US Bridges

Is 270 E over Cst Conway RD

Poor

St. Louis County, Missouri · S 15 T 45 N R 5 E · Structure no. 850

Built
1964
61 years old, rebuilt 1984
Condition
Poor
inspected October 2024
Type
Slab
Concrete Continuous
Length
179 ft
3 main spans
Daily traffic
182,944
2024 count
Owner
State
State Highway Agency

About this bridge

Is 270 E over Cst Conway RD is a concrete continuous slab carrying Is 270 E over Cst Conway RD in St. Louis County, Missouri. It was built in 1964 and reconstructed in 1984, so it is 61 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.

It carries about 182,944 vehicles a day, roughly 12% of them trucks, projected to reach 228,680 by 2044. The structure is 179 ft (54.6 m) long and 170 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesIs 270 E
CrossesCst Conway RD
LocationS 15 T 45 N R 5 E
RouteInterstate 270
CountySt. Louis County
StateMissouri
Coordinates38.64343, -90.44916
Functional classUrban Principal Arterial - Interstate

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.5 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length179 ft (54.6 m)
Longest span68 ft (20.7 m)
Deck width170 ft (51.7 m)
Roadway width165 ft (50.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic182,944 (2024)
Projected traffic228,680 by 2044
Trucks12%
Lanes on structure12
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed0.6 mi (1 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$5.4 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was Is 270 E over Cst Conway RD built?

It was built in 1964, making it 61 years old in 2025. It was reconstructed in 1984.

What condition is Is 270 E over Cst Conway RD 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 October 2024.

How much traffic does Is 270 E over Cst Conway RD carry?

About 182,944 vehicles per day (2024 count), of which roughly 12% are trucks.

How long is Is 270 E over Cst Conway RD?

The structure is 179 ft (54.6 m) long with a longest span of 68 ft (20.7 m) and a deck 170 ft wide.

Who owns Is 270 E over Cst Conway RD?

It is owned by the State Highway Agency.