US Bridges

Or 99W(HWY 91)NB over Harbor Drive Viaduct

Fair

Multnomah County, Oregon · Near W End Ross Isl. Br. · Structure no. 05195A01W 00193

Built
1949
76 years old
Condition
Fair
inspected February 2024
Type
Tee Beam
Concrete Continuous
Length
514 ft
13 main spans
Daily traffic
11,470
2022 count
Owner
State
State Highway Agency

About this bridge

Or 99W(HWY 91)NB over Harbor Drive Viaduct is a concrete continuous tee beam carrying Or 99W(HWY 91)NB over Harbor Drive Viaduct in Multnomah County, Oregon. It was built in 1949, so it is 76 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 11,470 vehicles a day, roughly 1% of them trucks, projected to reach 14,050 by 2042. The structure is 514 ft (156.7 m) long and 34 ft wide.

Location

Open in Google Maps
CarriesOr 99W(HWY 91)NB
CrossesHarbor Drive Viaduct
LocationNear W End Ross Isl. Br.
RouteState Highway 99
CountyMultnomah County
StateOregon
Coordinates45.49554, -122.67778
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 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 alignment6: Equal to present minimum criteria
Operating rating19.3 US tons
Inventory rating15 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans13
Design loadH 15
Structure length514 ft (156.7 m)
Longest span42 ft (12.8 m)
Deck width34 ft (10.3 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,470 (2022)
Projected traffic14,050 by 2042
Trucks1%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesOther
Detour if closed—
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$2.6 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was Or 99W(HWY 91)NB over Harbor Drive Viaduct built?

It was built in 1949, making it 76 years old in 2025.

What condition is Or 99W(HWY 91)NB over Harbor Drive 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 February 2024.

How much traffic does Or 99W(HWY 91)NB over Harbor Drive Viaduct carry?

About 11,470 vehicles per day (2022 count), of which roughly 1% are trucks.

How long is Or 99W(HWY 91)NB over Harbor Drive Viaduct?

The structure is 514 ft (156.7 m) long with a longest span of 42 ft (12.8 m) and a deck 34 ft wide.

Who owns Or 99W(HWY 91)NB over Harbor Drive Viaduct?

It is owned by the State Highway Agency.