US Bridges

Nh 28 S Willow ST over Cohas Brook

Fair

Hillsborough County, New Hampshire · 1.2 MI N Londonderry Tl · Structure no. 016101900010000

Built
1989
36 years old
Condition
Fair
inspected July 2024
Type
Culvert
Concrete
Length
37 ft
1 main span
Daily traffic
16,239
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Nh 28 S Willow ST over Cohas Brook is a concrete culvert carrying Nh 28 S Willow ST over Cohas Brook in Hillsborough County, New Hampshire. It was built in 1989, so it is 36 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 fair condition with a lowest component rating of 6 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 16,239 vehicles a day, roughly 5% of them trucks, projected to reach 24,033 by 2043. The structure is 37 ft (11.3 m) long. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesNh 28 S Willow ST
CrossesCohas Brook
Location1.2 MI N Londonderry Tl
RouteState Highway 28
CountyHillsborough County
StateNew Hampshire
Coordinates42.94703, -71.4333
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating82.1 US tons
Inventory rating49.1 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans1
Design loadHS 20 + Mod
Structure length37 ft (11.3 m)
Longest span32 ft (9.8 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,239 (2023)
Projected traffic24,033 by 2043
Trucks5%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes

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 Nh 28 S Willow ST over Cohas Brook built?

It was built in 1989, making it 36 years old in 2025.

What condition is Nh 28 S Willow ST over Cohas 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 July 2024.

How much traffic does Nh 28 S Willow ST over Cohas Brook carry?

About 16,239 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Nh 28 S Willow ST over Cohas Brook?

The structure is 37 ft (11.3 m) long with a longest span of 32 ft (9.8 m).

Who owns Nh 28 S Willow ST over Cohas Brook?

It is owned by the City or Municipal Highway Agency.