US Bridges

NW Front Ave over B-77 Semi-Viaduct

Fair

Multnomah County, Oregon · At Pop Terminal 1 · Structure no. 25B77 000 B-77

Built
1924
101 years old
Condition
Fair
inspected September 2024
Type
Tee Beam
Concrete Continuous
Length
220 ft
15 main spans
Daily traffic
11,101
2020 count
Owner
City
City or Municipal Highway Agency

About this bridge

NW Front Ave over B-77 Semi-Viaduct is a concrete continuous tee beam carrying NW Front Ave over B-77 Semi-Viaduct in Multnomah County, Oregon. It was built in 1924, so it is 101 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.

It carries about 11,101 vehicles a day, roughly 10% of them trucks, projected to reach 14,779 by 2025. The structure is 220 ft (67.1 m) long and 22 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesNW Front Ave
CrossesB-77 Semi-Viaduct
LocationAt Pop Terminal 1
RouteCity Street 0
CountyMultnomah County
StateOregon
Coordinates45.53959, -122.6912
Functional classUrban Minor 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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating17.2 US tons
Inventory rating13.2 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans15
Design loadUnknown
Structure length220 ft (67.1 m)
Longest span15 ft (4.6 m)
Deck width22 ft (6.7 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,101 (2020)
Projected traffic14,779 by 2025
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed0.6 mi (1 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was NW Front Ave over B-77 Semi-Viaduct built?

It was built in 1924, making it 101 years old in 2025.

What condition is NW Front Ave over B-77 Semi-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 2024.

How much traffic does NW Front Ave over B-77 Semi-Viaduct carry?

About 11,101 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is NW Front Ave over B-77 Semi-Viaduct?

The structure is 220 ft (67.1 m) long with a longest span of 15 ft (4.6 m) and a deck 22 ft wide.

Who owns NW Front Ave over B-77 Semi-Viaduct?

It is owned by the City or Municipal Highway Agency.