It was built in 1916, so it is 109 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 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 12,202 vehicles a day, roughly 3% of them trucks, projected to reach 13,600 by 2042. The structure is 683 ft (208.1 m) long and 50 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesHWY 091
CrossesColumbia Slough
Location5.1 MI N of Portland Cc
RouteState Highway 99
CountyMultnomah County
StateOregon
Coordinates45.5897, -122.687
Functional classUrban Minor 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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2024
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 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 rating22.8 US tons
Inventory rating17.5 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel
DeckConcrete, cast-in-place
Main spans3 (+9 approach)
Design loadHS 15
Structure length683 ft (208.1 m)
Longest span78 ft (23.8 m)
Deck width50 ft (15.1 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic12,202 (2022)
Projected traffic13,600 by 2042
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway and waterway
Detour if closed1.2 mi (2 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 proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$3.5 million
NavigationNo navigation control on waterway

Frequently asked questions

When was HWY 091 over Columbia Slough built?

It was built in 1916, making it 109 years old in 2025.

What condition is HWY 091 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 February 2024.

How much traffic does HWY 091 over Columbia Slough carry?

About 12,202 vehicles per day (2022 count), of which roughly 3% are trucks.

How long is HWY 091 over Columbia Slough?

The structure is 683 ft (208.1 m) long with a longest span of 78 ft (23.8 m) and a deck 50 ft wide.

Who owns HWY 091 over Columbia Slough?

It is owned by the State Highway Agency.