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This unique capability becomes particularly important for realistic pipe-structure interaction since heavy equipment, cable trays, and other objects with significant mass are typically modeled as assigned gravity-direction loads in the structural model. Those gravity-direction loads need to be considered in the calculation of static acceleration loads and for analysis of all dynamic analysis cases. If a user builds a structural frame model or imports a structural model which includes loads from equipment, fireproofing, or other objects with significant mass, the ability to convert gravity-direction loads into mass becomes a critical consideration for analysis of static accelerations and dynamic load cases. If, for example, a user assigns a 450 kip gravity direction load on the structure to account for the weight of fin fan air cooled heat exchanger weight loadexchangers, that load should change the calculated natural frequency and also change the static seismic load calculation for that model.
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