Introduction to pleating
Pleating refers to the practice of folding a fabric into
parallel strips - known as pleats.
Examples of pleated structures
Exteriors. Many more exterior views are available here.
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| Komatsu dome
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| Odate Jukai dome
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Tropicana Field
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Interiors. Many more interior views are available here.
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| Komatsu dome
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| Odate Jukai dome
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| Tropicana Field
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Pleating
Pleated membrane structures are a common type of
architectural construction - in Japan.
Pleating replaces the high points used in many tensile
membrane structures with high lines.
The pattern provides regular structural support to the
membrane, using cables.
Such a pattern typically involves parallel cables - with
valley cables pushing the fabric downwards from above and
ridge cables pushing it upwards from below.
The result is a surface which appears to be regularly
folded.
In some ways, pleating is the tensile version of
corrugation.
Advantages
There are many advantages to using a pleated pattern:
- Strength and span: the limit of the
tension in such a membrane surface is limited by the
strength of the steel cables - rather than by the tension
capacity of the membrane itself - allowing for much tauter
fabrics than would otherwise be possible.
- Low profile: near-horizontal surfaces can be employed. The membrane
itself is not near horizontal, and the high tension cables
are effective at preventing pooling - eliminating spots
where rain water might otherwise collect.
- Flat panels: the pattern lends itself well to flat, rectangular
frameworks. These are commonly used in buildings - most
walls, floors and roofs in the world consist of what are
essentially flat panels, or composites of them.
- Economical: the near flat surface saves
material compared to use of a pattern with high points.
- Proven: the pattern has demonstrated
utility in the field - and scales up well. Many large
pleated structures exist - including one of the largest
clear-span structures in the world: the 209m diameter
Tropicana Field.
- No patterning: if using a
slightly elastic material, structures can be built
that use the elasticity of the material as the source of any
anticlastic curved surfaces - as is done in polytunnels.
This approach means that sewing or welding the fabric into
complex shapes can be dispensed with - and a simple flat
sheet can be employed.
- Simple patterning: if use of a flat
sheet is not possible, patterning using simple
strips may be effective.
Often the use of simple patterns - like these:
Vertical strip pattern
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Horizontal strip pattern
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...may be possible. Use of such simple strip patterns helps
to eliminate offcuts, and simplifies stitching and welding.
- Flexible: clyindrical and conical
shapes are well suited to the approach.
- Shingling: shingling works well with the
pattern - reducing the need for water-tight welding.
Shingles
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- Retractable roofing: use of pleating
offers a number of opportunities for creating retractable
roofs and reconfigurable surfaces.
Disadvantages
- Stability:
while pleated patterns with doubly-curved anticlastic surfaces are
possible, pleating mainly represents an alternative approach
to stabilising a fabric - supporting it regularly with high tension
cables.
However, unless some kind of curved surface is used for the
membrane, its surface is likely to have a tendency to
oscillate.
While the pattern encourages the use of flat surfaces - to
avoid complex anticlastic patterning issues - there are
disadvantages to going too far in this direction -
since completely flat surfaces are the ones most prone to
vibration and rippling.
- Cost:
while the pattern is economical on fabric, it does
use additional cables - and sometimes struts.
The materials
and detailing associated with these will have its costs.
- Time:
the pattern may have some of its overheads in areas which
affect construction time on site - rather than being
confined to the factory - if there are cases where the cable
network can't easily be pre-constructed on the ground before
being lifted into place.
- Aesthetics:
the pattern's lack of large anticlastic surfaces means that
it lacks some of the aesthetic properties associated with
most tensile architecture - and may not produce such a
distinctive profile against the sky.
On the other hand, it looks less like that well-known low-
budget structure, the tent.
Other applications
Pleating has many familiar applications.
There's a page devoted to those on this
site.
Other applications page - thumbnail
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