US Bridges

Is 83 Sbr over Thornton Mill Road

Fair

Baltimore County, Maryland · 0.9 M S of Br No 0305500 · Structure no. 100000030056012

Built
1959
66 years old, rebuilt 1989
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
112 ft
3 main spans
Daily traffic
60,263
2009 count
Owner
State
State Highway Agency

About this bridge

Is 83 Sbr over Thornton Mill Road is a steel stringer/multi-beam or girder carrying Is 83 Sbr over Thornton Mill Road in Baltimore County, Maryland. It was built in 1959 and reconstructed in 1989, so it is 66 years old, older than the Maryland average of 52.6 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.

It carries about 60,263 vehicles a day, roughly 8% of them trucks, projected to reach 36,050 by 2026. The structure is 112 ft (34.1 m) long and 47 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

No coordinates are recorded for this structure.

CarriesIs 83 Sbr
CrossesThornton Mill Road
Location0.9 M S of Br No 0305500
RouteInterstate 83
Functional classRural Principal Arterial - Interstate

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating77.5 US tons
Inventory rating46.5 US tons

Structure

MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length112 ft (34.1 m)
Longest span42 ft (12.8 m)
Deck width47 ft (14.2 m)
Roadway width44 ft (13.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic60,263 (2009)
Projected traffic36,050 by 2026
Trucks8%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 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 proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Is 83 Sbr over Thornton Mill Road built?

It was built in 1959, making it 66 years old in 2025. It was reconstructed in 1989.

What condition is Is 83 Sbr over Thornton Mill Road 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 June 2023.

How much traffic does Is 83 Sbr over Thornton Mill Road carry?

About 60,263 vehicles per day (2009 count), of which roughly 8% are trucks.

How long is Is 83 Sbr over Thornton Mill Road?

The structure is 112 ft (34.1 m) long with a longest span of 42 ft (12.8 m) and a deck 47 ft wide.

Who owns Is 83 Sbr over Thornton Mill Road?

It is owned by the State Highway Agency.