US Bridges

County RD 20 over South Umpqua River

Fair

Douglas County, Oregon · 1.0 MI NE of Riddle · Structure no. 20358 000 082

Built
2009
16 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
588 ft
3 main spans
Daily traffic
10,697
2020 count
Owner
County
County Highway Agency

About this bridge

County RD 20 over South Umpqua River is a steel continuous stringer/multi-beam or girder carrying County RD 20 over South Umpqua River in Douglas County, Oregon. It was built in 2009, so it is 16 years old, younger than the Oregon average of 49.9 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 10,697 vehicles a day, roughly 15% of them trucks, projected to reach 12,067 by 2025. The structure is 588 ft (179.2 m) long and 44 ft wide. If it were closed, the detour would be 7.5 mi (12 km).

Location

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CarriesCounty RD 20
CrossesSouth Umpqua River
Location1.0 MI NE of Riddle
RouteCounty Highway 0A385
CountyDouglas County
StateOregon
Coordinates42.97334, -123.34663
Functional classRural Minor Arterial

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 protection8 Very GoodNo problems noted.
Last inspectionJune 2023
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 rating41.1 US tons
Inventory rating31.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length588 ft (179.2 m)
Longest span218 ft (66.4 m)
Deck width44 ft (13.3 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,697 (2020)
Projected traffic12,067 by 2025
Trucks15%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed7.5 mi (12 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was County RD 20 over South Umpqua River built?

It was built in 2009, making it 16 years old in 2025.

What condition is County RD 20 over South Umpqua River 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 June 2023.

How much traffic does County RD 20 over South Umpqua River carry?

About 10,697 vehicles per day (2020 count), of which roughly 15% are trucks.

How long is County RD 20 over South Umpqua River?

The structure is 588 ft (179.2 m) long with a longest span of 218 ft (66.4 m) and a deck 44 ft wide.

Who owns County RD 20 over South Umpqua River?

It is owned by the County Highway Agency.