US Bridges

County RD 520 over Grass Waterway

FairPosted for load

Shelby County, Missouri · S 28 T 56 N R 12 W · Structure no. 22912

Built
1978
47 years old
Condition
Fair
inspected March 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
26 ft
1 main span
Daily traffic
30
2024 count
Owner
County
County Highway Agency

About this bridge

County RD 520 over Grass Waterway is a steel stringer/multi-beam or girder carrying County RD 520 over Grass Waterway in Shelby County, Missouri. It was built in 1978, so it is 47 years old, older 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 6 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 30 vehicles a day, roughly 10% of them trucks, projected to reach 38 by 2044. The structure is 26 ft (7.9 m) long and 16 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

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CarriesCounty RD 520
CrossesGrass Waterway
LocationS 28 T 56 N R 12 W
RouteCounty Highway 380
CountyShelby County
StateMissouri
Coordinates39.61958, -92.25092
Functional classRural 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating15.9 US tons
Inventory rating9.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadOther
Structure length26 ft (7.9 m)
Longest span24 ft (7.3 m)
Deck width16 ft (4.9 m)
Roadway width16 ft (4.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30 (2024)
Projected traffic38 by 2044
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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$255,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was County RD 520 over Grass Waterway built?

It was built in 1978, making it 47 years old in 2025.

What condition is County RD 520 over Grass Waterway 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 March 2024.

How much traffic does County RD 520 over Grass Waterway carry?

About 30 vehicles per day (2024 count), of which roughly 10% are trucks.

How long is County RD 520 over Grass Waterway?

The structure is 26 ft (7.9 m) long with a longest span of 24 ft (7.3 m) and a deck 16 ft wide.

Who owns County RD 520 over Grass Waterway?

It is owned by the County Highway Agency.