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Rack: Secure rack against seismic events

In the wake of catastrophic earthquakes around the world, and here in our own backyard, Modern looks at how to keep warehouses and distribution centers standing tall in the event of a seismic episode.
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At this testing facility, the goal of seismically engineered rack is to make it able to absorb the shock caused by a seismic event.

By Lorie King Rogers, Associate Editor
February 01, 2012

Terra firma isn’t all that firm. Every minute of every day there’s an earthquake rumbling beneath the surface of the earth. In fact, the United States Geological Survey (USGS) locates about 50 earthquakes daily, or 20,000 annually. However, it estimates that millions of earthquakes go undetected each year because they happen in remote areas of the world or measure such a small magnitude on the Richter scale.

Those earthquakes aren’t the ones that worry us.

Here in the United States, in 2011 alone, we experienced 22 earthquakes measuring between 2.9 and 7.3 in magnitude.

And they happen in all states, not just California. From Alaska to Alabama, Oregon to Ohio, an earthquake can hit anywhere at anytime.

“The earth is always shaking and moving,” explains Sal Fateen, a structural engineer and the president of Seizmic Material Handling Engineering. “It’s actually a good thing for the earth to release tension, but the problem is that nobody knows exactly when the earth will decide to misbehave.”

That erratic behavior can wreak havoc with our warehouses and distribution centers if we aren’t prepared. Rack systems that support the materials handling industry are particularly vulnerable to damage caused by seismic events. But, there are strategies and solutions that can protect people, property and products.

Identifying high-risk seismic areas, conducting inspections, and keeping rack equipment in good repair can help minimize the damage caused by an earthquake.

Seismic areas
Over the years, high- and low-risk seismic zones have been identified based on history and testing. Being in a low-risk area, however, doesn’t guarantee you’ll be spared. For example, in October of 2011, low-risk southern Texas experienced a 4.8 magnitude quake.

Still, the zones are a valuable guide. “When we consider seismic forces, we reference the zip code of where the rack will be built, and, depending upon the area, significant upgrades may be required to comply with the seismic forces,” explains Bob Novak, area market manager for Interlake Mecalux.

But because every rack installation is unique, there are no hard and fast rules for specific upgrades in any particular area. According to Dave Olson, national sales and marketing manager for Ridg-U-Rak and president of the Rack Manufacturers Institute (RMI), highly refined values for specific locations, which are publicly available, weigh heavily into rack designs. And, along with the rack structure height, depth of the frame, load weight, application, and type of rack, these values play a vital roll in seismic consideration.

The purpose of the identifying high-risk areas and establishing building requirements within those areas, however, is not to “earthquake-proof.”

According to Fateen, that’s not possible. The purpose is to minimize the damage that may occur from an earthquake. “It all boils down to developing a force that gets applied to a structure. Once you get that force, you have to develop equipment that can stand up to the test,” he says.

The force is calculated using a formula that includes a number of factors. While the calculations are extremely complex, Fateen explains, the force is a percentage of the weight of the structure and the load it carries. The rack structure has to be designed to resist the forces applied to it, including seismic ones.


Iron Mountain: Still standing in the wake of a quake

On Feb. 27, 2010, an earthquake measuring 8.8 on the Richter scale rocked the South American country of Chile. It was the world’s sixth most powerful quake ever recorded and lasted about 2 minutes—long enough to claim hundreds of lives and cause an estimated $30 billion in damage to residential property and commercial businesses, including Iron Mountain.

For more than 60 years, Iron Mountain has protected the vital records of more than 1,200 businesses around the world. Its dual-campus in Lampa, Santiago, includes high-height record management facilities with large selective rack systems used to store massive quantities of paper documents. Damage from the earthquake resulted in Iron Mountain razing seven buildings and the racking systems in each.

But one of its buildings, a 1.4 million-box warehouse with a multi-level, high-density rack installation (Interlake Mecalux, interlakemecalux.com) still under construction, stood tall. Because it wasn’t yet complete, it wasn’t carrying any loads. However, subsequent inspections concluded that it would have remained undamaged had it been completed and loaded.

While the company suffered damage, Iron Mountain was one of few businesses able to remain productive in the earthquake’s aftermath; literally a port in the storm for clients looking to relocate their important documents to secure facilities.

Faced with the urgent job of simultaneously rebuilding and growing its business, Iron Mountain turned to the supplier to build two maximum-capacity warehouses because, according to Doug Berry, Iron Mountain’s director of construction and facilities, its proven seismic designs that have stood the test of time and the test of an earthquake.

About the Author

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Lorie King Rogers
Associate Editor

Lorie King Rogers, associate editor, joined Modern in 2009 after working as a freelance writer for the Casebook issue and show daily at tradeshows. A graduate of Emerson College, she has also worked as an editor on Stock Car Racing Magazine.


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