ENTWINED DURABILITY Brandon Pun Professor Kihong Ku ARCH-413: Experimental Structures Fall 2017
Interwoven Modularity and Structural Integrity Brandon Pun ARCH-413: Experimental Structures Fall 2017
BRANDON PUN
ABOUT THIS BOOK This book is designed to support a theory that was designed for an expirmental structual, theory course. A partner and I supported a theory about woven forces and continued to work it through a series of processes. The development assisted in helping explore the aspects of architectural design and experience new and innovative ideas. Visit brandonpun.myportfolio.com for more information.
Table of Contents Introduction
5
Materiality & Structure
6
Bending-Active Structures & Weaaving
12
Modularity
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Conclusion
20
References and Acknowledgements
20
Introduction
Final Facade Prototype Model
COMPUTATIONAL DESIGN
Since humankind first created shelter with post and lintels, knowledge on construction and the formalities of creating a built environment for multiple purposes has expanded greatly. Structures grew larger, sturdier, and eventually began to tower over the societies that we lived in. With this ever growing knowledge, the structures of the world began to grow upwards rather than out in order to save space. Due to this, the materials used became lighter yet stronger; versus, the heavy, stone structures that still stand today. Focusing on the structural and aesthetic qualities of a structure, this paper looks to assess the possibilities of rethinking the exterior facade system. Making use of the advancement of modern technologies, modular facade systems can be utilized with less, and lighter materials with similar strength of form; with, a focus on interwoven materials to create strength, and the flexibility of these materials in terms of stiffness. This can be done through studies on the structural qualities of lightweight materials such as wood for a focus, experimentation with weaving these materials together and whether they would create a stronger form in comparison to current building techniques, and on the modular qualities of these studies and their connections.
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Materiality is arguably the most important part of design, as it is the basis of our initial limitation. It is through the behaviors of materials that form is created. The material form is connected to not only internal constraints, but external forces acting upon it.1 While there are many ways of creating a design through digital fabrication and means, it is only possible to imitate in a physical world with the understanding of forces and the limitations of each material’s properties. Digital design opens up a completely new way of organizing a structure, expanding the boundaries that were put in place in the past. While many see this as a way of creating intense, unrealistic structures, digital fabrication provides the possibility of integrating physical properties and material behaviour as a driving force behind the architectural design process.2 In this fashion, form, material formation, and structural performance are thought of together throughout the process. With digital fabrication and modeling, the elements of a material can be defined by their behaviour and limits rather than their shape or length.3
Original Anti-Clastic Design
Double Curved Shell Design
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While many materials such as concrete or metals such as steel are able to be formed to near any specifications, natural materials such as wood are limited in the aspect that it is us who must learn how to work with it. As the only naturally reproducible green building material, it is necessary that wood become the first choice in manufacturing and design in terms of addressing environmental concerns.4 With the rise of these virtual tools, architects and engineers are able to further their knowledge in structural systems with forms and load states that cannot easily be predicted. It is with these issues where physics-based simulations that provide real-time feedback can demonstrate their strength.5 While the traditional goal in engineering and physics is to limit the amount of bending within a structure, the goal of this study is to utilize and harness bending for the implementation of complex and lightweight designs.
Potential Application for Light and Wind
COMPUTATIONAL DESIGN
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The idea of bending-active architecture is in no way a new concept, but it is one that has not yet been fully explored. Due to the considerable challenges that come with material behaviour in the process of this specific series of design, only a few examples of bending architecture exist.6 One example of bending materials can be found with the Madan people in Southern Iraq.7 Their “Mudhif� houses are built from initially straight, reed bundles that are fixed to the ground and then connected at the tips, forming elastically bent archlike structures.8 This idea of using reed materials is not strictly limited to the middle east, as it can also be seen in multiple cultures throughout Asia, Africa and Latin America.
Example of a Mudhif House in Construction
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Example of a Mudhif House in Construction
COMPUTATIONAL DESIGN
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However, it has been translated into the modern age, where technological advances are also advancing the capabilities of knowledge about the properties of bendingactive structure and limitations. Take for example the Golden Moon installation, designed by the Laboratory for Explorative Architecture & Design Ltd. (LEAD) for the the Lantern Wonderland Design Competition in Hong Kong celebrating the 2012 Mid-Autumn Festival. The project utilized digital design technology and traditional craftsmanship in order to create complex geometry that can be built at a high speed and low cost.9 While the project utilized three primary components, it was with the secondary structure that bendingactive structures were introduced. Basing their bamboo substructure off of traditional Cantonese bamboo scaffolding designs, LEAD was able to manufacture a diagrid designed from algorithms that produce purity and repetition around the equator and imperfection and approximation at the poles.10 It was through digital computation that this was possible.
