US Bridges

I-405 (hwy 061) over Conns 1 & 2

Fair

Multnomah County, Oregon · W Marquam Interchange · Structure no. 08591F061 00048

Built
1966
59 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
1,140 ft
3 main spans
Daily traffic
42,482
2022 count
Owner
State
State Highway Agency

About this bridge

I-405 (hwy 061) over Conns 1 & 2 is a steel stringer/multi-beam or girder carrying I-405 (hwy 061) over Conns 1 & 2 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 42,482 vehicles a day, roughly 6% of them trucks, projected to reach 45,550 by 2042. The structure is 1,140 ft (347.5 m) long and 37 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-405 (hwy 061)
CrossesConns 1 & 2
LocationW Marquam Interchange
RouteInterstate 405
CountyMultnomah County
StateOregon
Coordinates45.50456, -122.67442
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 evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating21.1 US tons
Inventory rating16.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3 (+11 approach)
Design loadHS 20
Structure length1,140 ft (347.5 m)
Longest span186 ft (56.7 m)
Deck width37 ft (11.3 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deck19 ft (5.7 m)

Traffic and service

Average daily traffic42,482 (2022)
Projected traffic45,550 by 2042
Trucks6%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed1.2 mi (2 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 proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$7 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-405 (hwy 061) over Conns 1 & 2 built?

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

What condition is I-405 (hwy 061) over Conns 1 & 2 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-405 (hwy 061) over Conns 1 & 2 carry?

About 42,482 vehicles per day (2022 count), of which roughly 6% are trucks.

How long is I-405 (hwy 061) over Conns 1 & 2?

The structure is 1,140 ft (347.5 m) long with a longest span of 186 ft (56.7 m) and a deck 37 ft wide.

Who owns I-405 (hwy 061) over Conns 1 & 2?

It is owned by the State Highway Agency.