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| Shi_Ling_Bridge_Tonkin_Liu_Yunnan_model_2 |
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| The Shadow Pavilion by PLY Architecture showing how a thin planar surface can be rolled into an element that generates a distinctive building form |
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| The leaf roller caterpillar manipulates flat leaves into tubular forms by attaching threads across the surface and then shortening the threads in a manner similar to a ratchet strap |
Transformations of planar surfaces
The caterpillar uses this tube structure for a week, but recent research shows that it is then used by other organisms, and plays a significant role in increasing the density and diversity of arthropods. Similar ingenuity is evident in PLY Architecture’s elegant pavilion in Matthaei Botanical Gardens, Michigan.
Sheets of laser-cut aluminium were rolled into cones and then assembled based on patterns of phyllotactic geometry.
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| Shadow Pavilion Plan |
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| Shadow Pavilion section and elevation |
Plants have had to evolve ways to present large
amounts of photosynthetic surface to absorb light.
But a larger surface area needs more structuring, since
growing bigger leaves by increasing their thickness has
significant drawbacks.
Curves and folds have evolved to
create stiffer elements out of thin material.
In the case
of the Southern Magnolia, the fold occurs along the
midrib and each half of the leaf is curved . Both
the fold and the curve contribute to the leaf ’s stiffness.
In rain forest environments, daylight at forest-floor level
is scarce and many plants have responded with large
leaves folded into fan forms .
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| The Southern Magnolia leaf, stiffened through a combination of a curve and a fold |
The principle of using ribs to stiffen a thin surface may well have inspired engineers to design similarly efficient structures, and the concept could be applied widely.
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| Fan palm leaves – an elegant example of how folds can transform a large, thin surface into a structure that can cantilever from a single point of support |
Architects Tonkin Liu, working with structural
engineer Ed Clark at Arup, were inspired by the forms
of marine molluscs and techniques from tailoring
to develop a new form of construction derived from
planar surfaces. They refer to this as a ‘shell-lace
structure’ .
Just as in the molluscs, the
structure derives its stiffness from the articulation of
a thin surface: folds increase the effective structural
depth, curves create added stiffness and twists
provide a degree of triangulation.
The end product
is an extremely elegant structure, constructed with a
minimum of materials, deriving its strength from its
shape rather than its mass.
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| Diagrams by Tonkin Liu Architects showing how structural principles from shells were analysed |
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| The Shi Ling Bridge designed by Tonkin Liu Architects and structural engineer Ed Clark of Arup – an example of a ‘shell-lace structure’ that achieves efficiency of materials by exploiting vaulted, folded and twisted forms from shells |
"Shell Lace Structure is a technique inspired by nature. Seashells gain
strength from optimised curvilinear geometry, locking in stiffness with
corrugation. Lightness is achieved through perforation, creating
highly-efficient and responsive structures with minimum weight and
wastage. The technique has been developed through research and
experiment with digital modelling, digital analysis, and digital
fabrication tools. The design process is intuitive, analytical and
iterative. Three-dimensional geometries are built up virtually from
conjoined developable surfaces. These surfaces are unzipped at the
seams, unrolled and nested allowing efficient computer
aided cutting from a flat sheet material. The cut profiles are
reassembled to create the final three-dimensional form."
- https://tonkinliu.co.uk/shi-ling-bridge
Resources and further reading:
https://tonkinliu.co.uk/shi-ling-bridge
Book reference:
Biomimicry in Architecture by Pawlyn, Michael
Get the Book on Amazon:
https://amzn.to/3I8RHw0
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