C journal by Cedric Chua

STUDIO AIR JOURNAL

CEDRIC CHUA 835148

STUDIO 2 ALESSANDRO LIUTI

2018 S1 1

Introduction

Part A - Conceptualisation

A1 - Design Futuring

6 12 18

A2 - Design Computation

A4 - Design Approach

A5 - Learning Outcomes

A6 - Algorithmic Sketches

A3 - Composition/Generation

Part B - Criteria Design

B1 - On Shell Structures

B2 - Case Study 1.0

B3 - Case Study 2.0

B4 - Technique: Development

B5 - Prototyping

B6 - Design Proposal

B7 - Feedback

B8 - Algorithmic Sketches

Part C - Detailed Design

C1 - Design Concept

Algorithmic Process - Limitations - Design Proposal - Drawings - Construction Sequence

C2 - Prototyping Constructability - Materiality

C3 - Reflection

86 94

Introduction

My name is Cedric Chua. I am a third-year architecture student from the University of Melbourne. My second year of education has provided me with opportunities to obtain a diligent attitude towards my personal design process. I also gained a general understanding towards the many different layers of design and values that make up architecture, mostly focused on pragmatic and aesthetic concerns. One of the challenges that I think Studio Air brings me is the implementation of digital theories into my design process. I have seen both student and professional works that focus on complex digital forms and while most of them are pleasing to look at, I often find myself puzzled by the theoretical agenda behind them and the vague and ambiguous values they bring to a design. One of my goals for this subject is to unpack and understand the value that

this movement of â&#x20AC;&#x2DC;parametric designâ&#x20AC;&#x2122; brings to architecture in particular. As of now, I understand the value of parametric software as useful tools in optimising and speeding up the design of a building. Beyond pragmatic use-cases, I have yet to discover a convincing argument of the use of parametric tools, and I hope to shed light on that matter. On a more technical note, I have a decent amount of experience in Rhino3D and understanding of the benefits of nurbsbased modelling. I have never used Grasshopper prior to this subject and I aim to familiarise myself with its commands and the workflow of algorithmic design. I have some experience in architectural visualisation and I am confident in using the Adobe Suite programs.

Top: Studio Water work Bottom: Digital Design & Fabrication work

A.1 Design Futuring

2016/17 ICD/ITKE Pavilion

Case Study 1 ICD/ITKE 2016/17 Pavilion

In 2010, the Institute of Computation and Design collaborated with the Institute of Building Structures and Structural Design to begin an annual research project on highly innovative lightweight structures using stateof-the-art technology (CNC-guided robotic construction). All its projects since 2011 have had an intense focus on biomimicry as the driver for the pavilion’s formal qualities and fabrication process. The contribution of a biomimetic design approach lies in the unique solutions that nature provides. The transfer of knowledge from the scientific domain into the architectural/engineering domain has the potential to uncover new engineering systems that are more efficient than existing ones. This links well to Anthony Dunne’s book, ‘Speculative Everything’. Dunne asserts that designers should push towards imagining new and possible solutions, to open up new perspectives and dare to alter current values of an established system 1. This is essentially what the research project is trying to achieve; the collaboration of engineers and biologists to use biomimicry as an approach to discover new and unexpected outcomes, and to use these findings as a base to further discuss possible innovations to the future of the construction and architectural industry. To illustrate this process, 2016/17 ICD/ ITKE Pavilion begins its design through the research of construction principles in natural long span composite structures (leaf miner moths) with the goal to develop a scalable fabrication process that utilises tensile forces to produce long span fibre structures made with lightweight materials 2. It resulted in an

impressive twelve metre cantilever structure made with 184km of glass and carbon fibre. The pavilion raises questions about how such a design and construction method may be used for architectural applications.

Figure 1: ICD Pavilion 2017 (img © Roland Halbe)

However, the goals of this research program are still speculative at this point. I have yet to see any real-world applications from the design of these pavilions. The design methodology is highly complex and requires highly trained people to operate and construct. I believe they should tone down the complexity of their projects if they are truly aiming to provide real world applications(or perhaps they are hoping that others will further develop on their research findings). Another critique I have is that their research is that they are experimenting through designing pavilions (functionless/ temporary structures that add a temporary bling to a space); they don’t provide a solid foundation to build up values on. It would make more sense if they changed their brief into the design of more practical applications such as building facades, structural systems, etc. Nevertheless, their works are very wellresearched and pushes the boundaries of design and construction technology.

Anthony Dunne and Fiona Raby, Speculative Everything: Design Fiction, and Social Dreaming (Cambridge, MIT Press, 2013) pp. 6. 2 Institute for Computational Design and Construction & Institute of Building Structures and Structural Design, ICD/ITKE Research Pavilion 2016-17 (2017), http://icd.unistuttgart.de/?p=18905 9

Case Study 2 British Museum Great Court Foster + Partners, London, UK (2000)

The focus of Studio #2 is on the study and design of lightweight structures. The Great Court Museum is a good precedent regarding the topic of grid shell structures, which is one type of lightweight structure. I do not think of the technology behind this project as revolutionary, I’d rather consider the design of the glass roof as part of the wider movement/trend of large-scale projects that implemented complex free-form structures to cover a significantly large floor area. A very important step in the design of such large scale structural forms is the optimisation of its overall form concerning structural and environmental factors.

not easily accessible. The Great Court has received positive reception since then. This goes to show that the public does find value in elegantly designed curved structures, not to be confused with inefficient ‘Blobitectural’ forms. This sets an excellent precedent in the category of gridshell structures. The main lessons to be taken from this is that formal innovation is made possible through parametric and computational resources. These lightweight forms have the potential to add a distinctive identity to an urban space. However, it requires a large, highly qualified and experienced team to execute a project of such scale and complexity.

