US Bridges

Sullivan Drive over Mill Brook

Good

Grafton County, New Hampshire · 0.19 MI FR Millbrook RD · Structure no. 025401750014100

Built
1986
39 years old
Condition
Good
inspected May 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
45 ft
1 main span
Daily traffic
96
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Sullivan Drive over Mill Brook is a steel stringer/multi-beam or girder carrying Sullivan Drive over Mill Brook in Grafton County, New Hampshire. It was built in 1986, so it is 39 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 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 96 vehicles a day, roughly 4% of them trucks, projected to reach 142 by 2043. The structure is 45 ft (13.7 m) long and 27 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesSullivan Drive
CrossesMill Brook
Location0.19 MI FR Millbrook RD
CountyGrafton County
StateNew Hampshire
Coordinates43.92569, -71.61932
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
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating61.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length45 ft (13.7 m)
Longest span40 ft (12.2 m)
Deck width27 ft (8.2 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic96 (2023)
Projected traffic142 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-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 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 Sullivan Drive over Mill Brook built?

It was built in 1986, making it 39 years old in 2025.

What condition is Sullivan Drive over Mill 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 May 2024.

How much traffic does Sullivan Drive over Mill Brook carry?

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

How long is Sullivan Drive over Mill Brook?

The structure is 45 ft (13.7 m) long with a longest span of 40 ft (12.2 m) and a deck 27 ft wide.

Who owns Sullivan Drive over Mill Brook?

It is owned by the City or Municipal Highway Agency.