As part of Tappan Zee Constructors’ (TZC) efforts to progress the eastbound bridge while maintaining traffic on the existing bridge, piles needed to be driven under portions of the existing bridge and concrete pours performed for Piers 2EB, 3EB and 4EB. In less than 6 months, County Fabricators completed the fabrication of three (3)-155 ton cofferdams with overall lengths between 70’ to 80’ and widths of 35’, which served as the form work for the new piers. Each cofferdam housed between 11 to 15 pile sleeves of 48” diameter and over 20’ heights. The custom fabrication included water-tight, removable steel walls and removable upper pile sleeves. Fabrication also included built-up nose walers with rolled radii of 14’ and 16’, lifting trunnions, and gate valve assemblies. These massive steel “bathtubs” were fabricated and assembled at County Fabricators’ bulkhead to allow TZC access to easily pick up and float each cofferdam down the Hudson River directly to the job site. As part of a change order, County Fabricator also completed the floating cofferdam for Pier 40EB within 2 months. This 185-ton cofferdam was similar in design to the first 3, but housed 24 pile sleeves of 48” diameter at approximately 21’ high in its 72’ x 39’ steel body.