Figure 2: The Great Court in the British Museum (img © Foster + Partners)

The form of the glazed roof in this project is unique. The shape of the surface is resolved first. It is determined by the rectangular and circular boundaries (site-specific constraints) and the curvature of the surface in the rectangular corners was made possible by a mathematical concept called ‘singularity’. The next step was the generation of steel members and glass dimensions and this was solved through mesh subdivision. The designers specifically used triangular faces to produce the most efficient structure 3. Using parametric software, the vertices of the surface could be adjusted and optimised. The project was completed in 2000, during a time when parametric software was 3

Jane Burry and Mark Burry, The New Mathematics of Architecture (United Kingdom, Thames & Hudson Ltd, 2012), pp. 123-125.

A.2 Design Computation

In the past two decades, there has been an undeniable shift towards the use of computation in architectural design. The reason is simple; computational tools significantly speed up the design process of buildings and structures. These software tools have been extensively developed and have become widely accessible on a global scale. These benefits outperform the use of traditional tools in todayâ&#x20AC;&#x2122;s dynamic world, where most information have become digitised. It is now a necessity to adapt to new and developing technologies, or we risk being left behind. With a focus on architectural and structural design, the influence of these computational tools lies in their ability to produce unique topological forms, whether the product is a faĂ§ade, structural system, concept, etc. According to Oxman, there is a movement towards the use of parametric tools to design forms that responds to environmental factors. Using algorithms and scripting, designers and engineers can develop a new discipline of form-finding and optimisation techniques that combine design and construction. Over the past two decades, there have been many architectural projects that implement parametric design processes to articulate building forms and this confirms that there is a distinct trend here. The two following case studies will explore how far technology has advanced, particularly in the context of lightweight structures.

Case Study 3 Palazzetto della Sport Pier Luigi Nervi (1960)

Nervi was a renowned engineer during the 20th century. He was known for valuing the aesthetical side of structural design and his stadium design, Palazzetto della Sport, is a testament to his design philosophy. The building features a concrete domed roof that transfers its compressive loads from the interlaced ribs onto exterior Y-shaped buttresses. The project was designed and built without the use of computational tools and I will briefly elaborate on the disadvantage that Nervi was put on in the absence of these tools.

lightweight structures. But his efforts do not hold a candle to the power of computation tools when it comes to formal and structural innovation.

Figure 3: The dome of Palazzetto della Sport (img © Maria Teresa Cutrì) Figure 4: Sectional drawing of the stadium (img © Maria Teresa Cutrì)

The design process of a lightweight structure is far more time consuming compared to when a digital approach is used. Nervi had to iterate and realise the dome structure through the study of physical models and generating geodetic frameworks through them 4. Not only was the process extremely demanding but has also limited Nervi to design symmetrical forms in order that it may be structurally stable. Furthermore, the formal qualities must conform to the structural capabilities of reinforced concrete (although Nervi made it work quite well). The lack of computational tools has forced the constraints of manual and time-consuming calculations onto the design of lightweight structures. Nervi, at the time, was already pushing the boundaries of what could be done with reinforced concrete and

Ada Louise Huxtable, Pier Luigi Nervi (New York, George Braziller Inc., 1960), p.p. 24.

Case Study 4 kakamigahara crematorium Toyo Ito (2006)

Ito’s Kakamigahara Crematorium also uses reinforced concrete as the material for the roof structure. Compared to the Palazzetto della Sport, the crematorium is much more free-form in nature. Through parametric software, Ito was able to guide the design process in a way that the conceptual and formal qualities of the building could be intensively explored without compromising its structural stability. The design process aligns with Oxman’s narrative of the shift towards the generation of topological forms using algorithmic/parametric processes 5. Ito optimised the form of the roof by setting specific parameters through a technique called sensitivity analysis 6 and as a result, the roof appears as a continuous surface and successfully realising his initial concept of suggesting the form of rolling hills. This kind of formal innovation could never be achieved without computation tools.

Figure 5: The dome of Palazzetto della Sport (img © Toyo Ito & Associates, Architects)

Oxman, p.p. 3-4. Shells for Architecture, ed. by Sigrid Adriaenssens, Philippe Block, Diederik Veenendaal and Chris Williams (New York, Routledge, 2014), p. 226. 6

A.3 Composition/generation

The topic of focus in this section is on algorithms. The term algorithm can be interpreted and used in different ways, whether it is mathematically-based or rule-based and physically generated or computationally generated. For the purposes of this studio’s goals, the definition of an algorithm will follow that of ‘The MIT Encyclopedia of the Cognitive Sciences.’ The writers propose an algorithm as a finite set of unambiguous and precise list of simple operations. These operations/functions must be set with clear intentions and generated through computational means7. The key here is to use simple and well-informed rules to generate complex forms. One of the main methods of integrating algorithms into the architectural design process is through the process of optimisation. Optimisation can be controlled to address specific issues such as structural analysis, response to sunlight, conceptual development, etc. The use of algorithms in architectural practice has given architects the opportunity to integrate constructional methods to the formal qualities of a structure, thereby opening up opportunities to innovate and expand the domain of the architectural field. However, designers should also stay aware of their personal design goals and understand the potential consequences of using algorithms in their design process. As Hugh Whitehead argues: “There is the danger that if the celebration of [algorithmic design] can obscure and divert from the real design objectives, then scripting degenerates to become an isolated craft rather than developing into an integrated art form.”8

Robert A. and Frank C, The MIT Encyclopedia of the Cognitive Sciences (London: MIT Press, 1999), p. 11. 8 Brady Peters, ‘Computation Works: The Building Algorithmic Thought’, Architectural Design, 83, 2, (2013), 08-15 (p.15).

