US Bridges

Main Street over Mascoma River

Good

Grafton County, New Hampshire · .3 Mi. SW from Inv RTE 40 · Structure no. 007700790015300

Built
1954
71 years old, rebuilt 2004
Condition
Good
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
92 ft
2 main spans
Daily traffic
1,358
2023 count
Owner
State
State Highway Agency

About this bridge

Main Street over Mascoma River is a steel stringer/multi-beam or girder carrying Main Street over Mascoma River in Grafton County, New Hampshire. It was built in 1954 and reconstructed in 2004, so it is 71 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 1,358 vehicles a day, roughly 10% of them trucks, projected to reach 2,009 by 2043. The structure is 92 ft (28 m) long and 30 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesMain Street
CrossesMascoma River
Location.3 Mi. SW from Inv RTE 40
RouteState Highway 0
CountyGrafton County
StateNew Hampshire
Coordinates43.64068, -72.1488
Functional classUrban Collector

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.
Superstructure8 Very GoodNo problems noted.
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 evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating50.9 US tons
Inventory rating30.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadHS 15
Structure length92 ft (28 m)
Longest span44 ft (13.4 m)
Deck width30 ft (9.1 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,358 (2023)
Projected traffic2,009 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
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 Main Street over Mascoma River built?

It was built in 1954, making it 71 years old in 2025. It was reconstructed in 2004.

What condition is Main Street over Mascoma River 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 Main Street over Mascoma River carry?

About 1,358 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Main Street over Mascoma River?

The structure is 92 ft (28 m) long with a longest span of 44 ft (13.4 m) and a deck 30 ft wide.

Who owns Main Street over Mascoma River?

It is owned by the State Highway Agency.