Envisioning the Future The BQE Triple Cantilever Project

2. Project Details

2.1. Project Overview

In 1940, urban planner Robert Moses recommended construction of the BQE in order to fill a gap in New York City's arterial system and aid in National defense, and work on the BQE was begun. Now almost 60 years old, this major artery is in need of reconstruction, with work being done in phases to accommodate burgeoning traffic.

The most notable bridge along the project corridor, the triple cantilever, is a reinforced concrete, multi-level structure built in 1948. It carries six lanes of the BQE on two cantilevers, with the three eastbound lanes located above the three westbound lanes. The third cantilever features the Brooklyn Heights Promenade, a pedestrian walkway with views of the East River and the Manhattan skyline. Furman Street runs parallel to the Interstate, at grade. Local street intersections and connections to the Brooklyn Bridge north of the triple cantilever add to the complexity of the structure.

NYSDOT has defined the scope of the BQE "triple cantilever" project as follows: 1) either rehabilitate or replace the triple cantilever itself, and 2) either rehabilitate or replace the 21 other structures within the project area. NYSDOT's primary goal is to address the safety and congestion problems caused by heavy traffic conditions throughout the corridor. The number of structures involved makes this a complex project, and traffic control will be a major challenge.

Table 1: Bridge Details

Note: A large percentage of the deck area noted above is carried on cantilever or other non-redundant structures, which complicates maintenance and protection of traffic (MPT) and staged construction procedures.

2.2. Project History and Development

NYSDOT plans to begin the EIS process in 2007, with a ROD expected in approximately five years.

As the project stands, several key decisions remain:

• NYSDOT must evaluate the effect of construction on through and local traffic patterns.
• The State needs to design around the "choke points."
• NYSDOT must implement operational improvements.
• The State needs to determine whether the corridor can be closed using either short-term closures or 24/7 construction operation.
• The DOT must evaluate the feasibility of using Furman Street as a detour and make a determination on temporary closure of the Brooklyn Bridge, the Manhattan Bridge and local street systems.
• NYSDOT needs to address substandard features and determine whether the alignment can be modified to improve these aspects.
• The State must determine whether shoulders can be added along a majority of the project corridor (if not everywhere).
• The DOT needs to evaluate whether opportunities to widen the triple cantilever promenade are feasible.
• NYSDOT must make a decision on CSS (at Parklands) and work to achieve public consensus.

2.3. Project Challenges

Traffic

This segment of I-278 carries a daily traffic volume of 123,000 vehicles and serves as a critical link for the metropolitan area. Connections to the Brooklyn Bridge, the Manhattan Bridge and the local street system fall within the project limits. Because this section of the highway carries both commuter and through traffic, the through traffic lanes must be maintained throughout the life of the project. NYSDOT must determine the most efficient means for this to be accomplished. In addition, the traffic impacts due to partial or complete closure must be addressed: NYSDOT must decide whether a short-term major construction project with total closure would be better than a long-term project with recurring nighttime closures.

Time

One of NYSDOT's goals is to minimize the amount of time that roadway traffic patterns will be affected. The project team has discussed the possibility of prefabricating structure components off-site, when possible, and bringing them in via barge on the East River.