Case Study 5 Mannheim Multihalle Calfried Mutschler + Frei Otto (1975)

This is a project from 1975 that utilised the process of Ottoâ&#x20AC;&#x2122;s reverse hanging method to generate the compressive gridshell form. The result was a large spanning timber lightweight gridshell. As mentioned in part A2, the process of using physical testing and iterations is extremely time-consuming and is poor when it is compared to the performance of computational/algorithmic tools. The formal realisation was also limited to modular quadrilateral 0.5m units9. There really isnâ&#x20AC;&#x2122;t anything to contest when comparing physical testing to computational generation.

Figure 6: The interior of the Multihalle (photo ÂŠ Daniel Lukac)

Adriaenssens, pp. 241.

Case Study 5 NEST-Hilo unit BRG and Chair of Architecture and Building Systems (ETH Zurich) (2017)

This is an interesting research program that utilises a concrete shell structure to address environmental issues and is the most convincing use case of a shell structure I have come across so far. The project utilised algorithmic processes to generate a shell form that simultaneously confronts the issues of material efficiency, spatial/formal quality, energy usage, cost of construction and so on. The thin concrete shell is coupled with polyurethane foam insulation and photovoltaic cells are installed on the upper surface to generate solar energy. Thermal issues are also addressed by integrating conventional construction methods to the shell structure.10 This project is an illustration of how design and engineer can push the boundaries of a building typology to increase its value, combining innovative formal design with environmental concerns creates a strong case study that can potentially challenge the existing constructional conventions, given enough time for optimisation and simplification so that mass adoption becomes an option. This is where Jorg Schlaich’s argument for the social advantages of lightweight structures11 becomes relevant, this kind of innovation, assuming that its construction becomes economically and environmentally viable, will create a niche of algorithmic designers and jobs. With the adoption of appropriate

values, unconventional methods have the potential to become the norm.

Figure 7: Construction of the HiLo shell (photo © Michael Lyrenmann) Figure 8: Sectional Diagram of the HiLo shell (img © Philippe Block)

Philippe Block, ‘Parametricism Structural Congeniality’, Architectural Design, 86, 2, (2013), 68-75 (p.75). 11 Jörg Schlaich and Mike Schlaich, Lightweight Structures.

A.4 Design Approach

Having gone through the readings, I have realised the need to develop a fundamental understanding of lightweight structures regarding formal/conceptual development, algorithmic generation of efficient forms and the process of optimisation to achieve said form. I have decided to focus my attention onto shell structures with concrete as the building material. My goal is to develop a concept where concrete shells are designed to align with the design goals of the new student precinct.

A.5 Learning Outcomes

Firstly, the idea of speculative thinking was introduced, which is the idea that designers should actively think about ways to expand the boundaries of a particular field (I think, in which innovation can vary in different scales e.g. Between a large scale conceptual innovation to small scale changes in existing designs) In this studioâ&#x20AC;&#x2122;s case, there should be an emphasis on speculating how the design of a lightweight structure can be enhanced to adapt to additional features. Issues such as the long-term life span of the design and potential consequences should also be carefully considered. In both parts A2 and A3, we were prompted to write about the significance of computational power in the architectural design process. Its benefits are obvious; fast computing performances can be used to optimise the design process and conceptual development. At the same time, we need to control these algorithms as a tool, rather than an automated design generator.

A.6 Algorithmic Sketches

Surface Lofting

Gradient Projection onto Mesh

Frame Generated from Geodetic Curves on Surface

Kangaroo-Generated Forms

Part B Criteria design

“ Shell structures can be geometrically represented by surfaces. Shells are relatively rigid.

”

Shells work through a combination of membrane and bending action. Chris Williams - ‘Shell Structures for Architecture’ 12

B1 On Shell Structures

One’s first impression of what a shell is likely to relate to a 3D fully curved solid that encapsulates something. Indeed, there are many interpretations of what a shell could be. The definition of a shell structure in this studio is tied to lightweight structural principles, specifically a materially efficient(thin) and continuous(rigid) surface that works under pure compression. These characteristics gives shell structures the benefit of achieving a relatively low construction costs, lower material inefficiency (and also neatness as a result), fire-resistance, easily available materials and energy efficiency. Working from these fundamental principles, it is also possible to alter the shell’s formal qualities using parametric software tools. It is also important to note the history behind shell structures and why it has declined in popularity. Their construction came to life during the early 20th century due to the pioneering works of figures like Heinz Isler, Felix Candela and so on. Between 1920 to 1960, these designers have exhaustively experimented with shell structures, each building up a portfolio of impressive shell forms.13 Shell structures have seen a decline in construction ever since due to multiple factors, including difficult construction, a need for specialised builders and low demand. One valid point is that shell structures are rigid and are not able to adapt to the requirements of certain building typologies that require flexible components. These factors essentially show that shell structures are outperformed by alternative structural systems, but only in specific contexts. Another reason for its

