US Bridges

Military Road over Descutes River

Good

Thurston County, Washington · 2. NW JCT SR507 · Structure no. 081428000000000

Built
1984
41 years old
Condition
Good
inspected April 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
150 ft
1 main span
Daily traffic
911
2021 count
Owner
County
County Highway Agency

About this bridge

Military Road over Descutes River is a prestressed concrete stringer/multi-beam or girder carrying Military Road over Descutes River in Thurston County, Washington. It was built in 1984, so it is 41 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 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 911 vehicles a day, roughly 15% of them trucks, projected to reach 1,408 by 2040. The structure is 150 ft (45.7 m) long and 29 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesMilitary Road
CrossesDescutes River
Location2. NW JCT SR507
RouteCounty Highway 13350
CountyThurston County
StateWashington
Coordinates46.88041, -122.75262
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.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum 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 rating99 US tons
Inventory rating63.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length150 ft (45.7 m)
Longest span144 ft (43.9 m)
Deck width29 ft (8.7 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic911 (2021)
Projected traffic1,408 by 2040
Trucks15%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 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$5.8 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Military Road over Descutes River built?

It was built in 1984, making it 41 years old in 2025.

What condition is Military Road over Descutes River 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 April 2023.

How much traffic does Military Road over Descutes River carry?

About 911 vehicles per day (2021 count), of which roughly 15% are trucks.

How long is Military Road over Descutes River?

The structure is 150 ft (45.7 m) long with a longest span of 144 ft (43.9 m) and a deck 29 ft wide.

Who owns Military Road over Descutes River?

It is owned by the County Highway Agency.