Restoring Alignment to Distorted Stackable Modules

Civil + Structural Engineer magazine published a case study by Simpson Gumpertz & Heger (SGH) senior staff members detailing the condition assessment and repair of steel removable submarine covers (RSCs) at the Portsmouth Naval Ship Yard in Kittery, Maine. In “Restoring Alignment to Distorted Stackable Modules,” Diego Arabbo and Matthew Gilbertson explain how SGH performed a structural condition assessment and designed repairs for RSC components that fell during strong wind gusts.

The authors explain that RSCs contain modular wall stacks that, when bolted together, form an enclosure around a submarine to provide access to the submarine’s exterior and allow conditioning of the space. During restoration and modernization of the RSCs at a staging yard adjacent to the Piscataqua River, strong winds caused a fifty-foot-tall wall stack to overturn and fall into a stair tower module, damaging and distorting both structures. The contractor responsible for the restoration and modernization of the RSCs retained SGH to conduct a structural condition assessment of the damaged modules and design repairs, “with the unique challenge of verifying that the repaired modules could be properly aligned, assembled, and returned to service as part of the full RSC system.”

The article describes how SGH assessed the damage to the structures, developed sampling programs and three-dimensional models, and designed repairs for the contractor. Ultimately, the authors conclude, the “modeling and analysis procedures showed that all damaged modules could be repaired and salvaged.”

Read the article.