decline is an external factor; that shells are simply “not architecturally in vogue.” There is the consensus that concrete/masonry shells are conceived as brutal, dense and out-dated.14 However, this notion is rather subjective and can be argued against through elegantly designed shells that functions well in a particular context. It seems that the designing of shell structures has been neglected due to ignorance and the laziness to explore the different spaces that a shell structure can successfully accommodate. With the emergence of parametric software, the design and formal realisation of shell structures become much easier and significantly speeds up its design and construction process. Designers can now use parametric tools to quickly estimate the structural stability of shell structures. Furthermore, they are also able to move structural concerns down in the list of priorities and focus on conceptual/formal qualities of the shell structure, providing new opportunities to conceive aesthetically and elegantly designed shell structures. New technology allows the formwork of the shell structures to be prefabricated and assembled onsite with precision and order. New technology creates a respectable case for the use of shell structures that should not be overlooked. Chris Williams, Shells for Architecture, p. 21-26. Christian M and Michael H.S, ‘Do Concrete Shells Deserve Another Look?’, Concrete International, 10 (2005), 43-50 (p.43). 14 Christian, p.47. 12

B2: Case study 1.0 Bp Service Station Heinz Isler (1968)

Heinz Isler was one of the earliest adopters of concrete shell structures. The BP Service Station is one of his many projects and its form was designed using the reversehanging membrane technique. This is a good shell structure precedent to study from because it has an extremely basic form. Through the generation of the form in grasshopper, it is possible to understand the main parameters that are needed to design a shell form. These fundamental parameters can be further developed to generate more complex forms. The parametric design process requires being able to look at problems from difference perspectives. According to Woodbury, parametric designers require the ability to organise a continuous algorithm through abstract, mathematical and algorithmic points of view. On top of that skillset, parametric designers are also able to form a personal and organic design process that allows them to propose unique formal qualities through flexible workflows15. These design tactics include the ability to modify and reuse codes (specific to design concerns) and to defer site constraint issues. The following case study allows me to deconstruct the algorithm of a basic shell form and decide on the hierarchy of its components. These components can then be individually altered to achieve specific

form and conformation to site constraints. The mathematical concepts behind the curvature of the shell surface should also be considered.

Figure 9: View of BP Service Station (photo ÂŠ Chriusha)

Theories in Digital Architecture, ed. by Rivka Oxman and Robert Oxman (London; New York: Routledge, 2014), p. 155-169.

12 variations of the BP service station Algorithm

Base Geometry: Triangle (Original Form) No. of anchor points: 3 (2 pts projected 3.5 units up) Load factor: 0.122 Line strength: 30 SC strength: 3.00

Base Geometry: Triangle (Original Form) No. of anchor points: 3 Load factor: 0.122 Line strength: 30 SC strength: 0.00

Base Geometry: Triangle (Original Form) No. of anchor points: 3 Load factor: 0.122 Line strength: 30 SC strength: 10.00

Base Geometry: Square No. of anchor points: 4 Load factor: 0.122 Line strength: 30 SC strength: 1.0

Base Geometry: Hexagonal plane No. of anchor points: 6 Load factor: 0.500 Line strength: 30 SC strength: 1.0

Base Geometry: L-shaped plane No. of anchor points: 6 Load factor: 0.122 Line strength: 50 SC strength: 1.0

Base Geometry: Rectanglular Plane No. of anchor points: 4 Load factor: 0.122 Line strength: 20 SC strength: 1.0

Base Geometry: Triangle with curved edges No. of anchor points: 3 Load factor: 0.122 Line strength: 60 SC strength: 1.0

Base Geometry: Sqaure with oculus No. of anchor points: 4 Load factor: 0.500 Line strength: 30 SC strength: 1.0

Base Geometry: Square with oculus No. of anchor points: 11 Load factor: 0.122 Line strength: 30 SC strength: 1.0

Base Geometry: Square with 4 oculus No. of anchor points: 32 Load factor: 0.122 Line strength: 30 SC strength: 1.0

Base Geometry: Trapezium No. of anchor points: 44 Load factor: 0.122 Line strength: 30 SC strength: 1.0

Successful Variations

5 These 4 variations were chosen as â&#x20AC;&#x2DC;successfulâ&#x20AC;&#x2122; iterations for 2 similar reasons:

1. Structural Stability All variations have an optimally form-found structure (with the exception of variation no.9) that works in pure compression. 2. Spannable Area All 4 variations can be scaled to cover any desired amount of area, in which any program can be accomodated.

All variations have differing levels of light admission, with variation no.4 have the least amount. However, an oculus can be implemented to admit light into the interior space, as shown by variation no.9. One major limitation with this particular algorithm is that the reverse-hanging form finding technique greatly decreases the potential for complex forms; the method enslaves the designer to catenary forms.

9 43

B3: Case study 2.0 Armadillo Vault Block Research Group (2016)

The Armadillo Vault was a project that aimed to revisit the lost art of masonry vault construction and to enhance its design and construction through complex computational geometries and digital fabrication16. There was a balance between combining traditional masonry construction techniques with computational tools. For instance, the design team utilised the Thrust Network Analysis (TNA) to realise the form of the vault, which is a similar method that can be traditionally used to find funicular shapes. The unique aspect of the project comes in the individually unique geometries of the voussoirs, which could not be calculated without computation. Through old ways of thinking and new ways of conceptualisation, BRG was able to successfully produce the Armadillo Vault, which is structurally efficient and stable while expressing the process of masonry vault construction. The result of the project was a doubly curved vault with 399 unique voussoirs that are constructed through a staggered arrangement. No mortars were used and the structure is under pure compression. The ground supports, however, were designed to react against the horizontal thrust of the vault using steel ties under tension. Through computational tools, the thickness of each voussoir was optimised and reduced to

a minimum value, in which any smaller thickness would lead to structural failure17. To produce the thicknesses, the internal side of the voussoirs had to be cut. The design team implemented an interesting solution which produced ‘rough cuts.’ Despite its tessellated nature, the internal wall of the vault produces a ‘smooth’ pattern of rough edges as though it was a continuous surface. It is a unique way of producing patterns/ornamentation. As Branko Kolarevic would contend, this pattern creates psychological ‘affects’ that contribute to the wider architectural discourse18. The ‘affects’ that it may trigger are subject to different interpretations, but nevertheless engages visitors with thoughts about architectural expression and construction.

