US Bridges

I-89 Nh 10 NB over Riverside DR Mascoma Riv

Good

Grafton County, New Hampshire · 2.0 Mifrom Enfield T.L. · Structure no. 014401600011200

Built
1966
59 years old, rebuilt 1987
Condition
Good
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
306 ft
4 main spans
Daily traffic
16,261
2023 count
Owner
State
State Highway Agency

About this bridge

I-89 Nh 10 NB over Riverside DR Mascoma Riv is a steel stringer/multi-beam or girder carrying I-89 Nh 10 NB over Riverside DR Mascoma Riv in Grafton County, New Hampshire. It was built in 1966 and reconstructed in 1987, so it is 59 years old, older than the New Hampshire average of 56.9 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 16,261 vehicles a day, roughly 9% of them trucks, projected to reach 24,066 by 2043. The structure is 306 ft (93.3 m) long and 67 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesI-89 Nh 10 NB
CrossesRiverside DR Mascoma Riv
Location2.0 Mifrom Enfield T.L.
RouteInterstate 89
Coordinates43.63675, -72.2125
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Good

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating54 US tons
Inventory rating32 US tons

Structure

MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length306 ft (93.3 m)
Longest span80 ft (24.4 m)
Deck width67 ft (20.4 m)
Roadway width54 ft (16.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,261 (2023)
Projected traffic24,066 by 2043
Trucks9%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and waterway
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)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-89 Nh 10 NB over Riverside DR Mascoma Riv built?

It was built in 1966, making it 59 years old in 2025. It was reconstructed in 1987.

What condition is I-89 Nh 10 NB over Riverside DR Mascoma Riv 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 May 2023.

How much traffic does I-89 Nh 10 NB over Riverside DR Mascoma Riv carry?

About 16,261 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is I-89 Nh 10 NB over Riverside DR Mascoma Riv?

The structure is 306 ft (93.3 m) long with a longest span of 80 ft (24.4 m) and a deck 67 ft wide.

Who owns I-89 Nh 10 NB over Riverside DR Mascoma Riv?

It is owned by the State Highway Agency.