US Bridges

HWY 161 over Molalla River

Good

Clackamas County, Oregon · 2.7 MI NE of Molalla · Structure no. 17355 161 01541

Built
1996
29 years old
Condition
Good
inspected June 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
318 ft
2 main spans
Daily traffic
6,812
2022 count
Owner
State
State Highway Agency

About this bridge

HWY 161 over Molalla River is a prestressed concrete box beam or girders - multiple carrying HWY 161 over Molalla River in Clackamas County, Oregon. It was built in 1996, so it is 29 years old, younger than the Oregon average of 49.9 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 6,812 vehicles a day, roughly 15% of them trucks, projected to reach 7,600 by 2042. The structure is 318 ft (96.9 m) long and 43 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesHWY 161
CrossesMolalla River
Location2.7 MI NE of Molalla
RouteState Highway 211
CountyClackamas County
StateOregon
Coordinates45.16163, -122.53513
Functional classRural Minor Arterial

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.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJune 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 adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating41.1 US tons
Inventory rating31.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 25 or greater
Structure length318 ft (96.9 m)
Longest span159 ft (48.5 m)
Deck width43 ft (13.2 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,812 (2022)
Projected traffic7,600 by 2042
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

OwnerState Highway Agency
Maintained byState 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 HWY 161 over Molalla River built?

It was built in 1996, making it 29 years old in 2025.

What condition is HWY 161 over Molalla 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 June 2023.

How much traffic does HWY 161 over Molalla River carry?

About 6,812 vehicles per day (2022 count), of which roughly 15% are trucks.

How long is HWY 161 over Molalla River?

The structure is 318 ft (96.9 m) long with a longest span of 159 ft (48.5 m) and a deck 43 ft wide.

Who owns HWY 161 over Molalla River?

It is owned by the State Highway Agency.