From File to Factory: Advanced Manufacture of Engineered Wood Elements

From file to factory: Advanced manufacture of engineered wood elements

Part 1: Innovative design solutions for multi-storey timber buildings throughout the entire building process Part 2: Application to project Zembla in Kalmar, Sweden

Magnus Larsson Alex Kaiser Ulf Arne Girhammar

From file to factory: Advanced manufacture of engineered wood elements

Part 1: Innovative design solutions for multi-storey timber buildings throughout the entire building process Part 2: Application to project Zembla in Kalmar, Sweden

Magnus Larsson Alex Kaiser Ulf Arne Girhammar

Luleå University of Technology Department of Engineering Sciences and Mathematics Division of Wood Science and Engineering ISSN 1402-1528 ISBN 978-91-7790-870-8 (print) ISBN 978-91-7790-884-5 (pdf)

Luleå 2020 www.ltu.se FROM FILE TO FACTORY: Advanced manufacture of engineered wood elements – Part 1: Innovative design solutions for multi-storey timber buildings throughout the entire building process

Magnus Larsson1, Alex Kaiser2, Ulf Arne Girhammar2,*

1 Former Luleå University of Technology, Sweden 2 Division of Wood Science and Engineering, Luleå University of Technology, 931 87 Skellefteå, Sweden

ABSTRACT: “File-to-factory” processes of computer technologies is a contemporary way to both maximise efficiency throughout the building process, increase a building's performance, and be able to add interesting architectural possibilities throughout the design phase. Viewing the building as a parametric network of connected components that can be individually controlled through unique parameters may no longer be a novel architectural concept, but its application to multi-storey timber buildings is still a territory for which there are no maps. Allowing not only the notion of identicality in mechanically reproduced objects to be left behind, but replacing the idea of the object with that of the objectile, the authors investigate a novel approach that produces a set of building trajectories rather than a set of buildings, yet yields a series of buildable examples of those trajectories. This paper describes and evaluates how this series of stacked multi-storey timber buildings based on three Swedish timber structural systems can be both incorporated within a file-to- factory process, and how this gives rise to a range of new and interesting potentials to create innovative solutions throughout the entire design and manufacturing process.

KEYWORDS: Wood architecture, multi-storey timber buildings, file-to-factory, parametrics, modular systems, objectile, gridshell, living capsules.

1. Introduction

Before Leon Battista Alberti introduced orthographic projections in the 15th century in order to secure identicality in the executions of his designs, architecture was essentially a handmade art. Like signatures written by a human hand, buildings might be similar, but they were never identical. Following Albert, machines were invented that used casts, molds, matrices, and stamps: humanity entered the age of mechanical reproduction. It is only in the past half century that we have begun to move away from this technical logic of industrial modernity's identicality towards a new digital – and therefore inherently variable – design paradigm [1].

Digital manufacturing per definition creates one-off objects. Serial variations tend to come at no additional cost. Furthermore, digital processes tend to merge the two production modes of complex objects such as buildings: the initial phase of the design object as a collection of notational media representations are controlled using the same software that instructs the manufacturing machine to build the final physical object. While the digital design process brings contemporary architecture closer to its primeval mode (of simultaneous conceiving and making), the digitally controlled manufacturing process turns the factory into a computer- aided version of the artisanal workshop.

Digital manufacturing makes it possible for standard building materials and processes to result in non- standard architecture. File-to-factory strategies can further assist this operation. In this paper, we explore how such digital tools can be applied to a series of example buildings based on three Swedish timber structural systems, described in Abstract A [2]. A preliminary version of this paper was earlier presented at a conference [33].

2. File-to-factory and data-to-site feedback loops

In a 2011 essay, Hani Buri and Yves Weinand discuss how different technological ages have influenced the tectonics of timber structures, from the artisanal “wooden age” through to our present “digital age”. Having established that the “ability to control machines with the help of a computer code eliminates the need for

* Corresponding author. E-mail address: [email protected]. Tel.: +46 70-36 268 15. 1 serial production,” the authors continue to explain that the easy machinability of wood “makes it an ideal material for digitally controlled processing portals,” which has led to timber “taking on the status of a high- tech material” [3].

