US Bridges

Mo 9 S over Missouri Rvr

FairPosted for load

Clay County, Missouri · S 26 T 50 N R 33 W · Structure no. 3335

Built
1987
38 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
3,318 ft
19 main spans
Daily traffic
19,160
2024 count
Owner
State
State Highway Agency

About this bridge

Mo 9 S over Missouri Rvr is a steel continuous stringer/multi-beam or girder carrying Mo 9 S over Missouri Rvr in Clay County, Missouri. It was built in 1987, so it is 38 years old, younger than the Missouri average of 45.1 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 19,160 vehicles a day, roughly 4% of them trucks, projected to reach 30,656 by 2044. The structure is 3,318 ft (1,011.3 m) long and 84 ft wide. If it were closed, the detour would be 11.8 mi (19 km).

Location

Open in Google Maps
CarriesMo 9 S
CrossesMissouri Rvr
LocationS 26 T 50 N R 33 W
RouteState Highway 9
CountyClay County
StateMissouri
Coordinates39.11648, -94.57877
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusPosted for load 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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55.6 US tons
Inventory rating33.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans19
Design loadHS 20 + Mod
Structure length3,318 ft (1,011.3 m)
Longest span440 ft (134.1 m)
Deck width84 ft (25.5 m)
Roadway width72 ft (21.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic19,160 (2024)
Projected traffic30,656 by 2044
Trucks4%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed11.8 mi (19 km)
TollOn a free road
National Highway SystemYes

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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was Mo 9 S over Missouri Rvr built?

It was built in 1987, making it 38 years old in 2025.

What condition is Mo 9 S over Missouri Rvr 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 Mo 9 S over Missouri Rvr carry?

About 19,160 vehicles per day (2024 count), of which roughly 4% are trucks.

How long is Mo 9 S over Missouri Rvr?

The structure is 3,318 ft (1,011.3 m) long with a longest span of 440 ft (134.1 m) and a deck 84 ft wide.

Who owns Mo 9 S over Missouri Rvr?

It is owned by the State Highway Agency.