US Bridges

Patterson Hill RD over Contoocook River

Fair

Merrimack County, New Hampshire · 3.6 MI FR Deering Tl · Structure no. 012000970010100

Built
1915
110 years old, rebuilt 2001
Condition
Fair
inspected October 2023
Type
Truss - Thru
Steel
Length
119 ft
1 main span
Daily traffic
147
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Patterson Hill RD over Contoocook River is a steel truss - thru carrying Patterson Hill RD over Contoocook River in Merrimack County, New Hampshire. It was built in 1915 and reconstructed in 2001, so it is 110 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 147 vehicles a day, roughly 4% of them trucks, projected to reach 217 by 2043. The structure is 119 ft (36.3 m) long and 14 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesPatterson Hill RD
CrossesContoocook River
Location3.6 MI FR Deering Tl
CountyMerrimack County
StateNew Hampshire
Coordinates43.16801, -71.84159
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
Deck9 ExcellentNo problems noted.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionOctober 2023
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 geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment4: Meets minimum tolerable limits to be left in place as is
Operating rating37.1 US tons
Inventory rating22.3 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckWood or timber
Main spans1
Design loadH 20
Structure length119 ft (36.3 m)
Longest span113 ft (34.4 m)
Deck width14 ft (4.4 m)
Roadway width13 ft (4.1 m)
Vertical clearance over deck13 ft (4.1 m)

Traffic and service

Average daily traffic147 (2023)
Projected traffic217 by 2043
Trucks4%
Lanes on structure1
Traffic directionOne-lane bridge for two-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 statusEligible 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 Patterson Hill RD over Contoocook River built?

It was built in 1915, making it 110 years old in 2025. It was reconstructed in 2001.

What condition is Patterson Hill RD over Contoocook River 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 2023.

How much traffic does Patterson Hill RD over Contoocook River carry?

About 147 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Patterson Hill RD over Contoocook River?

The structure is 119 ft (36.3 m) long with a longest span of 113 ft (34.4 m) and a deck 14 ft wide.

Who owns Patterson Hill RD over Contoocook River?

It is owned by the City or Municipal Highway Agency.