US Bridges

Otis ST over Mill Creek

FairPosted for load

Walla Walla County, Washington · Otis and Mill CR · Structure no. 085361000000000

Built
1923
102 years old
Condition
Fair
inspected September 2023
Type
Tee Beam
Concrete
Length
52 ft
1 main span
Daily traffic
2,296
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Otis ST over Mill Creek is a concrete tee beam carrying Otis ST over Mill Creek in Walla Walla County, Washington. It was built in 1923, so it is 102 years old, older than the Washington average of 49.8 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. Its operating status is: posted for load restriction.

It carries about 2,296 vehicles a day, roughly 5% of them trucks, projected to reach 6,000 by 2043. The structure is 52 ft (15.8 m) long and 52 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesOtis ST
CrossesMill Creek
LocationOtis and Mill CR
RouteCity Street 1365
CountyWalla Walla County
StateWashington
Coordinates46.06836, -118.32808
Functional classUrban Local

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.
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 protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
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 rating20 US tons
Inventory rating15 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length52 ft (15.8 m)
Longest span46 ft (14 m)
Deck width52 ft (15.8 m)
Roadway width28 ft (8.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,296 (2023)
Projected traffic6,000 by 2043
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$2.2 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Otis ST over Mill Creek built?

It was built in 1923, making it 102 years old in 2025.

What condition is Otis ST over Mill 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 Otis ST over Mill Creek carry?

About 2,296 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Otis ST over Mill Creek?

The structure is 52 ft (15.8 m) long with a longest span of 46 ft (14 m) and a deck 52 ft wide.

Who owns Otis ST over Mill Creek?

It is owned by the City or Municipal Highway Agency.