US Bridges

Nahm RD over Sehrt CR

Fair

St. Charles County, Missouri · S 10 T 44 N R 1 E · Structure no. 22701

Built
1900
125 years old, rebuilt 2007
Condition
Fair
inspected February 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
63 ft
2 main spans
Daily traffic
10
2024 count
Owner
County
County Highway Agency

About this bridge

Nahm RD over Sehrt CR is a steel stringer/multi-beam or girder carrying Nahm RD over Sehrt CR in St. Charles County, Missouri. It was built in 1900 and reconstructed in 2007, so it is 125 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 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 10 vehicles a day, roughly 5% of them trucks, projected to reach 22 by 2044. The structure is 63 ft (19.2 m) long and 17 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesNahm RD
CrossesSehrt CR
LocationS 10 T 44 N R 1 E
RouteCounty Highway 370
CountySt. Charles County
StateMissouri
Coordinates38.58694, -90.89661
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
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 protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating77.4 US tons
Inventory rating46.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length63 ft (19.2 m)
Longest span31 ft (9.4 m)
Deck width17 ft (5.1 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10 (2024)
Projected traffic22 by 2044
Trucks5%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Nahm RD over Sehrt CR built?

It was built in 1900, making it 125 years old in 2025. It was reconstructed in 2007.

What condition is Nahm RD over Sehrt CR 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 February 2024.

How much traffic does Nahm RD over Sehrt CR carry?

About 10 vehicles per day (2024 count), of which roughly 5% are trucks.

How long is Nahm RD over Sehrt CR?

The structure is 63 ft (19.2 m) long with a longest span of 31 ft (9.4 m) and a deck 17 ft wide.

Who owns Nahm RD over Sehrt CR?

It is owned by the County Highway Agency.