Add to this digitally controlled processing of a high-tech material today’s possibilities for having different systems communicate with each other, and we end up with a highly flexible process where computer-aided manufacturing (CAM) and computer numerically controlled (CNC) technologies are linked to parametric design software and, possibly, even live-fed contextual data from the site in question. This would form a file- to-factory operation that would make it possible to manufacture individualised building components in a highly economical manner. The various parts would not only be adapted to fit perfectly together, forming a network of interlinked relationships, but would also acquire a new, time-based property: as it is analysed and tested before being inserted into the scheme, the component adapts to analytical data; once it has been installed, if fitted with a sensor, it can continuously feed data back into the system, reporting on its on status within the framework of the building. Such a data-to-site feedback loop would not only maximise efficiency throughout the building process, but also increase the building's performance while adding interesting possibilities of influencing the architectural palette during the extended design phase over time. Eventually, architecture could literally be published into this information network.

While this Internet of Things-based vision is beyond the scope of this paper, an exact file-to-factory system is particularly appealing when it comes to engineered timber architecture, as accuracy is of the essence. Designing a building that is to be constructed from elements that will be pre-cut, offsite, to the architect’s specifications means that everything must be finalised at the drawing board. The design must be finished when it leaves the architect’s office. This is essentially a production strategy in mass customisation (based on file-to-factory processes), which should be evident both in the formal expression and in the programmatic functionality of the final building. New manufacturing methods give rise to new structures, new ways of using those structures, new architectures.

3. Post-parametric post sustainability

The growing urbanization of the planet, visible in the fact that by the middle of this century some 70% percent of the population will live in cities [4], situates the urban question as a key issue for the global environment. As architects and engineers, we need to engage with the questions arising from current analyses of a world in which about 3.4 billion people are concentrated on roughly one percent of the earth’s surface, consuming 75 percent of the world’s energy use and producing 80 percent of our total CO2 [5], and predictions that in 2050 the world’s population will increase to 9.3 billion and the urban population will double to 6.8 billion [6]. Our metropolitan areas is where density can allow us to live extraordinarily energy efficient lives; as David Owen observed in an article in The New Yorker, “Eighty-two per cent of Manhattan residents travel to work by public transit, by bicycle, or on foot” [7].

We hesitate to call this a “sustainable” urbanist outlook, as we are rather seeking a post-sustainable condition. Humanity needs to move beyond practices that merely do no more harm, we need to readjust our environmental strategy to focus on continuous improvement rather than mere sustainability, and the city is the obvious place to start, not the least because the metropolis is where change is most easily implemented. To quote Edward Glaeser, urban density “creates a constant flow of new information that comes from observing others’ successes and failures... Cities make it easier to watch and listen and learn. Because the essential characteristic of humanity is our ability to learn from each other, cities make us more human”[8].

In a provocative 2004 essay, David Schaller points out that “a typical coffee business uses 0.2 percent of the coffee bean to produce a cup of coffee. This means 99.8 percent of the coffee bush becomes ‘waste’”. According to Schaller, there is “an abundance to nature that, in our ignorance and even arrogance, we are only beginning to fathom... Our microbiologists, botanists, biologists, mycologists, wood chemists and geneticists are only now scratching the surface of this great diversity and plenty. What we don’t understand, we can’t possibly explain, value, or protect”[9].

The choice of timber for a tall structure of this massive scale is a very modest proposal that could perhaps open up one line of inquiry into this unharvested natural abundance. The earth contains about one trillion 2 tonnes of wood, which grows at a rate of 10 billion tonnes per year [10].0 As an abundant, carbon-neutral or even carbon-negative renewable resource, timber is the only readily available building material that stores carbon dioxide, minimises or eliminates its carbon footprint, and hence is truly post sustainable.

Urbanising literally means “burying,” but we are not interested in burying the agricultural or suburban landscape. Rather, we want to celebrate the ground datum as a counterpoint to the necessary further densification of our urban nodes. By having the structure undulate across the topography, touching the ground in as few places as possible, we can potentially achieve a dichotomy between landscape and urbanism allowing the project to reverse today’s migration patterns, bringing the city to the people living in less densified areas. It redefines the notion of sprawl, turning it into a progressive tactics for linking the city infrastructure to the rural outskirts of our urban conglomerations, extending the metropolitan condition.

The tall, sprawling, habitable timber network presented here is post sustainable in three major ways: through its reinterpretation of the urban condition and introduction of a new typology that can promote new ways of living, through its materiality as explained above, and through the systemic approach at its heart, which employs file-to-factory processes to not only minimise waste but lower the degree of processing while creating a structure that is easily manufactured, assembled, and maintained.

