NISMO Philadelphia Wharves and Pier Rehabilitation Design-Build
The Naval Inactive Ship Maintenance Office (NISMO) is one of four holding facilities in the United States for inactive Navy vessels. The Navy retained us and Triton Marine Construction, under a design-build contract, to rehabilitate approximately 8,200 linear feet of timber pile-supported wharfs and also Pier 4, a 1,150-foot timber and steel pile-supported structure. The Navy identified repair of the Pier 4 concrete deck as its highest priority to allow ship decommissioning operations to continue safely and efficiently. Pier 4's current mission is the decommissioning of the aircraft carriers USS John F. Kennedy and the USS Saratoga.
Following initial visual investigations of the deck surface, it was determined that additional in-depth investigations and structural analyses should be performed to gather answers for the apparent deterioration of the pier. Defining safe operational parameters for the decommissioning contractor was also a key concern.
Field investigations, laboratory testing and structural analyses were performed, including visual above- and below-water evaluations, petrographic analyses of concrete cores and microbiological analyses of the timber piling. Condition assessment and subsequent analyses indicated Pier 4 does not meet Navy design standards for a Type IV facility mooring.
Complete demolition and reconstruction would cost between $40 and $50 million. The team developed nontraditional concepts for narrow deck travel corridors and crane lift areas, with mooring and breasting structures placed within the pier's existing footprint. The conceptual repairs were tailored to the Navy's needs and budget, providing a functional facility to withstand Type IV mooring loads.