US Bridges

Irish Hill Rd. over Thorndyk Ditch

Good

Kent County, Delaware · S.W. of Magnolia · Structure no. 2031A031

Built
2019
6 years old
Condition
Good
inspected November 2021
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
60 ft
1 main span
Daily traffic
2,191
2020 count
Owner
State
State Highway Agency

About this bridge

Irish Hill Rd. over Thorndyk Ditch is a prestressed concrete box beam or girders - multiple carrying Irish Hill Rd. over Thorndyk Ditch in Kent County, Delaware. It was built in 2019, so it is 6 years old, younger than the Delaware average of 47.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 2,191 vehicles a day, roughly 7% of them trucks, projected to reach 2,723 by 2042. The structure is 60 ft (18.3 m) long and 40 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

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CarriesIrish Hill Rd.
CrossesThorndyk Ditch
LocationS.W. of Magnolia
RouteCounty Highway 31
CountyKent County
StateDelaware
Coordinates39.05508, -75.49445
Functional classRural Minor Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionNovember 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55.7 US tons
Inventory rating44 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHL 93
Structure length60 ft (18.3 m)
Longest span57 ft (17.4 m)
Deck width40 ft (12.3 m)
Roadway width38 ft (11.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,191 (2020)
Projected traffic2,723 by 2042
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed0.6 mi (1 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$300,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Irish Hill Rd. over Thorndyk Ditch built?

It was built in 2019, making it 6 years old in 2025.

What condition is Irish Hill Rd. over Thorndyk Ditch in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in November 2021.

How much traffic does Irish Hill Rd. over Thorndyk Ditch carry?

About 2,191 vehicles per day (2020 count), of which roughly 7% are trucks.

How long is Irish Hill Rd. over Thorndyk Ditch?

The structure is 60 ft (18.3 m) long with a longest span of 57 ft (17.4 m) and a deck 40 ft wide.

Who owns Irish Hill Rd. over Thorndyk Ditch?

It is owned by the State Highway Agency.