Our rack engineers are often asked by rack users if it is safe to remove bottom beam levels in a pallet rack system to store double-stacked pallets on the floor. UNARCO informs users that this practice is not safe because the capacity of the frame is dramatically decreased. Without hesitation, the rack user then asks, “How about if we just remove the beam in every other bay? Then we still have the same column span.”
The answer to this question is, “No!” The reason the answer is No lies in the fact that when every other beam is removed, one of the fundamental assumptions that is used to compute the frame table capacity value is undermined. The rack frame capacity tables are developed with the assumption that a column span is framed by two beam connections at the top and either a base plate or two beam connections at the bottom. When every other beam is removed, half of the top-span restraint of the column is gone and the frame model is no longer valid which voids the frame table capacity value. The practice of removing every other lower beam span in a pallet rack system is no safer that removing every other first story beam in a multi-story building.