Best Practices Magazine - issue nº1 - English

Our experts I Structural Calculation
How to calculate the structure
of a conventional pallet rack
What forces must be pondered when designing metal pallet racks? How do we verify that the structure
will be suitable to withstand all loads? These and other issues are those which should be taken into
account in the design of this type of rack, with the goal of ensuring its stability and resistance, and
therefore the overall security of the installations.
The European EN 15512 norm, according
to its definition, specifies the requirements
for structural design applicable to conventional
pallet racking (selective racks)
manufactured from steel components,
designed to store palletised unit loads and
subject to essentially stationary loads. It
has become the main benchmark on this
matter, and provides additional technical
information required for the implementation
of the Eurocodes.
In addition, designers must also provide
for the EN 15620, EN 15629 and EN 15635
standards as guides for the specifications
of the storage system, the required tolerances
during assembly and the safe operation
of the installation.
Likewise, conventional racks for palletised
loads are metal structures, generally
formed by components made out of thin,
cold-formed, steel sheet metal. They are
able to withstand heavy loads, while the
installation is designed to be as lightweight
as possible; consequently the rack’s own
weight rarely exceeds 5% of the load stored
in the facility’s interior.
On the other hand, it is imperative that this
type of installations for palletised loads be
versatile, to be able to adapt to different
load types. For this reason, the connections
between the main parts of the structure
must be adjustable, and quick and
easy to assemble.
The uprights of these structures usually
have perforations along the entire profile,
while the beams include connectors provided
with hooks that fit into the perforations
of these uprights.
Basic structural
components
• Frames: are vertical pieces composed
of two uprights joined together by beams
and cross-ties forming a lattice.
Close up of the
joining of an upright
and a beam
• Uprights: these tend to be cold-profiled
components of thin sheet metal, with
open sections and are always perforated,
which makes them prone to distortion and
torsional type sagging.
• Beams: are horizontal pieces that bear
the burden of the pallets. These tend to
be cold-profiled and have connectors on
their ends for attaching them to frame
uprights.
• Connectors: are parts welded onto
the ends of beams to attach them to the
uprights. They are equipped with hooks
that fit into the perforations of the
uprights.
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