US Bridges

Shem Valley Road over Brock Brook

Good

Grafton County, New Hampshire · 0.04 MI Knowles Hill RD · Structure no. 000300960011200

Built
1930
95 years old, rebuilt 2024
Condition
Good
inspected November 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
38 ft
1 main span
Daily traffic
96
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Shem Valley Road over Brock Brook is a steel stringer/multi-beam or girder carrying Shem Valley Road over Brock Brook in Grafton County, New Hampshire. It was built in 1930 and reconstructed in 2024, so it is 95 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 9 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 96 vehicles a day, roughly 4% of them trucks, projected to reach 142 by 2043. The structure is 38 ft (11.6 m) long and 20 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesShem Valley Road
CrossesBrock Brook
Location0.04 MI Knowles Hill RD
CountyGrafton County
StateNew Hampshire
Coordinates43.63877, -71.85643
Functional classRural Local

Condition and inspection

Good

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

ComponentRatingMeaning
Deck9 ExcellentNo problems noted.
Superstructure9 ExcellentNo problems noted.
Substructure9 ExcellentNo problems noted.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation9: Superior to present desirable criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating92 US tons
Inventory rating71 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans1
Design loadHL 93
Structure length38 ft (11.6 m)
Longest span36 ft (11 m)
Deck width20 ft (6.2 m)
Roadway width20 ft (6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic96 (2023)
Projected traffic142 by 2043
Trucks4%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 Shem Valley Road over Brock Brook built?

It was built in 1930, making it 95 years old in 2025. It was reconstructed in 2024.

What condition is Shem Valley Road over Brock Brook 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 2024.

How much traffic does Shem Valley Road over Brock Brook carry?

About 96 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Shem Valley Road over Brock Brook?

The structure is 38 ft (11.6 m) long with a longest span of 36 ft (11 m) and a deck 20 ft wide.

Who owns Shem Valley Road over Brock Brook?

It is owned by the City or Municipal Highway Agency.