US Bridges

Mo 51 S over Kaskaskia ST Mississi

PoorPosted for load

Perry County, Missouri · S 1007 T 37 N R 11 E · Structure no. 6656

Built
1942
83 years old
Condition
Poor
inspected February 2024
Type
Truss - Thru
Steel Continuous
Length
2,827 ft
2 main spans
Daily traffic
3,806
2024 count
Owner
State
State Highway Agency

About this bridge

Mo 51 S over Kaskaskia ST Mississi is a steel continuous truss - thru carrying Mo 51 S over Kaskaskia ST Mississi in Perry County, Missouri. It was built in 1942, so it is 83 years old, older than the Missouri average of 45.1 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for load restriction.

It carries about 3,806 vehicles a day, roughly 24% of them trucks, projected to reach 7,231 by 2044. The structure is 2,827 ft (861.7 m) long and 23 ft wide. If it were closed, the detour would be 88.2 mi (142 km).

Location

Open in Google Maps
CarriesMo 51 S
CrossesKaskaskia ST Mississi
LocationS 1007 T 37 N R 11 E
RouteState Highway 51
CountyPerry County
StateMissouri
Coordinates37.90076, -89.83878
Functional classRural Principal Arterial - Other

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating46.6 US tons
Inventory rating27.8 US tons

Structure

Structure typeTruss - Thru
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2 (+12 approach)
Design loadOther
Structure length2,827 ft (861.7 m)
Longest span670 ft (204.2 m)
Deck width23 ft (6.9 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deck20 ft (6 m)

Traffic and service

Average daily traffic3,806 (2024)
Projected traffic7,231 by 2044
Trucks24%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway, waterway and railroad
Detour if closed88.2 mi (142 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$99 million (2025 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was Mo 51 S over Kaskaskia ST Mississi built?

It was built in 1942, making it 83 years old in 2025.

What condition is Mo 51 S over Kaskaskia ST Mississi in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in February 2024.

How much traffic does Mo 51 S over Kaskaskia ST Mississi carry?

About 3,806 vehicles per day (2024 count), of which roughly 24% are trucks.

How long is Mo 51 S over Kaskaskia ST Mississi?

The structure is 2,827 ft (861.7 m) long with a longest span of 670 ft (204.2 m) and a deck 23 ft wide.

Who owns Mo 51 S over Kaskaskia ST Mississi?

It is owned by the State Highway Agency.