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Structural analysis models typically include preliminary piping weight and friction loads. Smaller diameter piping (<12" NPS) are modeled using distributed gravity-direction loads on the beams based on tributary area, and larger diameter pipe loads are assigned as concentrated point loads or equivalent frame point loads. Structural models treat friction as an assigned load, typically 10% of the weight load. Friction is not treated as a load in piping stress models, but as a nonlinear boundary condition which is a more rigorous approach. All of these preliminary piping loads in the structural model ignore load redistribution due to thermal displacement and other applied loads. That's why structural engineers need realistic pipe support loads from the piping stress team which account for thermal displacements and nonlinear pipe support behavior.
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