US Bridges

HWY 100 over Multnomah Creek

Fair

Multnomah County, Oregon · At Multnomah Falls · Structure no. 04534 125 01972

Built
1914
111 years old
Condition
Fair
inspected September 2023
Type
Arch - Deck
Concrete
Length
67 ft
1 main span
Daily traffic
901
2022 count
Owner
State
State Highway Agency

About this bridge

HWY 100 over Multnomah Creek is a concrete arch - deck carrying HWY 100 over Multnomah Creek in Multnomah County, Oregon. It was built in 1914, so it is 111 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 901 vehicles a day, roughly 4% of them trucks, projected to reach 1,200 by 2042. The structure is 67 ft (20.4 m) long and 24 ft wide. If it were closed, the detour would be 14.9 mi (24 km).

Location

Open in Google Maps
CarriesHWY 100
CrossesMultnomah Creek
LocationAt Multnomah Falls
RouteState Highway 30
CountyMultnomah County
StateOregon
Coordinates45.57781, -122.11702
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
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating31.4 US tons
Inventory rating24.3 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length67 ft (20.4 m)
Longest span40 ft (12.2 m)
Deck width24 ft (7.3 m)
Roadway width22 ft (6.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic901 (2022)
Projected traffic1,200 by 2042
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.9 mi (24 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusListed on the National Register of Historic Places
Work proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$343,000
NavigationNo navigation control on waterway

Frequently asked questions

When was HWY 100 over Multnomah Creek built?

It was built in 1914, making it 111 years old in 2025.

What condition is HWY 100 over Multnomah Creek 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 September 2023.

How much traffic does HWY 100 over Multnomah Creek carry?

About 901 vehicles per day (2022 count), of which roughly 4% are trucks.

How long is HWY 100 over Multnomah Creek?

The structure is 67 ft (20.4 m) long with a longest span of 40 ft (12.2 m) and a deck 24 ft wide.

Who owns HWY 100 over Multnomah Creek?

It is owned by the State Highway Agency.