Navy Yard Pier 6A: Rebuilding for the Navy’s Future

At the Philadelphia Navy Yard, the replacement of Pier 6A is preparing the Delaware River site for a unique future purpose: shipping Naval submarine components on a transport shuttle fabricated by Rhoads Industries. Working with customer GMAC, Silvi Materials supplied ready mixed concrete for the project, which involved the complete demolition and replacement of the existing pier.

Reconstructing Pier 6A required extensive work both above and below the Delaware River. The project included dredging the existing riverbed, installing sheet piles around the perimeter of the existing pier, demolishing the existing structure, driving 120 20-inch by 120-foot pipe piles, installing precast fascia panels with tie rods, backfilling the pier, placing rebar, and pouring the 36-inch pier deck to final grade. Two dolphins on 20-inch pipe piles with H-pile fenders were also installed in front of the pier for the shuttle to tie off to when loading materials. At the bottom of the river, three jacking pads were installed, each consisting of 12 pipe piles cut to mudline with a 20-foot by 20-foot concrete tub to support the sea shuttle at the final height of the pier for loading the Naval components.

Adding to the complexity, the cofferdam and underwater work had to take place within an active Naval yard and within an eight-month permitting window for riverbed disturbances. To meet the accelerated schedule, a prefabricated cofferdam was designed and fabricated offsite before the permit window began. The cofferdam frame was then lowered into place and reused at each jacking pad location, accelerating the work and allowing all permitted work and riverbed disturbances to be completed ahead of schedule.

From the reconstruction of the pier deck to the concrete tubs installed at the bottom of the Delaware River, Pier 6A highlights the role of ready mixed concrete in a project being built to support the future movement of Naval submarine components.