Figure 10: View of BP Armadillo Vault (photo © BRG)

Rippmann M., Van Mele T., Popescu M., Augustynowicz E., Méndez Echenagucia T., Calvo Barentin C., Frick U. and Block P. ‘The Armadillo Vault: Computational design and digital fabrication of a freeform stone shell,’ Advances in Architectural Geometry 2016,: 344-363 (p.348) 17 Rippmann, p. 350 18 Kolarevic, Branko and Kevin R. Klinger, Manufacturing Material Effects: Rethinking Design and Making in Architecture (New York; London: Routledge,2008), p. 6

Reverse Engineering Process

Form-Finding Using the RhinoVault plugin to generate form using TNA. 1 – Generation of dual diagram from form edges. 2 – Adjusting node strengths and form relaxation. 3 – Finding horizontal and vertical equilibrium.

Tessellation Using a grasshopper definition consisting of MeshMachine, PlanktonMesh and Weaverbird extensions. Major parameters: 1 – MeshMachine Edge Length 2 – WeaverBird Dual + Weaverbird Tile

Voussoir Geometry Weaverbird Mesh Thicken component to control the thickness of each voussoir. The thickness can be varied using a point/curve attractor.

B4: Technique Development 10 iterations focusing on the formal composition of the vault. Vaults vary in the number of supports, openings and open/arced edges

1. Original Mesh

2. ‘3 sided’ Vault

3. ‘4 sided

No. of supports: 3 No. of openings: 2 No. of arced edges: 3

No. of supports: 3 No. of openings: 3 No. of arced edges: 3

No. of supp No. of open No. of arced

6. Dome Vault

7. U-shaped Vault

8. Dome

No. of supports: 1 continuous curve No. of openings: 2 No. of arced edges: 1

No. of supports: 4 No. of openings: 0 No. of arced edges: 4

No. of supports: 1 c No. of open No. of arced

d’ Vault

4. ‘4 sided’ Vault with oculus

5. ‘4 sided’ Vault wiht thrust lines on edge

ports: 4 nings: 0 edges: 4

No. of supports: 4 No. of openings: 1 No. of arced edges: 4

No. of supports: 4 No. of openings: 0 No. of arced edges: 4

Vault

9. Dome Vault

10. Assymetrical Vault

No. of supports: 1 continous curve No. of openings: 4 No. of arced edges: 1

No. of supports: 6 No. of openings: 2 No. of arced edges: 6

continous curve nings: 1 edges: 0

B4: Technique Development 5 iterations focusing on tessellation methods and 5 iterations focusing on voussoir generation.

11. Tracing + Projection onto Mesh

12. Tracing on Vault Edges

Inaccurate + Failure to produce planar faces.

Not all edges connect.

16. Thickness value: 0.5

13. Approximating a NU box

Inaccurate Tessellations do not trans polysurfa

17. Thickness value: 1.0

18. Thickness

URBS Vault + Luncx

e form + slate between different aces.

s Value: 3.5

14. MeshMachine + Weaverbird

15. MeshMachine + Weaverbird

Edge Length set to 0.1, producing dense tessellations.

Edge length set to 1.0

19. Thickness Value(s): 0.1 (min) + 3.5 (max)

20. Thickness Value(s): 0.1 (min) + 3.5 (max)

Point attractor is used to make the voussoirs thicker on the outer edges and thinner near the middle.

Process is reversed. (Thicker in middle and thinner around the edges)

B4: Successful Iterations + Selection Criteria Iteration 10 The ‘Asymmetrical Vault’ was chosen as a successful iteration for the following reasons:

Porosity As my group’s current design proposal is an informal outdoor study space, the level of light admission is a major part of the design process. This iteration admits a good amount of light through the open edges and the oculus openings admit light into the darkest regions of the vault.

Formal Quality The formal composition offers a more fluid and dynamic ‘affect’. With all sides open to access, the structure allows for a lot of transparency both from the inside and outside. Part of the ‘oculus’ openings can also be anchored to the ground to create different zones within the vault.

Iteration 19 The use of attractors to control the mesh thickness is one possible way to control the process of structural optimisation. (eg. voussoirs can be made thin in areas where the voussoirs are laid on a relatively flat angle, vice versa) However, there are limits to the grasshopper definition used to generate the meshes. The edges of the vault are not smoothed out. Additionally, if the mesh is thickened after its faces are exploded, the extrusion angle does not allow for the contact faces between each voussoir to precisely meet each other.

