US Bridges

Mason Knoll DR over Br of Grand Glaize

FairPosted for load

St. Louis County, Missouri · S 20 T 45 N R 5 E · Structure no. 23691

Built
1979
46 years old
Condition
Fair
inspected December 2023
Type
Culvert
Concrete Continuous
Length
27 ft
2 main spans
Daily traffic
40
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Mason Knoll DR over Br of Grand Glaize is a concrete continuous culvert carrying Mason Knoll DR over Br of Grand Glaize in St. Louis County, Missouri. It was built in 1979, so it is 46 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 40 vehicles a day, roughly 5% of them trucks, projected to reach 54 by 2043. The structure is 27 ft (8.2 m) long. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesMason Knoll DR
CrossesBr of Grand Glaize
LocationS 20 T 45 N R 5 E
RouteCity Street 0
CountySt. Louis County
StateMissouri
Coordinates38.6121, -90.47608
Functional classUrban 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
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating38.7 US tons
Inventory rating24.8 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadHS 20
Structure length27 ft (8.2 m)
Longest span12 ft (3.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic40 (2023)
Projected traffic54 by 2043
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Mason Knoll DR over Br of Grand Glaize built?

It was built in 1979, making it 46 years old in 2025.

What condition is Mason Knoll DR over Br of Grand Glaize 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 December 2023.

How much traffic does Mason Knoll DR over Br of Grand Glaize carry?

About 40 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Mason Knoll DR over Br of Grand Glaize?

The structure is 27 ft (8.2 m) long with a longest span of 12 ft (3.7 m).

Who owns Mason Knoll DR over Br of Grand Glaize?

It is owned by the City or Municipal Highway Agency.