US Bridges

Center Road over Mill Brook

Fair

Sullivan County, New Hampshire · 3.5 MI N of NH12A · Structure no. 005501070011800

Built
1950
75 years old, rebuilt 1975
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
24 ft
1 main span
Daily traffic
149
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Center Road over Mill Brook is a steel stringer/multi-beam or girder carrying Center Road over Mill Brook in Sullivan County, New Hampshire. It was built in 1950 and reconstructed in 1975, so it is 75 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 fair condition with a lowest component rating of 5 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 149 vehicles a day, roughly 4% of them trucks, projected to reach 220 by 2043. The structure is 24 ft (7.3 m) long and 20 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesCenter Road
CrossesMill Brook
Location3.5 MI N of NH12A
CountySullivan County
StateNew Hampshire
Coordinates43.48091, -72.34178
Functional classRural Local

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating25.2 US tons
Inventory rating18 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckCorrugated steel
Main spans1
Design loadUnknown
Structure length24 ft (7.3 m)
Longest span20 ft (6.1 m)
Deck width20 ft (6.1 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic149 (2023)
Projected traffic220 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 Center Road over Mill Brook built?

It was built in 1950, making it 75 years old in 2025. It was reconstructed in 1975.

What condition is Center Road over Mill Brook 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 September 2023.

How much traffic does Center Road over Mill Brook carry?

About 149 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Center Road over Mill Brook?

The structure is 24 ft (7.3 m) long with a longest span of 20 ft (6.1 m) and a deck 20 ft wide.

Who owns Center Road over Mill Brook?

It is owned by the City or Municipal Highway Agency.