We also view it as being post parametric. Here a very brief commentary is given. In 1967, Marshall McLuhan claimed that transformative new technologies eventually turn superseded technologies into “counter-environments” [11]. The counter-environment of the Romantic landscape, for instance, is the railroad and factory of the industrial age. Counter-environments change the nature of perception, and by extension the opportunities for intervention.

Parametric techniques in architecture – geometric models whose geometry is a function of a finite set of parameters – have prevailed since at least the Bauhaus, or Gaudí, or the Baroque, or the Gothic, depending on how we choose to frame the concept [12]. While still toted as the next big thing in architecture, parametric design as a conceptual framework (there is no design without parameters) should by now have been brought into a counter-environment-like relief ready to be re-assessed and built upon by new theorists. What we mean by calling this building post parametric is that it seeks to harness something completely different from the BIM models being celebrated by the corporate machine – an open source system that acquires, processes, and integrates data into a cloud environment that allows the building to “learn” from its context and inform the system that generates its next section about this knowledge in order to optimise its own performance, a signal network that could perhaps be likened to how the human peripheral nervous system connects the central nerve system to our limbs and organs.

4. Scale, structure, precedents

The building presented here is massive. It’s scale goes beyond that of the building or even the urban block, towards the city itself. It is a megastructure, an enormous, self-supporting artificial construct. It is a plug-in grid-shell, a huge canopy weather-sealed by living units, an oversized tribute to that great traditional British form, the Pavilion in the Park.

The hybrid structure is a combination of three Swedish timber building systems: a CLT/glulam lattice from Martinson’s, regular along the x and y axes but locally irregular along the z axis, undulates across the landscape, supported at points by large-scale L-beams from the Moelven Wood 8 system, which also double up as circulation and service spaces. Within this timber lattice – a wooden grid-shell somewhat reminiscent of a scaled-up version of Frei Otto’s 1975 Multihalle Mannheim structure, Buro Happold’s 2006 Savill Building, or maybe Barkow Leibinger’s Company restaurant with auditorium in Ditzingen [13] – prefabricated, pod-like living units (capsules) manufactured using the Byggma Masonite Flexible Building System are inserted, effectively hung from the gridded framework, thus challenging the notion of compressive or subtractive stacking. See Figs. 1 – 3.

Fig. 1. The structural system: The black lattice is from Martinsons, the grey L-beams from Moelven, and the white living units from Byggma.

Fig. 2. Perspective of the scheme as it undulates across the landscape and creates its own topography high above the ground. Units are hung from the gridded framework, challenging the notion of compressive or subtractive stacking.

(a) (b)

(c)

Fig. 3. Some details of the building area: (a) the hanging living units above a landscape; (b) the hanging living units above or near a water area; and (c) the hanging living units behind a main beam of the grid.

It is impossible not to mention Jurgen Mayer H’s giant latticed timber canopy, a part of their redevelopment of the Plaza de la Encarnacíon in Seville, Spain. This scheme, finalised and opened to the public in April 2011, includes an archaeological museum, a farmers market, an elevated plaza, an aerial walkway, as well as bars and restaurants, all contained beneath and within the parasol structure.

Why is it so big? Mainly because it can be. Myron Goldsmith writes about the ultimate size for structures and the principles dealing with the effects of magnitude, going back to the teachings of Galileo and Sir D’Arcy Wentworth Thompson, concluding not only that every structure has a maximum and a minimum size, but also that size and scale “have important implications environmentally and functionally. Engineering for efficiency is not the last and only determinant; it is possible to make a choice from several efficient schemes because of architectural, aesthetic, and environmental reasons. The human needs must give the directions” [14].

There are three other main reasons for the vast scale of this project. The first is that we are interested in investigating this new typology of upside-down stacking at the largest end of the spectrum, where the beams making up the lattice are large enough to hold circulation paths and other programmatic features, and principles of mass manufacturing and prefabrication can be challenged to exhaustion (for instance with entire living pods being manufactured under factory conditions). The second is a challenge to the prevalent romantic view that environmental or even social concerns are somehow connected to scenic pleasures and aesthetic appreciations of the picturesque: “nature” is not passive but has always been an active agent in the co-production of our civilization while co-developing with it [15]. By creating a building large enough to

5 hold nature – in the form of tree/forest plantations – within itself, we comment on this misapprehension. The third is an extension of the renewable material’s properties: a building made from wood is a carbon dioxide store, and building with timber (for as many inhabitants as possible) can be viewed as a form of active climate protection.

