Seismic mitigation efforts, which began in February 2023 on the Trident Refit Facility at Delta Pier in Bangor dry dock, have been completed.
In January 2023, the US Navy restricted submarines from entering certain dry docks in the Pacific Northwest (both at Puget Sound Naval Shipyard & Intermediate Maintenance Facility and Trident Refit Facility – Bangor) because of seismic concerns identified in recent studies. The US Navy subsequently deployed and implemented a repair technique using dry dock wall reinforcing tie downs.
The three dry docks where tie downs were installed have been recertified. Repairs to the full length of the Bangor dock walls have been completed and the dock was recertified 10 August 2023.
PSNS & IMF’s Dry Dock 5 was recertified on 30 June to dock USS Connecticut (SSN 22) and Dry Dock 4 was recertified 28 April to dock USS Pennsylvania (SSBN 735).
Construction efforts include drilling holes for the installation of anchors inside the dry dock walls to enhance structural integrity and ensure the safety of the workforce, community, environment and submarines. The mitigation efforts updated existing emergency response plans to better address the chance of a catastrophic earthquake, along with improved early warning employee notification systems in the dry docks.
Experts from industry, Naval Sea Systems Command, Naval Facilities Engineering Systems Command, TRFB and PSNS & IMF planned and implemented the structural upgrades, with an eye on the US Navy’s future needs.
The short-term mitigation actions did not affect the strategic deterrent capability of US forces or the ability of the fleet to continue its mission. PSNS & IMF remains the primary provider for the maintenance, repair, modernisation, inactivation and disposal of ships, submarines, and nuclear-powered aircraft carriers in the Pacific Fleet.
Based on future planned improvements to Dry Dock 6, and differences in ship design and the size of aircraft carriers, it was determined immediate seismic mitigations are not required. Aircraft carrier maintenance at PSNS & IMF remains unaffected. The need for mitigations in the remaining docks will be determined once current efforts are complete and may include stability enhancements for submarine availabilities.
