Portsmouth Naval Shipyard (PNSY) P-381 Multi-Mission Dry Dock #1
Kittery, Maine
Project Description
381 Constructors, a joint venture between Cianbro, TIC and Middlesex Corporation, is under contract to construct the P-381 Dry Dock project at Portsmouth Naval shipyard in Kittery, Maine. Part of the Navy’s Shipyard Infrastructure Optimization Program, the multi-mission dry dock construction project will extend the depth and size of the docks that support the maintenance and overhaul of Virginia (VA) Class submarines. Through expansion and reconfiguration of the shipyard’s Dry Dock 1 area, the project will increase the capacity to maintain, modernize, and repair the Navy’s attack submarines.
Work on the dry dock, which will be used for the Los Angeles- and Virginia-class submarine programs, is expected to be completed by June 2028, according to the contract announcement.
381 Constructors will build a partitioned addition to the shipyard’s Dry Dock #1 which will consist of two bays, labeled Dry Dock #1 North and Dry Dock #1 West. Both of the bays will be large enough to support the maintenance and overhaul of Virginia-class submarines.
"New construction will include concrete floors, walls, and center wall separating Dry Dock #1 North and Dry Dock #1 West, new pump well systems, pump station building, two caissons, portal crane rails, mooring hardware, mechanical and electrical utilities, utility tunnels, and all appurtenances required to ensure an operational dry dock," the contract announcement states.
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Our Role
Hatcher Technical was engaged by P-381 Constructors as a consultant to assist in reviewing the design documents for the precast monoliths that form the twin dry docks structure. The monoliths are heavily reinforced engineered structures that include reinforcement extending into a cast-in-place stitch pour, requiring each monolith to be integrated with adjacent monoliths to avoid conflicts in the stitch pours.
Hatcher Technical conducted a constructability review of the monoliths, highlighting areas of high congestion and constructability challenges to be resolved. We produced partial models of the most challenging areas to facilitate discussion with the design and construction teams, and we contributed alternative reinforcement configurations to mitigate the construction concerns.
Location
Portsmouth Naval Shipyard
Kittery, Maine
Owner
United States Navy
Naval Facilities Engineering Command
NAVFAC Mid-Atlantic
Contractor
381 Constructors (Joint Venture)
Cianbro Corp.
TIC (a Kiewit subsidiary)
Middlesex Corporation
Designer
Stantec
Total Contract Value
$1.7 Billion
Timeline
2021 - 2028
Construction Method
New twin dry dock constructed from 27 precast concrete monolith structures, floated in to position, then stitched together with cast-in-place joint pours.
