US Bridges

I-93 NB over Tripoli Road

Fair

Grafton County, New Hampshire · 3.46 MI Lincoln Tl · Structure no. 028402010010800

Built
1972
53 years old, rebuilt 1986
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
148 ft
1 main span
Daily traffic
7,017
2023 count
Owner
State
State Highway Agency

About this bridge

I-93 NB over Tripoli Road is a steel stringer/multi-beam or girder carrying I-93 NB over Tripoli Road in Grafton County, New Hampshire. It was built in 1972 and reconstructed in 1986, so it is 53 years old, younger than the New Hampshire average of 56.9 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 7,017 vehicles a day, roughly 10% of them trucks, projected to reach 10,385 by 2043. The structure is 148 ft (45.1 m) long and 45 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-93 NB
CrossesTripoli Road
Location3.46 MI Lincoln Tl
RouteInterstate 93
CountyGrafton County
StateNew Hampshire
Coordinates43.98936, -71.67277
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating60.7 US tons
Inventory rating36.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length148 ft (45.1 m)
Longest span140 ft (42.7 m)
Deck width45 ft (13.7 m)
Roadway width40 ft (12.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,017 (2023)
Projected traffic10,385 by 2043
Trucks10%
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$314,000 (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-93 NB over Tripoli Road built?

It was built in 1972, making it 53 years old in 2025. It was reconstructed in 1986.

What condition is I-93 NB over Tripoli 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 April 2023.

How much traffic does I-93 NB over Tripoli Road carry?

About 7,017 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is I-93 NB over Tripoli Road?

The structure is 148 ft (45.1 m) long with a longest span of 140 ft (42.7 m) and a deck 45 ft wide.

Who owns I-93 NB over Tripoli Road?

It is owned by the State Highway Agency.