Dexion Ltd became established as the
foremost producers of slotted angles in the
world. This product is still as useful as ever
and millions of feet are made every year for
home and export. However, all products have
their limitations and there are some storage
jobs for which lightweight angles are not really
suitable. Dexion Ltd, recognising that their
business was not so much as slotted angle
manufacturers but more as storage specialists
have long now offered several highly developed
storage systems on the market. Most recent of
these is the Highbay system.
Basically the problem is that the cost of
land is ever increasing and in some areas the
shortage is desperate. In addition it is vitally
important for stores to be as efficient as
possible as obviously all time spent fetching
goods is non-productive and should be
reduced to a minimum. Similarly the more a
system can be automated the faster and more
efficiently it can operate.
The only way to save on land is to build
30 NSC
Jun 20
high – as high as other limiting factors such
as foundation conditions, wind pressures,
efficient operation of cranes, town planning
and costs will permit. The best way to save
in operating time is to have powerful cranes
to fetch the goods and working in a layout
presenting no obstructions to movement.
These features have been brought together
in the Highbay system designed and built by
Dexion. One of their contracts using these new
techniques is for Fords of Dagenham. Highbay
warehouse, also known as ‘Pallet Silos’
were first developed in the USA and are now
spreading into Europe. Basically they consist
a number of parallel pallet racks separated
by narrow aisles in which the stacker cranes
operate. There is no building in the traditional
sense of the word as the roofing and cladding
is simply attached to the tops of the columns
and the outermost racks. Clearly the aisles
should also be as narrow as possible and the
stacker cranes are designed to operate within
these narrow confines and at a high level.
FROM
Building
with Steel
May 1970
The Highbay warehouse at Fords is 131 ft
wide by 560 ft long while the height is 110 ft
to roof level with a further 2 ft for the parapet.
The racks occupy 507 ft of the length and are
so arranged as to provide a crane maintenance
area at the western end and a 106 ft pallet
marshalling area at the east in a low single
storey building. Altogether more than 3,000
tons of structural steel has been used, most
of it being mild steel and the remainder high
tensile. The ground is of a poor nature in
consequence of which every one of more
than 1,000 columns has an individual pile
foundation.
There are eight parallel racks, six of which
are double entry, while the two outer racks are
single entry and also carry the steel sheet wall
cladding. All the racks assist in carrying the
roof. In addition to carrying pallets the side
racks are 7 ft 6 in wide in order to resist wind
loads. The internal racks are 8 ft wide and give
support to the sides through the roof beam.
This beam is a 7 in × 4 in RSJ and not only ties
50 Years Ago
The high cost and scarcity of land
have led to the development of
Highbay storage systems.
R. Dunning, CEng, AMIStructE,
Senior Structural Engineer,
Storage and Materials Handling
Division, Dexion Ltd, here
describes a new warehouse for
the Fold Motor Co in which over
20,000 tons of goods can be stored
View down aisle from upper maintenance platform
TALL
STORAGE
Finished view of the building in
which no windows are necessary