US Bridges

Alderson RD over Terrell Creek

Fair

Whatcom County, Washington · 0.01 W Birchbay DR · Structure no. 085799000000000

Built
1987
38 years old
Condition
Fair
inspected April 2023
Type
Channel Beam
Steel
Length
50 ft
2 main spans
Daily traffic
2,184
2021 count
Owner
County
County Highway Agency

About this bridge

Alderson RD over Terrell Creek is a steel channel beam carrying Alderson RD over Terrell Creek in Whatcom County, Washington. It was built in 1987, so it is 38 years old, younger than the Washington average of 49.8 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 2,184 vehicles a day, roughly 2% of them trucks, projected to reach 4,000 by 2043. The structure is 50 ft (15.2 m) long and 47 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesAlderson RD
CrossesTerrell Creek
Location0.01 W Birchbay DR
RouteCounty Highway 22450
CountyWhatcom County
StateWashington
Coordinates48.91771, -122.74547
Functional classUrban 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
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 rating33.2 US tons
Inventory rating23.6 US tons

Structure

Structure typeChannel Beam
MaterialSteel
DeckOther
Main spans2
Design loadHS 20
Structure length50 ft (15.2 m)
Longest span30 ft (9.1 m)
Deck width47 ft (14.3 m)
Roadway width37 ft (11.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,184 (2021)
Projected traffic4,000 by 2043
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$2.2 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Alderson RD over Terrell Creek built?

It was built in 1987, making it 38 years old in 2025.

What condition is Alderson RD over Terrell 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 April 2023.

How much traffic does Alderson RD over Terrell Creek carry?

About 2,184 vehicles per day (2021 count), of which roughly 2% are trucks.

How long is Alderson RD over Terrell Creek?

The structure is 50 ft (15.2 m) long with a longest span of 30 ft (9.1 m) and a deck 47 ft wide.

Who owns Alderson RD over Terrell Creek?

It is owned by the County Highway Agency.