Inner Layer of the Golden Moon Installation Made from Bamboo | LEAD
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Golden Moon | LEAD | Hong Kong, 2012
COMPUTATIONAL DESIGN
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Bending-active structures can be generally divided into two main categories that relate to their geometrical dimensions and fundamental components. One-dimensional (1D) systems can be built using slender rods, such as bamboo and reeds, while two-dimensional (2D) systems use thin plates for basic building blocks.11 As per the examples relate, there is extensive knowledge and experience for 1D systems, with systems such as elastic gridshells being the most prominent application. Meanwhile, plate-dominant structures have not received as much attention, and are considered more difficult to design.12 The reason for this difficulty is due to their dimensions, which limits their bending properties in different axis. Due to these properties, plate components bend mainly along the axis of weakest inertia, preventing them from being forced into complicated-geometries. This is what makes the subset of bending-active structures interesting from a mathematical point of view, the clear scale separation, where their length is large in one dimension, and exponentially smaller in the other two.13 Having these hierarchical geometrical features is what facilitates the design process, and makes it easier to assess the structural behavior, along with accurately being able to anticipate their deformative geometry using digital simulations.14
14
3’-0”
Planned Structure of Panel
0-3”
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0-4”
Base Membrane Form
Karamba Analysis of Curvature Tension
Woven Structure Components
Membrane From Catenary Curves
Division of Base Form
In a similar aspect to synthetic composites, such as glassfibre-reinforced plastic, wood as a natural fibre composite shows a high strain at failure, otherwise meaning it has a high load-bearing capacity with relatively low stiffness.15 When designed correctly, these material properties and behaviours are well suited for construction techniques that employ the elastic bending of wood in order to form complex, lightweight, structures from simplistic, planar building elements. It is because of these properties that the design for the experimental facade panel was created. The prototype for the design began utilizing catenary curves with the development of a computational design tool, Grasshopper, which is subsequently a plug-in for the digital modeling program, Rhinoceros. By planning out the physical limitations of natural forces, the idea was that this catenary based curvature would be structured enough for the wood’s properties to handle. Through the analysis done on the properties of wood’s elasticity in terms of its linear dimensions, the width was used to determine the number of planar components that would be utilized.
Grasshopper Script
COMPUTATIONAL DESIGN
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Prototyping began with tests of form, determining how simplistic materials such as thin board would react to a woven construction. The studies showed that through this woven process, the material’s reaction to the tension forces created a stiffness and resistant strength that would create enough resistance to hold its form. Following this discovery, post division of the primary form, the planar components were translated into a 2D form in order to manufacture. The use of robotic manufacturing is a key component in the planning of these planar elements, and subsequently used for not only the initial curvature and tension, but as to form the points of connection and design in accordance to the required axis. It is through these forces that are locally stored in each bent region of the planar strips, and maintained by the corresponding tensioned region of the connecting strip that greatly increases the structural stiffness of the self-equilibrating system.16 Because of this, the manufacturing and assembly logistics were integrated into the computational design process. Upon further physical studies, the woven components, while able to take on a specific form and shape, were incapable of holding the form of the doubly-curved designed structure on their own. From this, mechanical fasteners were then introduced to hold these components to shape.
16
Initial Trial of Woven Components
Interwoven Modularity | Pun
Beginning The Process of CNC Routing Pieces
COMPUTATIONAL DESIGN
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Preparing The Routed Pieces for Fabrication
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Beginning the Fabrication Process
COMPUTATIONAL DESIGN
Beginning the Fabrication Process
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Upon implementing these fasteners, the final product was able to begin production. Upon CNC routing the necessary components, they were then sanded down and placed in the order required to create the form. The pieces were specifically cut to shape in order to create a spatial curvature, one that would allow for only the woven intersections to become planar, allowing for pre-drilled holes to match up properly. It is with these holes that the study took form. By connecting each component in specific locations, each one was able to react to the next properly and hold this shape. To fully exploit the large deformations that plywood would allow for, the thickness of the sheets of wood had to be reduced to the minimum, resulting in the radical choice of using 5.0 mm birch plywood. Since the sheets are very flexible, additional stiffness was needed to be gained by giving this geometry the shell like structure and shape that was chosen.17 The entirety of the experiment was dependent on the material properties discussed prior. Without the analysis on the stresses of the wood and its properties, it was determined that the entire project would fail or need be completely revised. The prefabrication of these components was also necessary in order to create the form.
