THE OPPORTUNITY
PS&S was asked by the United States Navy (NORDIV) to redesign the 600-foot quay wall that serves as a berthing for the Navy’s submarine fleet and as a loading point for submarine support vessels. In addition, NORDIV requested a condition assessment of a timber-framed building adjacent to the loading platform. During the site survey and bulkhead condition survey, efforts were coordinated to have teams work around the clock to mitigate access and security matters. Similarly, the existing building assessment was performed to minimize operations at this important Federal facility. The site required PS&S to provide geotechnical, structural and marine engineering services, including dredging and seabed topographic services. The submarine base is located along the Thames River.
THE CHALLENGE
The site required the installation of 600 feet of steel sheet piling bulkhead quay wall to support the upland portion of the site and resist loadings from the moored vessels. The site also required dredging to depths that would allow submarine berthing as well as the dredging of a channel to access the quay wall. The project also required the design of a 10,000-square-foot operations building adjacent to the quay wall.
THE PS&S SOLUTION
This project is an example of the kind of efficiency and economies PS&S’ multi-disciplined approach to design and construction can bring to a federal project.
PS&S utilized the services of its seasoned in-house marine structural and geotechnical engineering staff to design a solution to the specialized loading conditions imposed by the submarine and submarine support vessels and the foundation challenges posed by the existing geologic site conditions. This resulted in the design of a stiff marine grade sheet piling system, with a rigid braced design at its corner terminus, capable of resisting large earth pressure loads resulting from deep dredging adjacent to the quay wall and from ship impact loadings. Detailed underwater soundings and soil sampling were required to dredge adjacent to the constructed wall and throughout the access channel leading away from the wall.