Tappen Zee Bridge

     Named for a local Tappan Indian Tribe and the Dutch word for a wide expanse of water, Tappan Zee creates one of the most unforgettable bridge names in America. Connecting Tarrytown to Nyack, the New York Thruway bridge crosses one of the widest points of the Hudson River. With its approaches and main cantilever span, the bridge is well over three miles long.
     Completed in 1955, one of the most unique features of the bridge is its main supports. Because the Hudson River bottom is mostly clay and silt, steel pipe pilings were driven down nearly 300 feet into the bedrock. These pilings were then used to pin huge concrete caissons in place. The most unique aspect of the system is this group of floating caissons which support 70 percent of the bridge's weight. Built at Grassy Point up-river, a site that was converted into the world's largest drydock, the hollow caissons were brought in by barge. The two largest, weighing 16,000 tons each, and are routinely pumped out to maintain their buoyancy.
     Still the ninth longest cantilever span in the world, the bridge carries about 135,000 vehicles a day. Built with a life span of only 50 years, plans are being studied for a replacement bridge. Located about 25 miles of mid-town Manhattan, the bridge is an important I-287 link and is naturally expected to carry more and more traffic. New bridge designs look to accommodate rail, bus and a standard roadway, but cost estimates have soared to 16 billion dollars. Hopes to incorporate a Bus Rapid Transit system and commuter train tracks into the plans further delay construction and add to concerns of an ageing Tappan Zee Bridge.

    Tappan Zee Bridge Map