US Bridges

Thorn Hollow Road over Whetstone Creek

Good

Columbia County, Washington · 0.03 Miles SE JCT 25860 · Structure no. 088819000000000

Built
2015
10 years old
Condition
Good
inspected October 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
42 ft
1 main span
Daily traffic
200
2020 count
Owner
County
County Highway Agency

About this bridge

Thorn Hollow Road over Whetstone Creek is a prestressed concrete stringer/multi-beam or girder carrying Thorn Hollow Road over Whetstone Creek in Columbia County, Washington. It was built in 2015, so it is 10 years old, younger 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 200 vehicles a day, roughly 15% of them trucks, projected to reach 350 by 2042. The structure is 42 ft (12.8 m) long and 28 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

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CarriesThorn Hollow Road
CrossesWhetstone Creek
Location0.03 Miles SE JCT 25860
RouteCounty Highway 92180
CountyColumbia County
StateWashington
Coordinates46.35216, -118.07661
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
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation8: Equal to present desirable criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating68.6 US tons
Inventory rating52.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadHL 93
Structure length42 ft (12.8 m)
Longest span40 ft (12.2 m)
Deck width28 ft (8.5 m)
Roadway width26 ft (8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic200 (2020)
Projected traffic350 by 2042
Trucks15%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.7 mi (14 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost$598,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Thorn Hollow Road over Whetstone Creek built?

It was built in 2015, making it 10 years old in 2025.

What condition is Thorn Hollow Road over Whetstone 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 October 2024.

How much traffic does Thorn Hollow Road over Whetstone Creek carry?

About 200 vehicles per day (2020 count), of which roughly 15% are trucks.

How long is Thorn Hollow Road over Whetstone Creek?

The structure is 42 ft (12.8 m) long with a longest span of 40 ft (12.2 m) and a deck 28 ft wide.

Who owns Thorn Hollow Road over Whetstone Creek?

It is owned by the County Highway Agency.