B.5 Prototyping

2 categories of prototypes were produced; cast concrete to emulate sensoral effects and 3D printed voussoirs to emulate the construction process. The goal of the concrete cast prototypes were to emulate the effects of translucent concrete, otherwise known as Litracon as developed by Aron Losonczi. The key parameters are as follows: i - Cement to water ratio ii - Thickness of plastic strings/rods iii - Length and amount of glassfibre reinforcement iv - Formwork

Prototype 1 Cement to water to sand ratio: 5:4:2 Thickness of plastic strings: 1mm Glassfibre reinforcement: Pulled glassfibre strands Formwork: Plywood cuboid with foam base

Prototype 2 Cement to water ratio: 5:2 Thickness of plastic strings:

<1mm

Glassfibre reinforcement: Pulled and cut glassfibre strands Formwork: Plastic Container

Prototype 3 Cement to water ratio: 2:1 Thickness of plastic strings:

1.5mm

Glassfibre reinforcement: Pulled and cut glassfibre strands Formwork: Plastic Container

B5: Cast concrete prototyping

Findings: - Legible amount of light admitted through thicker plastic rods. - High workability.

Overall conclusions: Due to the limited time frame our group had, we had to resort to using poor formwork material as well as cheap and available plastic strings for light admittance. However, we established that the use of plastic strands can definitely admit light to produce a desire effect and that different mixes of concrete can be used to cast the voussoirs. In the coming weeks, these are areas we need to further develop regarding our cast concrete prototypes: 1 - Development of proper formwork The current plan is to solve the voussoir geometries and be able to transfer the data into a 3-axis CNC mill for foam subtraction. 2 - Achieving a smooth finish A suitable coating needs to be used to ensure the surfaces of the cut foam can produce a smooth surface. 3 - Understanding and finding an appropriate cement to water mix Implications of different water to cement ratios need to be understood and justified. This includes things like concrete strength, durability, etc. 4 - Type of transparent rod material Alternatives to cheap plastic strings are to be explored. Options open to exploration at the moment are pexiglass rods and optical fibre strands. 5 - Patterning and density of porosity/translucency in concrete panel. Grasshopper to be used to adjust a range of different densities of transparent units to be incorporated into each voussoir. A laser cut board is also to be used as a guide for insertion of these units. This is to be developed with the overall form/design of the shell.

B5: Constructability prototyping

In order to emulate the construction process of the voussoir based shell structure, a simplified shell with 3 support points was used to understand the process of digital modelling and converting the geometries into reality via 3D printing. The position of the support point is precisely located through laser cutting the base plate. The waffle sectioned formwork is roughly placed in the right position. Voussoirs are then stacked one by one.

Limitations The contact faces between each voussoir is slippery. Even though every contact faces fit into each other, there is insufficient force keeping them in the right position. In a life-size model of the shell, some kind of friction or shear resisting surface needs to be implemented to prevent the voussoirs from falling and creating local structural failures. This poses a huge safety risk. On top of that, the 3d printed voussoirs are extremely light and asserts only a small amount of horizontal thrust towards the other

voussoirs. The smaller voussoirs must be glued to other pieces to form larger pieces with a higher weight in order for the model to be assembled smoothly. The grasshopper definition needs to be refined to generate larger voussoir pieces in the coming weeks. Some of the voussoirs near the edges become structurally redundant. In order to maintain a smooth edge, some kind of joint must be implemented to support these pieces.

Proposed Area

Relation to other outdoor spaces

Preserved Trees

Circulation paths

B6: Design proposal

Through our site analysis, we identified that the 1888 garden area is an underdesigned part of the New Student Precinct project. The region is relatively quiet with no comfortable outdoor facilities for use. Therefore, our group is proposing to locate our shell structure design on this site as a means to enrich the quality of the outdoor space, drawing more attention and use to the area. We agreed that the structure should be used as an informal study and meeting space. Our conceptual design proposal consists of two main design factors. The first is primarily involved with pragmatic concerns; the area and span to be used. We decided to allocate 50% of the structure for use as table spaces and the other half as open space for casual gatherings. The second design factor is the creation of sensoral effects through the tranclusent concrete materiality. Through parametric software, we will be able to create a gradient of different levels of porosity across the entire shell structure. Essentially, we are taking a lightweight shell structure and enhancing its design through the ornamental materiality.

Site context

A 62

Plan

Front Elevation

Section AA

B7: Feedback

I thought the most outstanding feedback came from the critâ&#x20AC;&#x2122;s positive reaction to the materiality we are proposing. It became clear to me that it is an aspect of the design that needs to be intensively developed and refined in order for the project to really succeed. From this, I also realised, if our focus shifts towards the patterning of the concreteâ&#x20AC;&#x2122;s porosity, that our proposed program of and informal study space is not optimal. I believe that a more suitable program is possible, and we will work towards deciding that. After the establishment of the program, the form also has to refined to fit both the function and how the sensoral effects are perceived. Specifically, one particular feedback about our formal execution was that it could be further enclosed to amplify the effects of light admittance. Other aspects of the formal interpretation of our shell structure that can be further developed includes the introduction of different ground levels, inclusion of oculus and different ceiling heights. There is also the possibility of pushing the design to span over a large area. The final aspect that has to be worked on is the structural optimisation of the voussoirs, in regards to varying thicknesses throughout the shell and the support structures at the anchor points.

B.8 Algorithmic Sketches

Part c Detailed Design

C1.0 The Armadillo Vault as a Precedent The Armadillo Vault by the BRG was an ambitious project that was made possible through extremely precise fabrication and construction processes. Its most significant feature is the use of 399 discretised limestone voussoirs that were built without the use of any reinforcement or connective agents. The strengths of the design lie in its unique form and structure; pushing the boundaries of structurally efficient shell structures with a high span to thickness ratio through prefabricated components. However, compromises have to be made to achieve these features, including risk of collapsing due to localised structural failures, material wastage (in which the falseworks are not reusable due to its discretised nature) and an extremely rigorous design process to achieve structural optimisation. Due to these shortcomings, I believe that the design creates more problems than it solves them in regards to designing viable structures that can be adopted in other situations. However, the fact that the structure was actually constructed is a marvel in itself. It shows that structural efficiency of shell structures can indeed be pushed to its limits, and that opens up new possibilities for an increase in the approval of shell structures as an option for architectural design in the future.

