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Meeting the Challenge for Portsmouth Naval Shipyard
INFRASTRUCTURE MARKET
n By Scott Jason
Portsmouth Naval Shipyard (PNSY), located in Kittery, Maine, is the U.S. Navy’s oldest continuously operating naval shipyard. Established during the administration of John Adams, the shipyard has a storied history; building and servicing ships, housing prisoners of war and even serving as the backdrop for an International Peace Treaty. For the last 100 years, PNSY has specialized in building and servicing submarines.
Due to the Navy’s operational requirements and the limited amount of shipyards with the capability to perform PNSY’s mission, contractors on the base must meet aggressive timelines, manage complex coordination challenges, and make schedule adjustments on short notice. Cianbro has been meeting these challenges at the shipyard with high-profile projects of increasing complexity.
Awarded in January 2017, the Caisson Replacement & Seat Repair was a mission-critical project to replace an existing dry dock door (caisson) and rehabilitate the dry dock seat. One of the challenges of the project was how to rehabilitate the dry dock entrance structure without taking the dock out of service. The solution would be what is called a limpet cofferdam. Limpet cofferdams are small cofferdams typically used in ship repair to effect in-water hull repairs. This innovative approach provided a dry workspace large enough to allow team members to complete concrete repairs below the surface without taking the dry dock out of service.
In addition to the seat repairs, Cianbro managed the construction of the new caisson at an offsite facility by our partner Steel America, as well as replacement of a sluice gate and conduit grate at the dock entrance, concrete repairs to the interior of the dock walls and the installation of a new dock stairway system. The project was successfully delivered on time in the spring of 2020.
Awarded in November 2016, Cianbro modernized over 1,200 feet of pile-supported open wharf structures in front of an active dry dock. The team installed a king pile-supported precast concrete shutter panel wall and sheet pile bulkhead. The challenges were schedule and logistics. The Navy had a “must meet” aggressive timeline to accommodate a fixed submarine berthing schedule, with limited shore side space to accommodate equipment, personnel, and material. Cianbro mobilized a significant portion of marine equipment including specialized jack up barges, deck barges and sectional crane barges with specialized cranes to reduce the shore side footprint. Through a partnering relationship, appreciation for the clients and needs and the commitment of the greater team toward the accomplishment of the mission, Cianbro substantially completed the project on time in March 2020.
In mid-2017, Cianbro was selected as the successful bidder for a submarine support complex. Shortly after receiving notice of award, the mission of the project was changed to meet the mission needs of the shipyard facility. For the next several months, the Cianbro team worked alongside with the PNSY Naval Facilities Engineering Command (NAVFAC) and engineering teams to get the new design and construction of the project under way in an unprecedented short window of time. The work was broken into packages and put into execution with amazing speed and efficiency. This project included the construction of multiple complex industrial buildings that required strict compliance and was surrounded by numerous other planned and ongoing projects. Portions of the work were subcontracted to specialty subcontractors with the experience in execution of this type of work for the Navy in the past. Structural steel, metal siding panels, electrical and controls, unique HVAC systems, etc. are just some of the critical pieces of work needed to deliver this project. Work continues on the complex as Cianbro works closely with NAVFAC, it’s engineers and shipyard customers to bring this unique project to successful completion.
Awarded in December 2019, the P-310 Superflood Project is the first phase of the largest and most technically complex infrastructure project the Navy has undertaken in years. The project involves constructing the foundational basin of what will become two new multi-mission dry docks needed to service the Navy’s future fleet of submarines. The work entails construction of large concrete filled cellular cofferdams to extend the existing structures, fabrication, delivery and installation of a more than 5,000-ton precast concrete entrance
structure, construction of temporary cofferdam cutoff walls, improvements to the existing granite wall via a sheet pile and concrete fill lining, dredging and rock blasting and removal, the addition of thousands of feet of landside concrete crane and trail rail systems, and modification to and addition of significant underground utilities needed to accommodate the initial superflood capability and the follow on future dry dock plans.
Cianbro continues to fully appreciate the importance of Portsmouth Naval Shipyard to the defense of our country and the freedoms that our armed forces make possible for us all to enjoy. We value the partnering relationship with NAVFAC as our customer as we focus on successful completion of the current projects and work on developing the best value option for future projects yet to come.
