US Bridges

Or 99W (hwy 001W) over SW Vermont ST Viaduct

FairPosted for load

Multnomah County, Oregon · 0.3 M S of HWY 40 · Structure no. 01984 01W 00350

Built
1934
91 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
531 ft
18 main spans
Daily traffic
14,057
2022 count
Owner
State
State Highway Agency

About this bridge

Or 99W (hwy 001W) over SW Vermont ST Viaduct is a wood or timber stringer/multi-beam or girder carrying Or 99W (hwy 001W) over SW Vermont ST Viaduct in Multnomah County, Oregon. It was built in 1934, so it is 91 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 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 14,057 vehicles a day, roughly 1% of them trucks, projected to reach 20,300 by 2042. The structure is 531 ft (161.8 m) long and 57 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesOr 99W (hwy 001W)
CrossesSW Vermont ST Viaduct
Location0.3 M S of HWY 40
RouteState Highway 99
CountyMultnomah County
StateOregon
Coordinates45.47613, -122.67964
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating29.3 US tons
Inventory rating22.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckConcrete, cast-in-place
Main spans18
Design loadH 15
Structure length531 ft (161.8 m)
Longest span38 ft (11.6 m)
Deck width57 ft (17.5 m)
Roadway width48 ft (14.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic14,057 (2022)
Projected traffic20,300 by 2042
Trucks1%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesOther
Detour if closed1.2 mi (2 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$3 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was Or 99W (hwy 001W) over SW Vermont ST Viaduct built?

It was built in 1934, making it 91 years old in 2025.

What condition is Or 99W (hwy 001W) over SW Vermont ST Viaduct 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 2023.

How much traffic does Or 99W (hwy 001W) over SW Vermont ST Viaduct carry?

About 14,057 vehicles per day (2022 count), of which roughly 1% are trucks.

How long is Or 99W (hwy 001W) over SW Vermont ST Viaduct?

The structure is 531 ft (161.8 m) long with a longest span of 38 ft (11.6 m) and a deck 57 ft wide.

Who owns Or 99W (hwy 001W) over SW Vermont ST Viaduct?

It is owned by the State Highway Agency.