Causeway Boulevard - 17th Street Canal, Route I-10, Jefferson Parish
Client: LaDOTD - Louisiana, Statewide
Completion Date: 12/2008
Scope of Services
Preliminary Plans, Final Plans, Specifications, and Estimate of Probable Construction Cost
Shop Drawing Review and Construction Support
GEC was the lead design engineering firm for another very high profile project, this one in Metairie, La. Our company now further assists the state highway department in construction supervision until its scheduled October, 2008 completion.
This $70 million project consists of the widening, including bridges, of a 2-mile segment of a major urban arterial from 6 lanes to 8 to 12 lanes. The complexity of the design resulted in a construction drawing plan set of almost 1,200 sheets.
The additional travel lanes are being added to both the median and outside edges of the existing roadway using an asphaltic concrete pavement section.
There are 6 on-and off-ramps within the project segments. All of them are being completely reconstructed to accommodate the changed geometry of the main roadway. In one instance, a new “flyover” on-ramp is being constructed to ensure the free flow of criss-crossing ramp traffic. Design of that includes a two-span, 400-foot long continuous-covered steel plate girder unit supported by an integral steel bent cap. AASHTO standards for all of the ramp acceleration and deceleration lanes were also designed into the complicated roadway geometrics.
Outside of the ramps on both sides of the main roadway are one-way frontage roads. These too, for the majority of the project length, are being relocated and reconstructed to accommodate the geometric needs. In spite of the average right-of-way width of 300 feet, the congested geometry dictated by the project needs, leaves very little “green space” following construction.
Within the project limits are two bridges in each direction totaling 0.62 miles in length. All four of these bridges are being widened on both the median and outside rails. Further, because of their age, the decks of the existing bridges are being hydro-blasted and replaced with a new paved concrete surface.
Pile-supported sound barriers over its entire length are yet another fundamental component of this highly complex project. Walls of 12- to 20-foot heights are being placed on the outside bridge rails and between the main roadway and frontage roads. The walls required a separate set of plan-profile drawings to define their locations, foundations, heights, and bottom profiles.
Drainage on nearly all of the project is accomplished by a sub-surface storm structure system. Hence, this was yet another major component of the design accomplished on this project. Almost 300 new drainage inlets, along with connecting piping, were designed to expand and modify the existing system.
In addition to the very tight geometric complexities managed by GEC, another major challenge was the development of the plan for the sequencing of construction. Three lanes of traffic in both directions must be maintained, and two of the 12 multi-stage construction phases require the shifting of all traffic to one side of the median. The plan required the design of numerous detours, along with associated temporary striping and signing.
In summary, its successful work on this large and complex project further established GEC as a leading source of engineering skill and expertise.
