Tying Racks to the Building Wall or Roof

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Warehouses often move rack around from the originally designed layout to help store items more efficiently or help SKU adjacencies. Moving pallet racking is not always safe, especially when double runs of rack are changed to single runs of rack and components of the system such as back-to-back row spacers are removed.

In many cases, Warehouse Managers may decide to tie single-runs into a wall instead of the existing racking that it was designed to tie into. Is it a good idea to tie a pallet racking system to the building structure or walls? This question will often come up when the height-to-depth ratio of the single row of pallet rack along the wall exceeds the RMI limit of 6 to 1 or when a rack user wishes to use a set-back or slope-leg frame detail in a single row along a wall.

The latest RMI Specification discourages the use of wall ties because the building and the storage racks are each designed with their own structural system to resist seismic forces. When the two systems are tied together it can change the behavior of both systems. Forces from the racks are applied to the building through the wall ties and forces from the building are applied through the ties and into the storage racks. Technically, a structural analysis of the two systems as a combined system should be carried out if the two systems are tied together which can be a very expensive and complex engineering analysis, and sometimes cannot always provide an exact answer.

Wind forces into the building can also make their way to the rack through the ties. If the rack is tied to the roof, snow and rain loads, or roof wind suction can also cause force on the rack system. There is a lot to consider and analyze.

Unless your system was clearly designed to tie into building structures by a qualified structural engineer, it is recommended to avoid wall ties. If a single row height-to-depth ratio exceeds the 6 to 1, there are other design options available which include a larger baseplate and a stronger anchoring scheme or cross-aisle ties to tie the rack into another row that is across the aisle. Both of these options will help the system resist overturning and should be considered before the use of wall ties.