Seismic-Proof Storage Racks
Built to sway, not snap.
Occasionally a concern arises as to how stack racks will perform during a seismic event. Static loads are easy to test, while dynamic loads are much harder to analyze. Anecdotal evidence shows that stackable pallets and stack racks made by Tier-Rack perform well under seismic conditions and impact, because they absorb the shock waves by swaying and moving across the floor.
Fixed racking vs. portable racks
See How Fixed Racking Fails
These videos show how standard bolted-to-the-floor pallet racking performs in these situations.
The science
Base Isolation
Engineers designing earthquake-resistant buildings use a technique called base isolation. The leading techniques “try to absorb a lot of the ground motion energy so the building doesn’t have to,” using base isolators that act like rubber mats, viscous fluid dampers that work like shock absorbers, or slide bearings that let the building sway instead of snap.
Source: Scientific American, September 2004, quoting James Malley, Degenkolb Engineers, San Francisco.
How our racks compare
Sway, Rock and Absorb
Our stacking pallets (sometimes called racks) perform in a similar way. They sway and rock and absorb the shock. We even have evidence of them scooting across the floor with the shock waves, but not failing.
Unlike the rigid structure of bolted-to-the-floor pallet racking, our racks’ relatively “loose” fit acts as a damper, providing the shock absorption needed to withstand impact more efficiently.
Codes & inspections
Steel Pallets, Not Structures
Each municipality interprets and applies the IBC (International Building Code) differently. Some inspectors don’t use it at all and apply different codes to determine whether a rack or bin design is suitable. Tier-Rack has no way of knowing this from township to township, so it is up to you to lay the groundwork. Much of the confusion comes from misapplying standard “rack” codes to our portable material handling pallets. “Racking” by definition is a structure bolted to the ground. Applying those codes to our product is as mistaken as applying them to a forklift.
Don’t let our name fool you
A Trade Name Since 1955
The name Tier-Rack was coined back in 1955 and is only a trade name. Our product is truly a steel pallet: portable and stackable. Like wooden pallets or crates, steel stackable pallets are equipment that protects product as it moves around a warehouse, and goods on them are commonly stored and stacked on the ground.
Their steel tube posts protect the product by supporting any steel pallets stacked on top, just like the wooden panels of a crate. They are not structures: there is no positive connection between the pieces, and they are meant for temporary storage, not permanent fixtures.
Documentation
Seismic Letter
Need documentation for your inspector? View or download our seismic letter.
In their words
Customer Testimonials of Seismic Performance
Questions about seismic requirements?
Talk to our engineering team about your location and inspector requirements, including P.E. stamps.
