Electric Boat Graving Docks 1 and 2 Construction Challenges

In 2004, Electric Boat initiated a long-term life extension project for Graving Docks 1 and 2 at their Groton, Connecticut shipyard. At that time, these two U.S. Navy- certified docks, which are used for drydocking and repairing nuclear-powered submarines, were over forty years old, and the failure of a section of sheet pile wall at Electric Boat's Graving Dock 3 had raised concerns on the part of both Electric Boat and the U.S. Navy about the condition and safety of all three of the shipyard's graving docks. After a comprehensive condition assessment and long-term life extension study, the decision was made to begin the design and construction of the life-extension project, which ultimately involved the placement of 37,000 cubic yards (28,288 cubic meters) of marine-grade concrete, 2,750 tons (2,495 metric tons) of reinforcing steel, installation of 260 high-strength tie-rods, and more that 100 rock anchors. This paper describes the challenges faced by the project team, from the design, to the environmental, coordination and scheduling during the construction.