There’s a lot of confusion surrounding wire decks and load distribution and for good reason. When wire deck capacity is listed, for example, is the manufacturer referring to the wire deck itself, or the deck in combination with the beams it’s sitting on? Is the capacity the same regardless of the type of load? What about the shape of the support channels? These are all common questions, and we’ve worked to address them in other wire deck articles. Some of the most common, and often some of the most important questions we encounter are those related to wire deck capacity and load distribution. In other words, customers need to know how wire deck capacities change when the weight-bearing area of the decks changes. These questions are important because their answers can directly affect how the decks are used. This information helps prevent end-users from misusing or overloading decks and helps everyone involved gain a better understanding of the decks’ true weight capacity.

The rule of thumb to remember when reviewing a customer’s load capacity for a given wire deck is that it is important to make sure the load is uniformly distributed. Capacity ratings are usually based on Uniformly Distributed Loads, i.e. loads that are evenly spread across the surface of the deck.  If a customer has a line, concentrated or point load, this is considered a Non-Uniformly Distributed Load, and the original deck capacity will no longer apply.  This type of load may require a special design to avoid the risk of failure. To make sure there’s no confusion, let’s review some of the definitions of these different types of load distribution.

Uniformly Distributed Load (UDL)

UDL refers to any static load which is evenly distributed over the entire surface on the rack deck.  This means the product being stored on the deck must cover the entire deck from side to side and front to back.

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Uniformly Distributed Load

Line Load

Line load refers to any static load which distributes its weight in a concentrated line. For example, a load on a pallet which only has two boards running parallel with the wire deck channels would be considered a line load. In this situation, it could cause the wire to carry the entire load.

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Line Load

Concentrated Load

Any static load which is not uniformly distributed over the entire surface of the decking section.  For example, a 2500# barrel placed in the center of a deck would be a concentrated load, because the entirety of the barrel’s weight is placed in one area. The rating of the deck would be significantly reduced.

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Concentrated Load

Point Load

Any static load that is concentrated on particular points on the deck. The most common example of a point load application is a heavy piece of equipment that has small feet. In this example, the weight of the equipment is so heavily concentrated in the relatively small feet, that it causes visible sagging.

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Point Load

Now that you’re more familiar with wire deck capacity and load distribution, you can apply this knowledge by confidently choosing wire decks that are appropriate for the application they’ll be used for, and also discourage use that may compromise the decks’ structural integrity and become a safety hazard.

Source: Rack Manufactrurers Institute