US Bridges

County RD 721 over South Santiam River

Fair

Linn County, Oregon · 0.25 NE of Waterloo · Structure no. 02287A072100480

Built
1961
64 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
349 ft
3 main spans
Daily traffic
1,854
2021 count
Owner
County
County Highway Agency

About this bridge

County RD 721 over South Santiam River is a steel continuous stringer/multi-beam or girder carrying County RD 721 over South Santiam River in Linn County, Oregon. It was built in 1961, so it is 64 years old, older 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 5 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 1,854 vehicles a day, roughly 10% of them trucks, projected to reach 2,575 by 2041. The structure is 349 ft (106.4 m) long and 33 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesCounty RD 721
CrossesSouth Santiam River
Location0.25 NE of Waterloo
RouteCounty Highway 0
CountyLinn County
StateOregon
Coordinates44.49749, -122.82103
Functional classRural Major 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating47.2 US tons
Inventory rating36.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length349 ft (106.4 m)
Longest span160 ft (48.8 m)
Deck width33 ft (10.1 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,854 (2021)
Projected traffic2,575 by 2041
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed8.1 mi (13 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was County RD 721 over South Santiam River built?

It was built in 1961, making it 64 years old in 2025.

What condition is County RD 721 over South Santiam 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 August 2023.

How much traffic does County RD 721 over South Santiam River carry?

About 1,854 vehicles per day (2021 count), of which roughly 10% are trucks.

How long is County RD 721 over South Santiam River?

The structure is 349 ft (106.4 m) long with a longest span of 160 ft (48.8 m) and a deck 33 ft wide.

Who owns County RD 721 over South Santiam River?

It is owned by the County Highway Agency.