Testing of Bending Stresses
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With the concept of modularity, prefabrication is key. Prefabrication in architecture is growing increasingly in reputation and popularity. By fabricating components and materials off site, it improves the speed of construction, quality of architecture, efficiency of materials, and worker safety, while also limiting environmental impacts of construction in comparison to site-built construction practices.18 The cladding system designed through our experimentation was designed with the idea of modularity in mind. Each panel was thought up in a way that would allow for the connection of all four corners to connect in an array. Due to this curvature, the panels could even be used for curved or cylindrical facades.
Finished Facade Panel
COMPUTATIONAL DESIGN
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Beyond the investigation of the related architectural qualities, the construction of this research project allowed for the verification of the computational design approach by comparing the digital design models and related physical geometries. The project was able to demonstrate how focusing the computational design process on material behaviour and properties rather than geometric shape was able to allow for unfolding performance capacity and material resourcefulness, while at the same time exploring previously unexplored architectural possibilities. While the study focused primarily on the use of this system as a cladding system, the uses of these bending-active structures are limitless. Whether it be for a small scale system such as ours, or a larger scale pavilion, this construct should be better utilized in the future for not only intelligent expansion, but for the benefit of green architecture.
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Rendered View of Facade Application
COMPUTATIONAL DESIGN
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References
1
Fleischmann, M., Knippers, J., Lienhard, J., Menges, A. and Schleicher, S. (2012), Material Behaviour: Embedding Physical Properties in Computational Design Processes. Archit Design, 82: 44.
2
Ibid., 45
3
Menges, Achim, ‘Pluripotent Components: An Alternative Approach to Parametric Design’, AA Files No 52, AA Publications (London), 2005, pp 64.
4
Yuan, Philip F., and Chai, Hua. “Robotic Wood Tectonics.” In Fabricate 2017, by Menges Achim, Sheil Bob, Glynn Ruairi, and Skavara Marilena, 44. London: UCL Press, 2017.
5
Schleicher, S. and La Magna (2016). Bending-active Plates: Form-finding and Form-conversion. ACADIA conference, ACADIA 2016 Posthuman Frontiers: Data, Designers and Cognitive Machines. pp 261.
6
Fleischmann, M., Knippers, J., Lienhard, J., Menges, A. and Schleicher, S. (2012), Material Behaviour: Embedding Physical Properties in Computational Design Processes. Archit Design, 82: 45.
7
Dunkelberg, Klaus, IL 31 Bambus – Bamboo, Karl Krämer Verlag (Stuttgart), 1985.
8
Oliver, Paul, Dwellings: The Vernacular House World Wide, Phaidon Press (London), 2003, p 122.
9
Crolla, Kristof. “Building Simplexity: Golden Moon, 2012 Mid-Autumn Festival Lantern Wonderland.” In Fabricate 2014: Negotiating Design & Making, by Gramazio Fabio, Kohler Matthias, and Langenberg Silke, 61. London: UCL Press, 2017.
10
Ibid. 63
11
Schleicher, S. and La Magna (2016). Bending-active Plates: Form-finding and Form-conversion. ACADIA conference, ACADIA 2016 Posthuman Frontiers: Data, Designers and Cognitive Machines. pp 261.
12
Ibid.
13
Ibid.
14
Ibid.
15
Wagenführ, André, and Scholz, Frieder, Taschenbuch der Holztechnik, Carl Hanser Verlag (Munich), 2008, p 122.
16
Fleischmann, M., Knippers, J., Lienhard, J., Menges, A. and Schleicher, S. (2012), Material Behaviour: Embedding Physical Properties in Computational Design Processes. Archit Design, 82: 47.
17
Schleicher, S. and La Magna (2016). Bending-active Plates: Form-finding and Form-conversion. ACADIA conference, ACADIA 2016 Posthuman Frontiers: Data, Designers and Cognitive Machines. pp 266.
18
Boafo, Fred, Jin-Hee Kim, and Jun-Tae Kim. “Performance of Modular Prefabricated Architecture.” MDPI. June 15, 2016.
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Acknowledgement
The author would like to thank Alexandra Noll, with whom was a partner in this theoretical project, along with the supervision of professor Kihong Ku. Without their assistance, this project would not have been a success.
COMPUTATIONAL DESIGN
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