The approximately 38 ft tall by 6 ft dia. heat exchangers located inside the reactor building are supported at their base by reinforced concrete piers, steel columns, and concrete walls; and are laterally supported near their top by tie rod bracing. For this project, SGH performed a structural evaluation and designed the upgrade for the primary heat exchanger supports for Performance Category 4 (PC-4)/Seismic Design Category 5C (SDC-5C) compliance. Our upgrade strategy focused on maintaining the stiffness of the existing load paths to preserve the validity of BEA’s previous dynamic analysis. Upgrades include new:

• Upper tie rod bracing and ductile anchorage
• Steel jacketing of supporting concrete piers for lateral and vertical confinement
• Ductile lateral load path and base anchorage at the concrete piers
• Ductile lateral load path and anchorage at the walls

We prepared calculations, design drawings and specifications, and three-dimensional fabrication and assembly drawings. SGH delivered a formal presentation to our client and our design work was independently reviewed and accepted. We also provided construction administration services that included review of the temporary scaffolding system.