US Bridges

NH145 over Bishop Brook

Good

Coos County, New Hampshire · 2.8 MI N of Colbrook Tl · Structure no. 024101220011500

Built
2017
8 years old
Condition
Good
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
55 ft
1 main span
Daily traffic
602
2023 count
Owner
State
State Highway Agency

About this bridge

NH145 over Bishop Brook is a steel stringer/multi-beam or girder carrying NH145 over Bishop Brook in Coos County, New Hampshire. It was built in 2017, so it is 8 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 602 vehicles a day, roughly 10% of them trucks, projected to reach 890 by 2043. The structure is 55 ft (16.8 m) long and 31 ft wide. If it were closed, the detour would be 14.3 mi (23 km).

Location

Open in Google Maps
CarriesNH145
CrossesBishop Brook
Location2.8 MI N of Colbrook Tl
RouteState Highway 145
CountyCoos County
StateNew Hampshire
Coordinates44.9706, -71.44173
Functional classRural Major Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating78.7 US tons
Inventory rating60.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHL 93
Structure length55 ft (16.8 m)
Longest span50 ft (15.2 m)
Deck width31 ft (9.4 m)
Roadway width27 ft (8.2 m)
Vertical clearance over deck100 ft (30.5 m)

Traffic and service

Average daily traffic602 (2023)
Projected traffic890 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.3 mi (23 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 NH145 over Bishop Brook built?

It was built in 2017, making it 8 years old in 2025.

What condition is NH145 over Bishop 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 August 2023.

How much traffic does NH145 over Bishop Brook carry?

About 602 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is NH145 over Bishop Brook?

The structure is 55 ft (16.8 m) long with a longest span of 50 ft (15.2 m) and a deck 31 ft wide.

Who owns NH145 over Bishop Brook?

It is owned by the State Highway Agency.