Efficiency of Nature and Its Impact on Biomimetic Architecture

Introduction

Architects and designers have continuously been inspired by nature throughout history. They have replicated the designs and patterns found in nature for ornamentation as well as for the forms of the buildings. Biomimetic architecture is also inspired by nature but rather than simply copying its aesthetics, it looks for functional solutions in nature. Biomimetic architecture therefore can be defined as an act of reproducing the functions or actions in nature and using it to solve architectural problems.

“Nature does nothing uselessly” - Aristotle

One of the primary advocates of biomimetic architecture is the fact the nature has a gigantic experience of 3.85 billion years in evolution and problem-solving. Currently one the major challenge faced by architects and designers throughout the world is to build a sustainable future by reducing our resource consumption. Our flora and fauna has some spectacular structural examples which are very efficient in terms of their use of material and took years of evolution to achieve it. Architects, therefore, search for answers to their complex questions by studying and replicating the forms in nature with intention of creating better and more efficient structures. This paper focuses on determining if these bio-inspired structures are actually as efficient as the natural forms they are inspired from and what we consider efficient in nature can also be considered efficient in terms of design and engineering?

Efficiency of nature

Through various biological observations, we can establish that nature is extremely economical in use of materials. It uses various techniques such as vaulting, folding, ribs, etc. to reduce the use of materials. One of the great examples of this efficient use of the material is hollow tube structures commonly found in nature. In a study, it was established that a solid material of square cross-section with a side of 24 mm has the same bending resistance as a hollow tube section of 25mm diameter but the latter requires 80 percent less material. In this particular case, efficiency is achieved by removing the material from areas where it is not required and only putting material in the areas which are under structural stress.

The bamboo plant uses a similar principle of only putting the material where it is required with hollow tubes to achieve large heights up to 42 meters. The tube structure in the bamboo plant is divided into small nodes which provide support against bending.

Other complex biological structures like trees follow similar principles for efficient use of material on a much larger scale. Theoretical physicist Claus Mattheck studied the growth pattern of trees for years and established that the growth of trees is as per one simple rule which he explains with a principle called the axiom of uniform stress. The trees biologically accumulate material in areas which are under strain to evenly distribute forces and therefore the areas under less or no strain have no material. The shape of the junctions or the connecting between the branches are also optimized in a way that it avoids stress concentration. Therefore, the overall structure of the tree is very efficient as there is no wastage of material and all the material being used bears its portion of the load. These efficiency principles of trees can be used to improve our conventional way of structural designing which determines the entire cross-section of the beam or column through the maximum load it needs to bear and therefore a lot of material being put in the structure is not actually required.

The study of bone structures of some of the animals has also shown great examples of reduction in dead weight in order to achieve lightness. Birds, in particular, have evolved over time to reduce the skeleton weight without reducing the strength and the study of skulls of crows and magpies have shown a space frame-like structure with two layers of layers of thin membranes connected by struts and ties like small sections. Some birds have even developed dome shape connecting structures between the membranes which are even more efficient than struts and ties like connection. This type of bone structure is a really good example even for engineering as it can help us to achieve large lightweight spans of surfaces with minimal use of material.

After studying all these examples, we can establish that evolution has made nature very efficient in terms of material usage and the forms in nature can help a lot in the advancement of the structural aspect of architecture. However, we need to further study how architects and designers are taking inspiration from nature and if the design output can actually be considered more sustainable than conventional architecture.

From nature to design

The influence of nature on architecture can be traced as far back as the origin of Western architecture. This influence was not only limited to the shape and appearance of the building but also determined its proportions. The use of the golden ratio which is derived from the patterns in nature can be clearly seen in ancient man-made architecture such as the Greek temples. However, biomimetics in architecture started with Buckminster Fuller’s work on the development of a geodesic dome and Frei Otto’s research on membrane surfaces. Frei Otto’s well-known research on soap bubbles focused on the relationship between form and forces in nature. He used his research to develop designs for many membrane structures and for the 1972 Munich Olympic Stadium. His research helped him to achieve better structural efficiency and to reduce the use of material by creating minimal surfaces.

Frei Otto in the 1970s also experimented with branching tree-like structures aimed at the uniform distribution of the force like an actual tree. He used this study to replace the column and beam structure with a tree-like branching column in a project in 1979. After this, the branching column design was used by many architects in large-span structures and the design of these columns was significantly rationalized using computational methods. Some studies also used genetic algorithms to optimize the load distribution in these structures.

A more recent example of a branching tree-like structure can be seen in the work of designer Joris Larman which computational modeling to achieve optimized biological tree-like structures. The first step of optimization uses ‘soft kill option’ software which removes the material in areas with zero stress and the second step uses ‘computer-aided optimization’ to refine the shape and add up material where there are chances of structural failure.

Efficiency in architectural design

We have already discussed some of the ways in which bio-inspired structures translate the efficiency from nature to design but to determine how efficient these structures are in comparison to our conventional structure, we need to look at different parameters required for creating efficient architecture.

Complexity of nature

'In nature materials are expensive and shape is cheap.' - Julian Vincent

Biology and nature are quite complex and although we continue to use principles derived from nature, it does not necessarily mean that we completely understand it. If we go back to the example of a tree which inspired some architects to make branching structural columns, we are only looking at one of the many phenomenons which influence the form of the tree. The form of the tree is also influenced by ease of transportation of fluid from roots to leaves and to maximize the sunlight falling on the leaves which requires that no branch should shade the branch below it. Therefore, simply copying the form of the tree without understanding its complexity cannot be very efficient.

Art historian Christina Cogdell has written quite extensively about architects and designers using principles of biologization in their work without completely understating the complexity of biology. Designers using generative algorithms and evolutionary computation often exaggerate biologization as they lack a complete understanding of biology.

Nature at times can also be really extravagant which has also been a source of inspiration for many architects. Architect Santiago Calatrava, for example, is quite well known for his use of skeleton structures and other bio-inspired forms but by no means can his work be considered economical or efficient in terms of material usage.

Calatrava also used a tree-like branching structure in one of his projects but his approach is more focused on creating aesthetics rather than making an efficient structure. Even if the structure is completely efficient and optimized to create the desired form, one could still argue that the form in itself is not rational in terms of creating material-efficient architecture.

Conclusion

Nature and biology are quite complex and the evolutionary process of nature is not just focused on consuming less material but also on other biological requirements such as gathering food resources, avoiding predators, reproduction etc. As explained with the example of tree-like structures, the forms in nature are much more complex than we assume and if we focus on only selective aspects of these forms then it might not give us desired result. Even though forms in nature are quite efficient in terms of material used but it does not necessarily mean that the forms derived from nature are also efficient and sustainable.

References

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