Design of Industrial Pipe Racks Using Modules, Pre-Assembled Units, and Stick-Built Construction

Pipe racks are important structures in industrial plants. They are used within or to connect operating units, or longer distance for plant extension operations. For a large industrial facility, it can be feasible to utilize combined construction methods ‒ modules, pre-assembled units (PAUs) and/or stick-built construction at job site ‒ to fit site conditions, logistics, and construction schedule. Engineering design of pipe racks varies depending on specific construction methods selected, logistical and feasibility study results, constructability, piping routing, and layout of process units. Structural framing layout, selection of member sizes and connection types directly affect material selection, construction, cost, and schedule. In addition to the consideration of operating (product contents, thermal expansion and anchor loads) and environmental loads (wind and seismic), the design of pipe rack modules requires the consideration of sequencing during shipping (by barge/ship or truck), and self propelled modular transporters (SPMTs), and installation (by crane or SPMT) that associate with different design loads, load combinations and load paths. The purpose of this paper is to present the unique design considerations of framing layouts, member connections, and related structural analysis using different construction methods in new and existing facilities. Design considerations including transfer forces, camber, SPMT supports, temporary members, lifting details, member splices, brace connections and column base connections are also discussed and presented.