Crescent City Connection Bridge No. 2
New Orleans, Louisiana

Client:

Louisiana Department of Transportation and Development
Construction Cost:

Fee
Completion Date:

1998

Project Information:

The Crescent City Connection Bridge No. 2 is a highway bridge which crosses the Mississippi River in New Orleans, Louisiana. It was completed in 1985 and is located 400 ft. downstream of the Crescent City Connection Bridge No. 1. The main bridge is a steel cantilever through truss supported on reinforced concrete piers with caisson type foundations. The center span is 1,575 ft. long and its vertical clearance is 150 ft. from high water level. A timber fender system connected to Pier II consists of cross layers of 12 x 12 timber, four piles thick. The navigation channel is 750 ft. wide and 45 ft. deep.

Modjeski & Masters, Inc. conducted an evaluation of the vulnerability of the bridge to vessel collision, and made recommendations to reduce the risk and consequences of vessel collisions. Several factors affecting the risk and consequences of vessel collisions were investigated including bridge characteristics, waterway characteristics, history of vessel collisions with the bridge and analysis of the accidents, vessel traffic characteristics and navigation conditions, and marine terminals, wharves and docks near the bridge and their impact on navigation. The risk analysis that considers all of these factors has been performed in accordance with Method II of the "AASHTO Guide Specification and Commentary for Vessel Collision Design of Highway Bridges."

To evaluate the vulnerability of the superstructure, a procedure consistent with the substructure risk analysis was developed. Probability distributions for the vessel size, draft and height, and for river stage were determined so that a more detailed probability based risk assessment could be made. In addition, an investigation of the effects of ship size, speed and loading condition, and water level on the governing failure modes has been conducted not only for assessing the risk and consequences of vessel collision, but also for developing an effective pier protection or strengthening scheme, if required.

 

 

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