US Bridges

Nh 3A Brown Ave over Cohas Brook

Fair

Hillsborough County, New Hampshire · 1.2 MI S of JCT I-193 · Structure no. 016102100007800

Built
1986
39 years old
Condition
Fair
inspected July 2024
Type
Slab
Prestressed Concrete
Length
35 ft
1 main span
Daily traffic
16,980
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Nh 3A Brown Ave over Cohas Brook is a prestressed concrete slab carrying Nh 3A Brown Ave over Cohas Brook in Hillsborough 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 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 16,980 vehicles a day, roughly 5% of them trucks, projected to reach 25,130 by 2043. The structure is 35 ft (10.7 m) long and 68 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesNh 3A Brown Ave
CrossesCohas Brook
Location1.2 MI S of JCT I-193
RouteState Highway 3A
CountyHillsborough County
StateNew Hampshire
Coordinates42.93159, -71.4521
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
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
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating59.2 US tons
Inventory rating46.4 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length35 ft (10.7 m)
Longest span32 ft (9.8 m)
Deck width68 ft (20.7 m)
Roadway width50 ft (15.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,980 (2023)
Projected traffic25,130 by 2043
Trucks5%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
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 3A Brown Ave over Cohas Brook built?

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

What condition is Nh 3A Brown Ave 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 3A Brown Ave over Cohas Brook carry?

About 16,980 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Nh 3A Brown Ave over Cohas Brook?

The structure is 35 ft (10.7 m) long with a longest span of 32 ft (9.8 m) and a deck 68 ft wide.

Who owns Nh 3A Brown Ave over Cohas Brook?

It is owned by the City or Municipal Highway Agency.