US Bridges

HWY91C to HWY1NB over SW Terwilliger Blvd.

Fair

Multnomah County, Oregon · 1.7 M S of Ross Isl. Br. · Structure no. 17176 001C29721

Built
1993
32 years old
Condition
Fair
inspected January 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
370 ft
4 main spans
Daily traffic
12,141
2022 count
Owner
State
State Highway Agency

About this bridge

HWY91C to HWY1NB over SW Terwilliger Blvd. is a concrete continuous box beam or girders - multiple carrying HWY91C to HWY1NB 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 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 12,141 vehicles a day, roughly 4% of them trucks, projected to reach 20,400 by 2042. The structure is 370 ft (112.8 m) long and 37 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesHWY91C to HWY1NB
CrossesSW Terwilliger Blvd.
Location1.7 M S of Ross Isl. Br.
RouteInterstate 99
CountyMultnomah County
StateOregon
Coordinates45.4699, -122.68654
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating22.2 US tons
Inventory rating17.2 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 25 or greater
Structure length370 ft (112.8 m)
Longest span130 ft (39.6 m)
Deck width37 ft (11.2 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic12,141 (2022)
Projected traffic20,400 by 2042
Trucks4%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesOther
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 proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was HWY91C to HWY1NB over SW Terwilliger Blvd. built?

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

What condition is HWY91C to HWY1NB 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 HWY91C to HWY1NB over SW Terwilliger Blvd. carry?

About 12,141 vehicles per day (2022 count), of which roughly 4% are trucks.

How long is HWY91C to HWY1NB over SW Terwilliger Blvd.?

The structure is 370 ft (112.8 m) long with a longest span of 130 ft (39.6 m) and a deck 37 ft wide.

Who owns HWY91C to HWY1NB over SW Terwilliger Blvd.?

It is owned by the State Highway Agency.