It's probably no surprise that exhibitors at the ProMat 2011 Show in Chicago found themselves fielding a lot of questions about their products' ability to withstand earthquakes. The show opened just 10 days after the earthquake and tsunami hit Japan and about a month after a similar quake shook New Zealand.
Exhibitors of pallet racks, mezzanines, and other storage systems were ready with answers. That's because manufacturers that sell warehouse storage equipment in areas prone to seismic activity like the U.S. West Coast must offer versions of their products that meet earthquake-related specifications in state and local building codes. Those versions must also be able to resist the horizontal motions that translate into the "moment forces" that earthquakes typically exert on a structure and its base, said John Moore, vice president marketing and systems development for Cubic Designs, a manufacturer of storage mezzanines.
On mezzanines, for example, this affects the design of the column tops, the column bases, the way the columns are attached to the framing, and the strength of the framing. Welds must be longer and stronger, and plates and framing members typically must be thicker than on ordinary versions, Moore said in an interview at ProMat. Building codes also specify minimum load capacities and minimum degrees of "deflection," or flexing, required to ensure the integrity of these structures. In addition, mezzanines' footings might be required to have extra bracing, depending on the flooring and soil conditions beneath the warehouse, he added.
Similarly, pallet racks used in seismic areas must have certain types of bracing, welding, anchoring, and connections. One rack manufacturer, Ridg-U-Rak, has developed a patented "seismic base isolation" system to prevent racks and their contents from falling during a quake. Watch a test of the system and a separate video showing the system's components and installation.