US Bridges

NW Maywood DR over B-18 Semi-Viaduct

FairPosted for load

Multnomah County, Oregon · At NW Melinda Ave · Structure no. 25B18 000

Built
1934
91 years old
Condition
Fair
inspected September 2024
Type
Frame
Concrete Continuous
Length
111 ft
9 main spans
Daily traffic
709
2020 count
Owner
City
City or Municipal Highway Agency

About this bridge

NW Maywood DR over B-18 Semi-Viaduct is a concrete continuous frame carrying NW Maywood DR over B-18 Semi-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 6 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 709 vehicles a day, roughly 1% of them trucks, projected to reach 782 by 2025. The structure is 111 ft (33.8 m) long and 15 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesNW Maywood DR
CrossesB-18 Semi-Viaduct
LocationAt NW Melinda Ave
RouteCity Street C0000
CountyMultnomah County
StateOregon
Coordinates45.52739, -122.70592
Functional classUrban Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourBridge not over waterway
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating16.1 US tons
Inventory rating12.5 US tons

Structure

Structure typeFrame
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans9
Design loadH 15
Structure length111 ft (33.8 m)
Longest span13 ft (4 m)
Deck width15 ft (4.7 m)
Roadway width24 ft (7.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic709 (2020)
Projected traffic782 by 2025
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesOther
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 NW Maywood DR over B-18 Semi-Viaduct built?

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

What condition is NW Maywood DR over B-18 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 Maywood DR over B-18 Semi-Viaduct carry?

About 709 vehicles per day (2020 count), of which roughly 1% are trucks.

How long is NW Maywood DR over B-18 Semi-Viaduct?

The structure is 111 ft (33.8 m) long with a longest span of 13 ft (4 m) and a deck 15 ft wide.

Who owns NW Maywood DR over B-18 Semi-Viaduct?

It is owned by the City or Municipal Highway Agency.