Structure 701750009900 · Hillsborough County, NH

Nh101 over Merrimack Road

Carries Nh101 over Merrimack Road, 0.7 Mi Milford Tl.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructuresets the rating7/9 · Good
Substructuresets the rating7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT72 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

72 ft end to end. Lengths and the car on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built1969rebuilt 2011
Length71.9 ft21.9 m
Daily traffic15,196counted 2023
Last inspectedJune 2023every 24 months

Location

StateNew Hampshire
CountyHillsborough
Location0.7 Mi Milford Tl
CarriesNh101
CrossesMerrimack Road
Coordinates42.83660, -71.61900

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length71.9 ft (21.9 m)
Max Span67.9 ft (20.7 m)
Deck Width45.9 ft (14 m)
Deck Area306.6 sq m
Main Spans1
Year Built1969 (reconstructed 2011)

Traffic

Avg Daily Traffic15,196 (2023)
Truck Traffic7%
Lanes On Bridge2
Lanes Under Bridge2

Inspection & Ownership

Last InspectionJune 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is possibly eligible (requires evaluation)
Scour CriticalNot applicable
Structure Number000701750009900

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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