The New York Bridge Project is creating a state-of-the-art, twin-span replacement for the 3.1-mile Tappan Zee Bridge across the Hudson River
By Genevieve Smith
Photography by New York State Thruway Authority
After decades of delay, the state of New York is bringing to life the Tappan Zee Bridge project across the Hudson River between Westchester and Rockland counties.
Since construction operations began in late 2013, the New NY Bridge project has shown remarkable progress. Most of the substructure work—which includes piles and pier columns—is now complete. Construction continues with the ever-growing placement of steel-blue girders, road deck panels and segments of the iconic 419-foot main span towers.
The existing Governor Malcolm Wilson Tappan Zee Bridge opened to traffic in 1955 and is a vital artery for residents, commuters, travelers and commercial traffic. Bridge traffic has grown to about 138,000 vehicles per day, far more than the Tappan Zee was designed to support. The cost of maintaining the current bridge rivals the cost of a new bridge, with no improvements to current traffic conditions.
The New NY Bridge will provide less congestion for motorists, with eight general traffic lanes, breakdown/emergency lanes and a state-of-the-art traffic monitoring system. The new crossing will also be mass-transit ready, with space for Bus Rapid Transit as well as a design that can accommodate future light rail or commuter rail. The bridge will also feature a shared-use path for pedestrians and cyclists
Costing approximately $3.98 billion, the twin-span New NY Bridge is being designed and built to last more than a century without major structural repairs. The bridge is designed and being built by Tappan Zee Constructors, LLC (TZC), a group of some of the world’s best-known and most highly-regarded design, engineering and construction firms, including Fluor, American Bridge, Granite, and Traylor Bros., along with key design firms HDR, Buckland & Taylor, URS, and GZA. TZC is working closely on the project with a team of employees from the New York State Thruway Authority and the State Department of Transportation.
Following the successful completion of its phase one girder operations, the project’s largest crane has returned to familiar territory to help crews with road deck installation.
I Lift NY is currently installing the foundation of the driving surface on one of the most hard-to-reach areas on the new twin-span bridge. Utilizing the crane’s 328-foot lifting arm, Tappan Zee Constructors (TZC) will place 120 road deck panels in the area. The last time the super crane was in this area—June 2015—it set the bridge’s first steel girder assembly into place.
Designers developed the new bridge’s foundation based on a series of geotechnical investigations and laboratory testing. These studies included more than 150 soil borings and probes, some up to 440 feet beneath the riverbed. After analyzing the project’s subsurface conditions, engineers selected a foundation system featuring steel pipe piles up to six feet in diameter, to support the New NY Bridge. The weight of the new bridge is distributed down to these pile caps, which act as platforms for the bridge’s piers and towers.