US Bridges

HWY 100 over Mosier Creek

FairPosted for load

Wasco County, Oregon · In Mosier · Structure no. 00498 292 00064

Built
1920
105 years old
Condition
Fair
inspected February 2024
Type
Arch - Deck
Concrete
Length
182 ft
1 main span
Daily traffic
765
2022 count
Owner
State
State Highway Agency

About this bridge

HWY 100 over Mosier Creek is a concrete arch - deck carrying HWY 100 over Mosier Creek in Wasco County, Oregon. It was built in 1920, so it is 105 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 765 vehicles a day, roughly 8% of them trucks, projected to reach 1,000 by 2042. The structure is 182 ft (55.5 m) long and 23 ft wide. If it were closed, the detour would be 14.3 mi (23 km).

Location

Open in Google Maps
CarriesHWY 100
CrossesMosier Creek
LocationIn Mosier
RouteState Highway 30
CountyWasco County
StateOregon
Coordinates45.68466, -121.39442
Functional classRural Major Collector

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating23.9 US tons
Inventory rating18.5 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1 (+6 approach)
Design loadH 15
Structure length182 ft (55.5 m)
Longest span110 ft (33.5 m)
Deck width23 ft (7 m)
Roadway width19 ft (5.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic765 (2022)
Projected traffic1,000 by 2042
Trucks8%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed14.3 mi (23 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusListed on the National Register of Historic Places
Work proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$932,000
NavigationNo navigation control on waterway

Frequently asked questions

When was HWY 100 over Mosier Creek built?

It was built in 1920, making it 105 years old in 2025.

What condition is HWY 100 over Mosier 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 February 2024.

How much traffic does HWY 100 over Mosier Creek carry?

About 765 vehicles per day (2022 count), of which roughly 8% are trucks.

How long is HWY 100 over Mosier Creek?

The structure is 182 ft (55.5 m) long with a longest span of 110 ft (33.5 m) and a deck 23 ft wide.

Who owns HWY 100 over Mosier Creek?

It is owned by the State Highway Agency.