US Bridges

Twelth ST over I-495 RD 60

Fair

New Castle County, Delaware · Wilmington · Structure no. 1815 009

Built
1977
48 years old
Condition
Fair
inspected February 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
191 ft
2 main spans
Daily traffic
5,790
2022 count
Owner
State
State Highway Agency

About this bridge

Twelth ST over I-495 RD 60 is a steel continuous stringer/multi-beam or girder carrying Twelth ST over I-495 RD 60 in New Castle County, Delaware. It was built in 1977, so it is 48 years old, older than the Delaware average of 47.3 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 5,790 vehicles a day, roughly 7% of them trucks, projected to reach 8,198 by 2042. The structure is 191 ft (58.1 m) long and 80 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesTwelth ST
CrossesI-495 RD 60
LocationWilmington
RouteCounty Highway 9
CountyNew Castle County
StateDelaware
Coordinates39.73566, -75.52155
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 inspectionFebruary 2024
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 geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating92.2 US tons
Inventory rating71.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length191 ft (58.1 m)
Longest span92 ft (28 m)
Deck width80 ft (24.4 m)
Roadway width52 ft (15.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,790 (2022)
Projected traffic8,198 by 2042
Trucks7%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed3.1 mi (5 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 Twelth ST over I-495 RD 60 built?

It was built in 1977, making it 48 years old in 2025.

What condition is Twelth ST over I-495 RD 60 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 Twelth ST over I-495 RD 60 carry?

About 5,790 vehicles per day (2022 count), of which roughly 7% are trucks.

How long is Twelth ST over I-495 RD 60?

The structure is 191 ft (58.1 m) long with a longest span of 92 ft (28 m) and a deck 80 ft wide.

Who owns Twelth ST over I-495 RD 60?

It is owned by the State Highway Agency.