US Bridges

I-5 (hwy 001) SB over Marquam Ramp SB

Fair

Multnomah County, Oregon · West Marquam Interchange · Structure no. 08591C001 30010

Built
1966
59 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
1,898 ft
14 main spans
Daily traffic
70,324
2022 count
Owner
State
State Highway Agency

About this bridge

I-5 (hwy 001) SB over Marquam Ramp SB is a steel stringer/multi-beam or girder carrying I-5 (hwy 001) SB over Marquam Ramp SB in Multnomah County, Oregon. It was built in 1966, so it is 59 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 70,324 vehicles a day, roughly 10% of them trucks, projected to reach 73,900 by 2042. The structure is 1,898 ft (578.6 m) long and 37 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

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CarriesI-5 (hwy 001) SB
CrossesMarquam Ramp SB
LocationWest Marquam Interchange
RouteInterstate 5
CountyMultnomah County
StateOregon
Coordinates45.5056, -122.6735
Functional classUrban Principal Arterial - Interstate

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.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating13.6 US tons
Inventory rating10.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans14 (+1 approach)
Design loadHS 20
Structure length1,898 ft (578.6 m)
Longest span190 ft (57.8 m)
Deck width37 ft (11.3 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deck16 ft (4.9 m)

Traffic and service

Average daily traffic70,324 (2022)
Projected traffic73,900 by 2042
Trucks10%
Lanes on structure2
Traffic directionOne-way traffic
CarriesThird level (interchange)
CrossesHighway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$13 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-5 (hwy 001) SB over Marquam Ramp SB built?

It was built in 1966, making it 59 years old in 2025.

What condition is I-5 (hwy 001) SB over Marquam Ramp SB 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 September 2024.

How much traffic does I-5 (hwy 001) SB over Marquam Ramp SB carry?

About 70,324 vehicles per day (2022 count), of which roughly 10% are trucks.

How long is I-5 (hwy 001) SB over Marquam Ramp SB?

The structure is 1,898 ft (578.6 m) long with a longest span of 190 ft (57.8 m) and a deck 37 ft wide.

Who owns I-5 (hwy 001) SB over Marquam Ramp SB?

It is owned by the State Highway Agency.