US Bridges

Old County RD S over Brennan Brook

Fair

Hillsborough County, New Hampshire · Town RD · Structure no. 008601120007700

Built
1930
95 years old, rebuilt 1992
Condition
Fair
inspected October 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
23 ft
1 main span
Daily traffic
27
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Old County RD S over Brennan Brook is a steel stringer/multi-beam or girder carrying Old County RD S over Brennan Brook in Hillsborough County, New Hampshire. It was built in 1930 and reconstructed in 1992, so it is 95 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 27 vehicles a day, projected to reach 39 by 2043. The structure is 23 ft (7 m) long and 20 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesOld County RD S
CrossesBrennan Brook
LocationTown RD
CountyHillsborough County
StateNew Hampshire
Coordinates42.96927, -71.79917
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 inspectionOctober 2024
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 geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating37 US tons
Inventory rating28 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans1
Design loadUnknown
Structure length23 ft (7 m)
Longest span16 ft (4.9 m)
Deck width20 ft (6.1 m)
Roadway width16 ft (5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic27 (2023)
Projected traffic39 by 2043
Trucks0%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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 Old County RD S over Brennan Brook built?

It was built in 1930, making it 95 years old in 2025. It was reconstructed in 1992.

What condition is Old County RD S over Brennan 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 October 2024.

How much traffic does Old County RD S over Brennan Brook carry?

About 27 vehicles per day (2023 count).

How long is Old County RD S over Brennan Brook?

The structure is 23 ft (7 m) long with a longest span of 16 ft (4.9 m) and a deck 20 ft wide.

Who owns Old County RD S over Brennan Brook?

It is owned by the City or Municipal Highway Agency.