How to create efficient architecture structures through Biomimicry ? (Web / tension structures)

 

 

The bowl and doily spider’s dining arrangements

Webs built by spiders have inspired a number of modern architects and engineers. Their forms range from the commonplace webs created by household spiders to the remarkably architectural tension structures of the grass spider (genus Agelenopsis) and the bizarre constructions of the bowl and doily spider (Frontinella communis) and the female bauble spider (Achaearanea globispira).

 

Web made by the grass spider – a tension surface spread over grass ‘masts’

 

Arguably, there is no greater champion of tension structures than the German architect and engineer Frei Otto (1925–2015). He pioneered cable-net buildings and, through the Institute for Lightweight Structures that he established, published 32 volumes on structural design principles from nature.

Comparing spider webs with cable-net structures, which are apparently very similar, reveals the gap that exists between biological manufacturing and our engineering: the relatively large sizing of the cables and the very visible connections being obvious differences.

However, this is a gap that is narrowing all the time and, as we develop more sophisticated materials manufacturing and adaptive structures, we should be able to get closer to the elegant arachnid exemplars.

House of the female bauble spider, apparently under the influence of Bruce Goff

The West German Pavilion at Expo 1967, Montreal by Frei Otto – perhaps the closest we have come to the elegance of spiders’ webs

The most common form of tension structure is a cable net, which generally involves a series of guyed masts from which the web is suspended.

Although it uses more substantial vertical elements than the tent-type schemes, Kenzo Tange’s brilliant Olympic Gymnasium in Tokyo is essentially the same.

The Grimshaw team, for the proposed third climatic enclosure at the Eden Project, pursued a different approach. The imperative design requirement for this enclosure was for it to achieve the highest possible light levels.

This led the team to explore an approach that placed the heavier compression members around the perimeter of the building, while over the growing area the most minimal arrangement of tension members would be stretched.

The Dry Tropics Biome used a distorted lattice ring-beam to form an anticlastic surface, such that at any point on the surface the cables, and the membrane that they support, would be tensioned in two directions for maximum resistance to wind loading. 

 

Tokyo Olympic Gymnasium by Kenzo Tange – a distinctive form created with just two masts and all the remaining primary structural elements being tension cables

 

The Eden Project Dry Tropics Biome by Grimshaw. The scheme aimed to maximise light levels inside by using a ring beam to stretch a minimal web of cables over the growing area

Book Reference:

Biomimicry in Architecture by Pawlyn, Michael
https://amzn.to/3GgvxGy