That being said, this project is an examination of the design process behind the Armadillo Vault and an attempt to replicate it in our groupâ&#x20AC;&#x2122;s shell structure. That was the original intent, but we were not able to implement their methodology beyond the use of TNA for the form finding technique. The process that we used for the generation of tessellations and voussoir geometries relied on simple grasshopper definitions, whereas the BRG utilised physics-based theories in realising their tessellations (which were all parallel to the shellâ&#x20AC;&#x2122;s local force lines), localised voussoir thicknesses, automated iterations to ensure planarity of contact faces, doubly-curved internal surface (all resulting in 4 distinct axes to account for in each voussoir) and a rigorous structural optimisation processes that involved both digital and physical testing. The design process of the Armadillo Vault is far more rigorous compared to what we were able to accomplish in the limited timeframe and experience that we had. The following pages will outline the issues that we were able to identify and address.

C1.1 The Algorithmic Process

1. Structural Equilibrium is achieved using the TNA

2. Remeshing to produce triangulated tessellations

3. Duals of triangles are used to produce hexagonal tessellations

4. Planarization via Kangaroo

5. Planarized Mesh is offset at variable distances and lofted

6. Voussoir geometries are produced via capping

C1.2 Limitations of the algorithm

GENERATION OF CREASE LINES Kangaroo provides very little control over the outcome of the planarized tessellations. The main parameter that can be controlled is the maximum and minimum lengths of the tessellation edges, which needs to be constrained in order to produce smoother tessellations. Multiple attempts were made to create a shell structure with an oculus. However, the planarization processes always generates crease lines near the opening which will lead to irregular load distribution in the voussoirs, leading to a high chance of local structural failure. While these crease lines can be eliminated by further restricting the edge lengths, it causes the tessellations around the oculus to warp and disrupts the offsetting process. The tessellations must be optimised through computational optimisation processes in order to make more complex shell forms possible.

LIMITED CONTROL OVER TESSELLATION DENSITY The only way to control the density of the tessellations is through carefully planning out the mesh spacings in RhinoVault. This is also the reason why we could not generate viable tessellations for an â&#x20AC;&#x2DC;internalâ&#x20AC;&#x2122; support for our shell structure the way it was done in the centre of the Armadillo Vault; a sufficient amount of mesh faces must be provided to generate a smooth mesh for the internal support, resulting in dense tessellations with inefficient lengths.

JAGGED NAKED EDGES Another limitation of the using these grasshopper components to generate the tessellations is that there is almost no control in smoothing out the edges of the shell structure. In most of our iterations, the edges of the shell were rough and jaggered.

SIMPLIFYING THE FORM For these reasons, we had to settle with a very simple form for our shell structure in order to produce regular tessellations, smooth edges and to generate voussoir geometries that do not involve geometrical issues that require complex optimisation processes.

C1.3 The Design Proposal Architecturally speaking, the aim of the design is to bring more activity to the 1888 garden area. We intend the shell structure to act as a public landmark that instils curiosity in passer-byâ&#x20AC;&#x2122;s and draws them to use the space. On top of the lightweight form of the shell structure, one significant aspect of our design that will create this attraction is through the material properties of the voussoirs. We have decided to explore 76

the use of concrete cast voussoirs with integrated acrylic rods that allow light to pass through them. The density of rods in each voussoir shall be referred to as a â&#x20AC;&#x2DC;porosityâ&#x20AC;&#x2122; level for this project. 4 porosity values are used through the shell; 1.5%, 1.0%, 0.5% and 0.0% (percentage of the area of each voussoir). They are set so that the porosity is highest at the centre, and decreases as it approaches the supports, creating a gradient from

porous to opaque. As an alternative to the use of limestones with a rough texture as done in the Armadillo Vault, we were able to integrate a feeling of transparency into the lightweight shell. The porosity values are also linked to the thickness values as shown in C1.4 in order to introduce a standardised fabrication process for the voussoirs.

C1.4 Drawings

Gra nt Str e

Site Context

Gra nt Str e

Proposed Design

Plan

10 m

Section

10 m 79

C1.5 Detail Drawings

100mm thickness | 0.0% Porosity 80mm thickness | 0.5% Porosity 60mm thickness | 1.0% Porosity 50mm thickness | 1.5% Porosity

Metal Plate Supports Tiling Tension Ties Anchored Connection Pad Footing

500mm

Footing Detail

Mortar Connection between Voussoirs

Layout of Tension Ties

C1.6 Construction sequence

1. Fabrication of Voussoirs

4. Falsework Prop-up

2. Excavation, Levelling and

5. Voussoirs are placed

d Pad Footing Construction

and joined with mortar

3. Installation of Metal Base Support and Tension Ties

6. Decentring of Falsework after all Voussoirs are placed

C2 Tectonic Elements & Prototypes

C2.1 materiality of voussoirs The shell structure is comprised of 190 unique voussoirs. Our group made 5 cast concrete prototypes, each with a unique set of dimensions extracted from the 3D model. Following the concrete prototypes from Part B, we produced these prototypes with a focus on the type of formwork, surface finishing and type of rod. The concrete mix was constant for all voussoirs at a ratio of 6:1:2 (white cement : sand : water); in which the main concern was that it needed to be workable enough to be able to flow through the acrylic rods.

