US Bridges

M RD SW over Irrigation Lateral

Fair

Grant County, Washington · M SW 0.4 S of 12 SW · Structure no. 079742000000000

Built
1958
67 years old
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
40 ft
2 main spans
Daily traffic
239
2022 count
Owner
County
County Highway Agency

About this bridge

M RD SW over Irrigation Lateral is a wood or timber stringer/multi-beam or girder carrying M RD SW over Irrigation Lateral in Grant County, Washington. It was built in 1958, so it is 67 years old, older 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 239 vehicles a day, roughly 32% of them trucks, projected to reach 300 by 2041. The structure is 40 ft (12.2 m) long and 25 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesM RD SW
CrossesIrrigation Lateral
LocationM SW 0.4 S of 12 SW
RouteCounty Highway 11850
CountyGrant County
StateWashington
Coordinates46.90857, -119.76888
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionDecember 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 rating39 US tons
Inventory rating28 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans2
Design loadH 15
Structure length40 ft (12.2 m)
Longest span20 ft (6.1 m)
Deck width25 ft (7.7 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic239 (2022)
Projected traffic300 by 2041
Trucks32%
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 statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.8 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was M RD SW over Irrigation Lateral built?

It was built in 1958, making it 67 years old in 2025.

What condition is M RD SW over Irrigation Lateral 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 December 2024.

How much traffic does M RD SW over Irrigation Lateral carry?

About 239 vehicles per day (2022 count), of which roughly 32% are trucks.

How long is M RD SW over Irrigation Lateral?

The structure is 40 ft (12.2 m) long with a longest span of 20 ft (6.1 m) and a deck 25 ft wide.

Who owns M RD SW over Irrigation Lateral?

It is owned by the County Highway Agency.