US Bridges

Mountain Loop HWY over Clear Creek

Good

Snohomish County, Washington · 3.0 SE Darrington · Structure no. 086520000000000

Built
1960
65 years old, rebuilt 1984
Condition
Good
inspected June 2024
Type
Stringer/Multi-beam or Girder
Concrete Continuous
Length
125 ft
1 main span
Daily traffic
724
2021 count
Owner
County
County Highway Agency

About this bridge

Mountain Loop HWY over Clear Creek is a concrete continuous stringer/multi-beam or girder carrying Mountain Loop HWY over Clear Creek in Snohomish County, Washington. It was built in 1960 and reconstructed in 1984, so it is 65 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 724 vehicles a day, roughly 8% of them trucks, projected to reach 1,000 by 2044. The structure is 125 ft (38.1 m) long and 34 ft wide. If it were closed, the detour would be 93.8 mi (151 km).

CarriesMountain Loop HWY
CrossesClear Creek
Location3.0 SE Darrington
RouteCounty Highway 98960
Coordinates48.21878, -121.56837
Functional classRural Major Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating57 US tons
Inventory rating34 US tons

Structure

MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans1 (+2 approach)
Design loadHS 20
Structure length125 ft (38.1 m)
Longest span82 ft (25.1 m)
Deck width34 ft (10.5 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic724 (2021)
Projected traffic1,000 by 2044
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed93.8 mi (151 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$4.9 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Mountain Loop HWY over Clear Creek built?

It was built in 1960, making it 65 years old in 2025. It was reconstructed in 1984.

What condition is Mountain Loop HWY over Clear Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in June 2024.

How much traffic does Mountain Loop HWY over Clear Creek carry?

About 724 vehicles per day (2021 count), of which roughly 8% are trucks.

How long is Mountain Loop HWY over Clear Creek?

The structure is 125 ft (38.1 m) long with a longest span of 82 ft (25.1 m) and a deck 34 ft wide.

Who owns Mountain Loop HWY over Clear Creek?

It is owned by the County Highway Agency.