Structure 625230123900732 · St. Tammany County, LA

Cswy Bridge N. B. over Lake Pontchartrain

Carries Cswy Bridge N. B. over Lake Pontchartrain, Causeway - North Bound.

Overall conditionFair

Set by its lowest-rated component: Substructure at 5 of 9.

How ratings work
Deck7/9 · Good
Superstructure6/9 · Satisfactory
Substructuresets the rating5/9 · Fair
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
127,269 FT OVERALL5 MILES0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9Substructure 5/9 · sets the rating

127,269 ft end to end: about 354 football fields, or 24.1 miles. Lengths are drawn to scale; at this length a semi-truck would be a speck. 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 bascule bridge (drawn closed).

Built1965rebuilt 1969
Length127269.0 ft38791.6 m
Daily traffic18,830counted 1987
Last inspectedOctober 2024every 24 months

Location

StateLouisiana
CountySt. Tammany
LocationCauseway - North Bound
CarriesCswy Bridge N. B.
CrossesLake Pontchartrain
Coordinates30.01832, -90.15446

Physical Characteristics

MaterialSteel
DesignMovable - Bascule
Total Length127269.0 ft (38791.6 m)
Max Span180.1 ft (54.9 m)
Deck Width31.5 ft (9.6 m)
Deck Area372399.4 sq m
Main Spans1
Year Built1965 (reconstructed 1969)

Traffic

Avg Daily Traffic18,830 (1987)
Lanes On Bridge2

Inspection & Ownership

Last InspectionOctober 2024
Inspection FrequencyEvery 24 months
OwnerLocal Toll Authority
Historical SignificanceBridge is eligible for the National Register
Scour CriticalUnknown
Structure Number625230123900732

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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