US Bridges

Mo 79 N over Or 70 NS RR

Fair

St. Charles County, Missouri · S 731 T 47 N R 3 E · Structure no. 3510

Built
1985
40 years old
Condition
Fair
inspected September 2023
Type
Tee Beam
Prestressed Concrete Continuous
Length
190 ft
4 main spans
Daily traffic
10,887
2024 count
Owner
State
State Highway Agency

About this bridge

Mo 79 N over Or 70 NS RR is a prestressed concrete continuous tee beam carrying Mo 79 N over Or 70 NS RR in St. Charles County, Missouri. It was built in 1985, so it is 40 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.

It carries about 10,887 vehicles a day, roughly 11% of them trucks, projected to reach 19,597 by 2044. The structure is 190 ft (57.9 m) long and 50 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesMo 79 N
CrossesOr 70 NS RR
LocationS 731 T 47 N R 3 E
RouteState Highway 79
CountySt. Charles County
StateMissouri
Coordinates38.80773, -90.64935
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
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
Approach roadway alignment8: Equal to present desirable criteria
Operating rating72.4 US tons
Inventory rating43.7 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length190 ft (57.9 m)
Longest span51 ft (15.4 m)
Deck width50 ft (15.1 m)
Roadway width47 ft (14.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,887 (2024)
Projected traffic19,597 by 2044
Trucks11%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and railroad
Detour if closed0.6 mi (1 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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Mo 79 N over Or 70 NS RR built?

It was built in 1985, making it 40 years old in 2025.

What condition is Mo 79 N over Or 70 NS RR 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 Mo 79 N over Or 70 NS RR carry?

About 10,887 vehicles per day (2024 count), of which roughly 11% are trucks.

How long is Mo 79 N over Or 70 NS RR?

The structure is 190 ft (57.9 m) long with a longest span of 51 ft (15.4 m) and a deck 50 ft wide.

Who owns Mo 79 N over Or 70 NS RR?

It is owned by the State Highway Agency.