US Bridges

West Union Road over Rock Creek

Fair

Washington County, Oregon · 0041 MI W 185th Avenue · Structure no. 671339117500700

Built
1978
47 years old
Condition
Fair
inspected August 2024
Type
Slab
Prestressed Concrete
Length
101 ft
3 main spans
Daily traffic
7,789
2020 count
Owner
County
County Highway Agency

About this bridge

West Union Road over Rock Creek is a prestressed concrete slab carrying West Union Road over Rock Creek in Washington County, Oregon. It was built in 1978, so it is 47 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 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 7,789 vehicles a day, roughly 15% of them trucks, projected to reach 8,590 by 2025. The structure is 101 ft (30.8 m) long and 40 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesWest Union Road
CrossesRock Creek
Location0041 MI W 185th Avenue
RouteCounty Highway C0057
CountyWashington County
StateOregon
Coordinates45.55928, -122.87626
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation6: Equal to present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating71 US tons
Inventory rating43 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans3
Design loadHS 20
Structure length101 ft (30.8 m)
Longest span34 ft (10.4 m)
Deck width40 ft (12.2 m)
Roadway width28 ft (8.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,789 (2020)
Projected traffic8,590 by 2025
Trucks15%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$517,000
NavigationNo navigation control on waterway

Frequently asked questions

When was West Union Road over Rock Creek built?

It was built in 1978, making it 47 years old in 2025.

What condition is West Union Road over Rock Creek 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 August 2024.

How much traffic does West Union Road over Rock Creek carry?

About 7,789 vehicles per day (2020 count), of which roughly 15% are trucks.

How long is West Union Road over Rock Creek?

The structure is 101 ft (30.8 m) long with a longest span of 34 ft (10.4 m) and a deck 40 ft wide.

Who owns West Union Road over Rock Creek?

It is owned by the County Highway Agency.