US Bridges

1W to HWY 1 NB over SW Terwilliger Blvd.

Fair

Multnomah County, Oregon · 1.7 M S of Ross Isl. Br. · Structure no. 17064 001C29705

Built
1993
32 years old
Condition
Fair
inspected January 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
870 ft
6 main spans
Daily traffic
9,194
2022 count
Owner
State
State Highway Agency

About this bridge

1W to HWY 1 NB over SW Terwilliger Blvd. is a prestressed concrete continuous box beam or girders - multiple carrying 1W to HWY 1 NB over SW Terwilliger Blvd. in Multnomah County, Oregon. It was built in 1993, so it is 32 years old, younger 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 9,194 vehicles a day, roughly 1% of them trucks, projected to reach 25,500 by 2036. The structure is 870 ft (265.2 m) long and 29 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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Carries1W to HWY 1 NB
CrossesSW Terwilliger Blvd.
Location1.7 M S of Ross Isl. Br.
RouteState Highway 99
CountyMultnomah County
StateOregon
Coordinates45.4699, -122.6874
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.
Substructure7 GoodSome minor problems.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating21.1 US tons
Inventory rating16.1 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHS 25 or greater
Structure length870 ft (265.2 m)
Longest span166 ft (50.6 m)
Deck width29 ft (8.7 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deck18 ft (5.6 m)

Traffic and service

Average daily traffic9,194 (2022)
Projected traffic25,500 by 2036
Trucks1%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemYes

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$4.2 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was 1W to HWY 1 NB over SW Terwilliger Blvd. built?

It was built in 1993, making it 32 years old in 2025.

What condition is 1W to HWY 1 NB over SW Terwilliger Blvd. 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 2024.

How much traffic does 1W to HWY 1 NB over SW Terwilliger Blvd. carry?

About 9,194 vehicles per day (2022 count), of which roughly 1% are trucks.

How long is 1W to HWY 1 NB over SW Terwilliger Blvd.?

The structure is 870 ft (265.2 m) long with a longest span of 166 ft (50.6 m) and a deck 29 ft wide.

Who owns 1W to HWY 1 NB over SW Terwilliger Blvd.?

It is owned by the State Highway Agency.