US Bridges

Hampton RD over Kamm Slough

Fair

Whatcom County, Washington · 01.6 W Northwood Road · Structure no. 088046000000000

Built
2010
15 years old
Condition
Fair
inspected February 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
145 ft
1 main span
Daily traffic
2,400
2020 count
Owner
County
County Highway Agency

About this bridge

Hampton RD over Kamm Slough is a prestressed concrete stringer/multi-beam or girder carrying Hampton RD over Kamm Slough in Whatcom County, Washington. It was built in 2010, so it is 15 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 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 2,400 vehicles a day, roughly 3% of them trucks, projected to reach 3,500 by 2042. The structure is 145 ft (44.2 m) long and 50 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesHampton RD
CrossesKamm Slough
Location01.6 W Northwood Road
RouteCounty Highway 61700
CountyWhatcom County
StateWashington
Coordinates48.94511, -122.44173
Functional classRural Minor 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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to 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 rating61.1 US tons
Inventory rating37.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHL 93
Structure length145 ft (44.2 m)
Longest span140 ft (42.7 m)
Deck width50 ft (15.2 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,400 (2020)
Projected traffic3,500 by 2042
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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$5.6 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Hampton RD over Kamm Slough built?

It was built in 2010, making it 15 years old in 2025.

What condition is Hampton RD over Kamm Slough 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 Hampton RD over Kamm Slough carry?

About 2,400 vehicles per day (2020 count), of which roughly 3% are trucks.

How long is Hampton RD over Kamm Slough?

The structure is 145 ft (44.2 m) long with a longest span of 140 ft (42.7 m) and a deck 50 ft wide.

Who owns Hampton RD over Kamm Slough?

It is owned by the County Highway Agency.