Structure 800500009300 · Merrimack County, NH

Nh 11 over Blackwater River

Carries Nh 11 over Blackwater River, 0.7 Mi From Wilmot T.l..

Overall conditionGood

Set by its lowest-rated component: Deck and Substructure at 8 of 9.

How ratings work
Decksets the rating8/9 · Very Good
Superstructure9/9 · Excellent
Substructuresets the rating8/9 · Very Good
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT124 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9 · sets the ratingSuperstructure 9/9Substructure 8/9 · sets the rating

124 ft end to end, longest span 60 ft. Lengths and the semi-truck 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.

Built1959rebuilt 2013
Length124.0 ft37.8 m
Daily traffic5,615counted 2023
Last inspectedMay 2024every 24 months

Location

StateNew Hampshire
CountyMerrimack
Location0.7 Mi From Wilmot T.l.
CarriesNh 11
CrossesBlackwater River
Coordinates43.43117, -71.86867

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length124.0 ft (37.8 m)
Max Span60.0 ft (18.3 m)
Deck Width48.6 ft (14.8 m)
Deck Area559.4 sq m
Main Spans2
Year Built1959 (reconstructed 2013)

Traffic

Avg Daily Traffic5,615 (2023)
Truck Traffic7%
Lanes On Bridge2

Inspection & Ownership

Last InspectionMay 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is possibly eligible (requires evaluation)
Scour Critical7 — Countermeasures installed
Structure Number000800500009300

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.

Nearby Bridges