Structure 16101070007200 · Hillsborough County, NH

Salmon Street EB over Merrimack R Csx RD Ramp

Carries Salmon Street EB over Merrimack R Csx RD Ramp, 0.3mi W Of Jct RT 3.

Overall conditionPoor

Set by its lowest-rated component: Deck at 4 of 9.

How ratings work
Decksets the rating4/9 · Poor
Superstructure5/9 · Fair
Substructure5/9 · Fair
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT1,023 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 4/9 · sets the ratingSuperstructure 5/9Substructure 5/9

1,023 ft end to end, longest span 169 ft: about 2.8 football fields. 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.

Built1970rebuilt 1999
Length1023.0 ft311.8 m
Daily traffic13,150counted 2023
Last inspectedNovember 2024every 16 months

Location

StateNew Hampshire
CountyHillsborough
Location0.3mi W Of Jct RT 3
CarriesSalmon Street EB
CrossesMerrimack R Csx RD Ramp
Coordinates43.00358, -71.46972

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length1023.0 ft (311.8 m)
Max Span169.0 ft (51.5 m)
Deck Width33.8 ft (10.3 m)
Deck Area3211.5 sq m
Main Spans4
Year Built1970 (reconstructed 1999)

Traffic

Avg Daily Traffic13,150 (2023)
Truck Traffic5%
Lanes On Bridge2
Lanes Under Bridge3

Inspection & Ownership

Last InspectionNovember 2024
Inspection FrequencyEvery 16 months
OwnerCity/Municipal Highway Agency
Historical SignificanceBridge is possibly eligible (requires evaluation)
Scour Critical8 — Stable, low risk
Structure Number016101070007200

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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