US Bridges

I-5 (hwy 001) over Col. Slough & HWY 1 Conn

Fair

Multnomah County, Oregon · 2.2 MI S of Interstate Br · Structure no. 08883 001 30622

Built
1964
61 years old
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
1,239 ft
12 main spans
Daily traffic
85,841
2022 count
Owner
State
State Highway Agency

About this bridge

I-5 (hwy 001) over Col. Slough & HWY 1 Conn is a prestressed concrete continuous stringer/multi-beam or girder carrying I-5 (hwy 001) over Col. Slough & HWY 1 Conn in Multnomah County, Oregon. It was built in 1964, so it is 61 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 85,841 vehicles a day, roughly 9% of them trucks, projected to reach 87,900 by 2042. The structure is 1,239 ft (377.6 m) long and 115 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-5 (hwy 001)
CrossesCol. Slough & HWY 1 Conn
Location2.2 MI S of Interstate Br
RouteInterstate 5
CountyMultnomah County
StateOregon
Coordinates45.58871, -122.68129
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.
Channel and channel protection7 GoodSome minor problems.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating23.3 US tons
Inventory rating17.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans12 (+5 approach)
Design loadHS 20
Structure length1,239 ft (377.6 m)
Longest span104 ft (31.7 m)
Deck width115 ft (35.2 m)
Roadway width110 ft (33.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic85,841 (2022)
Projected traffic87,900 by 2042
Trucks9%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway and waterway
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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was I-5 (hwy 001) over Col. Slough & HWY 1 Conn built?

It was built in 1964, making it 61 years old in 2025.

What condition is I-5 (hwy 001) over Col. Slough & HWY 1 Conn 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 December 2024.

How much traffic does I-5 (hwy 001) over Col. Slough & HWY 1 Conn carry?

About 85,841 vehicles per day (2022 count), of which roughly 9% are trucks.

How long is I-5 (hwy 001) over Col. Slough & HWY 1 Conn?

The structure is 1,239 ft (377.6 m) long with a longest span of 104 ft (31.7 m) and a deck 115 ft wide.

Who owns I-5 (hwy 001) over Col. Slough & HWY 1 Conn?

It is owned by the State Highway Agency.