US Bridges

HWY 81 SB over Mollala River

Fair

Clackamas County, Oregon · In Canby · Structure no. 02061A01E 02203

Built
1963
62 years old
Condition
Fair
inspected November 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
589 ft
10 main spans
Daily traffic
11,423
2022 count
Owner
State
State Highway Agency

About this bridge

HWY 81 SB over Mollala River is a prestressed concrete stringer/multi-beam or girder carrying HWY 81 SB over Mollala River in Clackamas County, Oregon. It was built in 1963, so it is 62 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 11,423 vehicles a day, roughly 4% of them trucks, projected to reach 14,400 by 2042. The structure is 589 ft (179.6 m) long and 38 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesHWY 81 SB
CrossesMollala River
LocationIn Canby
RouteState Highway 99
CountyClackamas County
StateOregon
Coordinates45.2556, -122.7075
Functional classUrban Other Principal 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
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 inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating27.9 US tons
Inventory rating21.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans10
Design loadHS 20
Structure length589 ft (179.6 m)
Longest span81 ft (24.7 m)
Deck width38 ft (11.7 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,423 (2022)
Projected traffic14,400 by 2042
Trucks4%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 HWY 81 SB over Mollala River built?

It was built in 1963, making it 62 years old in 2025.

What condition is HWY 81 SB over Mollala 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 November 2024.

How much traffic does HWY 81 SB over Mollala River carry?

About 11,423 vehicles per day (2022 count), of which roughly 4% are trucks.

How long is HWY 81 SB over Mollala River?

The structure is 589 ft (179.6 m) long with a longest span of 81 ft (24.7 m) and a deck 38 ft wide.

Who owns HWY 81 SB over Mollala River?

It is owned by the State Highway Agency.