Rod Diameter: 3.0 mm Formwork Type: CNC-Milled Foam Surface Finish: Taping Porosity Value: 2.0%

Rod Diameter: 3.0 mm Formwork Type: Laser-Cut MDF Surface Finish: Plastic Drop Sheet Porosity Value: 2.0% 86

Rod Diameter: 6.0 mm Formwork Type: Laser-Cut MDF Surface Finish: Polypropylene Sheet Porosity Value: 1.5%

Rod Diameter: 3.0 mm Formwork Type: Laser-Cut MDF Surface Finish: Plastic Drop Sheet Porosity Value: 1.0%

Rod Diameter: 6.0 mm Formwork Type: Laser-Cut MDF Surface Finish: Polypropylene Sheet Porosity Value: 0.5%

(photos taken by Koey Mo)

C2.2 Prototype b: Fabrication Sequence

1. Formwork assembly 2. Plastic dropsheet and polypropylene is placed onto the formwork 3. Placement of acrylic rods

8. Alternatively, if foam formwork is used, a hot wire cutter is used to cut and remove it

4. Concrete mixing

9. The rods are trimmed with a dremel

5. The mix is cast onto the formwork

10. The voussoirs are polished and washed

6. A plastic membrane is placed on top of the 88

formwork while the concrete sets 7. Formwork removal

(photos taken by Koey Mo)

3.0 mm rods

6.0 mm rods

C2.3 Performance of acrylic rods The prototypes performed satisfactorily in regards to emitting light through the voussoir. As seen in the photos above, either rod diameters had no issue letting light through (the effects above were created by indirect sunlight). As expected, the rods with the larger diameter produces a stronger light effect, hence they are preferrable. As long as shade is present, the rods will produce an evident contrast of light and dark,

C2.4 Formwork Issues The laser cut formwork does not produce accurate angles in order for the contact faces to be fabricated correctly. The notches between the laser-cut pieces do not have a perfect fit, as the voussoir geometries have to account for 3 axes, whereas laser cutting can only process 2 axes. As shown by prototype A, even subtle tolerances cannot be allowed. Additionally, the algorithm used does not produce fully planar contact faces, which further increases the inaccuracy of the formwork geometries.

C2.5 Surface Finish

i - Taping:

ii - Plastic Drop Sheet:

The use of tape produced a smooth finish, but with straight scores between the overlapped tapes. It is also a time-consuming process and is impractical for producing 1:1 voussoirs.

Arbitrary folds are produced on the surface of the prototype. Fragments of plastic are also stuck to the concrete.

iii - Polypropylene Sheet over the drop sheet: Produces a very smooth surface. Drawback is that more material wastage is created.

Different issues arose from each attempt. In the end, we learnt that in order to produce acceptable results, CNC milled foam formwork is the best option for producing accurate geometries, but at the cost of a lot of wasted foam. As for surface finishing, we believe that formwork mould oil would be the best option. It can be purchased in bulk and quickly sprayed onto the foam and MDF base to produce a smooth and even coating and finish without compromising the dimensions of the voussoirs. 91

C3 Final Detail Model

C3.1 Constructability Of Voussoirs From the prototype in PartB, we have made the following improvements: 1 Using glue as a connective agent between each 3D-printed piece, as part of our decision to implement mortar in our shell, instead of dry construction as done in the Armadillo Vault 2 Ensuring that tessellations are regular and consistent, and that edges are smooth, as already mentioned and explained in C1.2. 3 Ensuring that the falsework geometries are identical to the positions of the voussoirs. It was found that the accuracy of the falsework is crucial to making sure that the voussoirs will converge properly from all 3 supports. 94

The main issue that we ran into is that the 3d printed panels must be carefully and precisely placed to ensure every voussoirâ&#x20AC;&#x2122;s contact faces can fully meet each other. In our aim to finish building the prototype within a 5 hour time frame, we ended up with subtle gaps between each voussoir. To our surprise, the final piece could not fit (refer to photo above), resulting in a substantial gap. One possible explanation is that the distance between each gap accumulated and resulted in this problem. Additionally, we realised that small tolerances must be accounted for in the perimeter of each voussoir so that the mortar can be used without disrupting the fit between all voussoirs.

C3.2 Process of construction

C4 Conclusion

At the start of the semester, I learnt that computation can be used to optimise formal and structural qualities of a design, as well as significantly speed up the fabrication and construction process of a project. This project taught me that as simple as that sounds, a huge amount of preparation needs to be undertaken before that can be achieved. I’ve understood that digital optimisation requires a deep understanding of algorithmic thinking paired with established mathematical theories in order to be properly executed. I’ve also learnt about the level of detail that goes into a project that requires extreme precision. Likewise, the use of digital tools to speed up the construction process cannot be achieved without rigorous planning and precise assembly of components. In our case, even the setting up of the falsework needs to be planned out to a considerable degree. In trying to imitate the design process of the Armadillo Vault, I have developed a new-found respect for designers and engineers who are able to organise and manage the construction of complex forms. Throughout the semester, I have experienced the process of solving a unique algorithmic task of creating a shell structure through discretised elements. I have learnt that using grasshopper is a process of identifying and solving issues in a step by step process, and that it is possible to create a unique grasshopper definition if I put enough thought and research into it. I was also involved in a design process whereby we were only able to make certain design decisions after prototyping. Specifically, we were only able to feel confident that the concept of ‘porous’ cibcrete was possible after our prototypes in part B, in which we made major improvements to in part C. Overall it was an engaging experience.