US Bridges

Cohas Avenue over Cohas Brook

Good

Hillsborough County, New Hampshire · 0.8 MI S Island Pond RD · Structure no. 016101760013300

Built
1900
125 years old
Condition
Good
inspected July 2024
Type
Arch - Deck
Masonry
Length
47 ft
2 main spans
Daily traffic
2,560
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Cohas Avenue over Cohas Brook is a masonry arch - deck carrying Cohas Avenue over Cohas Brook in Hillsborough County, New Hampshire. It was built in 1900, so it is 125 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 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 2,560 vehicles a day, roughly 3% of them trucks, projected to reach 3,788 by 2043. The structure is 47 ft (14.3 m) long and 31 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesCohas Avenue
CrossesCohas Brook
Location0.8 MI S Island Pond RD
RouteCity Street 0
Coordinates42.96106, -71.40256
Functional classUrban Collector

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation7: Better than present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating63.1 US tons
Inventory rating63.1 US tons

Structure

Structure typeArch - Deck
MaterialMasonry
DeckConcrete, cast-in-place
Main spans2
Design loadUnknown
Structure length47 ft (14.3 m)
Longest span16 ft (4.9 m)
Deck width31 ft (9.4 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,560 (2023)
Projected traffic3,788 by 2043
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 Cohas Avenue over Cohas Brook built?

It was built in 1900, making it 125 years old in 2025.

What condition is Cohas Avenue over Cohas 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 July 2024.

How much traffic does Cohas Avenue over Cohas Brook carry?

About 2,560 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is Cohas Avenue over Cohas Brook?

The structure is 47 ft (14.3 m) long with a longest span of 16 ft (4.9 m) and a deck 31 ft wide.

Who owns Cohas Avenue over Cohas Brook?

It is owned by the City or Municipal Highway Agency.