An increase in size is not necessarily accompanied by a decrease in efficiency. As long as we don’t exceed the strength of the material, a larger structure will resist for instance wind forces better than a smaller one. Ecologically, large-scale buildings and structures can be very destructive or, when carefully controlled, lead to great benefits. Done right, they can enhance the environment and protect human and planetary health. At the scale of the city, this building embodies the ideal of the Japanese Metabolists – never a group to hold back in terms of scale: a technological fervour bringing about future cities made from large-scale, flexible, and expandable structures that evoked the processes of organic growth [16]. That basic unit of Metabolism, iterated to perfection by Kisho Kurokawa, the prefabricated capsule, is important also to this scheme. Kurokawa’s 1960 Neo-Tokyo Plan and grid system on stilts, Agricultural City, as well as his capsule-within- space frame 1969 Odakyu Drive-in Restaurant, and of course his 1972 Nagakin Capsule Tower, are all somehow related to the present project, as is other Metabolist proposals such as Arata Isozaki’s 1960 Clusters in the Air and perhaps the 1961 elevated Disaster Prevention City by Kiyonori Kikutake [17].

5. Some assembly required: Prefabrication

Prefabrication is often referred to as “architecture’s oldest new idea” [18] – and for good reason. Not only has it been around for thousands of years, it has also been touted as the next big thing in architecture for about as long. When the newly-weds played by Buster Keaton and Sybil Seely have their prefab timber house delivered in the 1920 silent short film One Week [19, they are already at the closing end of the first chapter in the history of prefabrication, a narrative that might have started with the giant prefabricated structures erected in ancient Sri Lanka under Sinhalese kings two millennia ago, and continued with a wide range of architectural projects including the wooden panelised buildings the British used to house their fishing fleet in the 17th century; the Crystal Palace in 1851; the kit house of numbered, pre-cut pieces sold by Aladdin Readi-Cut Houses from the early 20th century; the wildly popular Houses by Mail program established by Sears Roebuck & Co in 1908; Swiss architect Le Corbusier’s structural frame Maison Dom- ino in 1914, and the same architect’s short treatise Mass Production Houses, the penultimate chapter from his famous book Vers une architecture, which in 1919 introduced the idea of the house as “a machine for living in” [20].

Prefabrication fascinated the architects at the Bauhaus school in Germany, and a year after the Keaton comedy was premiered, prefabrication entered a second chapter with the Baukasten (building blocks) developed between 1922 and 1923 by Bauhaus architects Walter Gropius and Adolf Meyer. These were standardised, industrially produced building elements that could function as a variable kit of parts, interlocking to form a near-infinite array of configurations. The architects would guide the client through this ”oversized set of toy building blocks,” employing a scale model to illustrate possible configurations of the system, assembling different machines for living according to the inhabitants’ needs [21, 22].

Timber is a fitting material for prefabrication. The first prefabricated construction system was the wood- based balloon frame method developed in Chicago by builder Augustine Taylor around 1833, and soon after the timber units making up the Manning Portable Colonial Cottage for Emigrants started shipping from England to Australia. Other interesting timber prefabs include Juhani Pallasmaa’s (with Kristian Gullichsen) 1969 model industrial summer house Moduli 225, the Burst 008 beach house by Jeremy Edmiston and Douglas Gauthier, Oskar Leo Kauffman and Albert Rüf’s 2008 System 3 unit [23], the Breckenridge Perfect Cottage mobile home by Christopher C Deam [24], and MH Cooperative’s tiny Summer Container [25].

Using prefabricated, mass customised plug-in capsules represents a more effective use of resources. It reduces construction times and minimises waste, further reducing the ecological footprint of the plug-in timber grid-shell.

6. Designing the system that designs the building

Just as the history of prefabrication traces the history of modernism in architecture, the history of digital iteration and the ability to respond to individual client needs through the linking of fabrication with computerised design is defining part of the current dialogue.

Digital modes of production open up possibilities for designing with a much closer attention to innovative details, as we now know that (almost) whatever we create on our computer screens can be fabricated digitally at an affordable price. This means, for instance, that we can use a digital sculpting tool such as Z- Brush to modify the surface texture of a wood panel, arrange that same panel in three dimensions via the Panelling Tools plug-in for Rhino and Grasshopper, and then test the properties of the entire arrangement using simulations in climate analysis packages such as EcoTect. Such design strategies, at the very intersection of architecture and engineering, gives rise to entirely new solutions within areas such as acoustics, ventilation, lighting, thermal comfort, and so on. The file-to-factory process also adds another layer of flexibility in that any grid element, structural support, or living capsule can (as long as this doesn’t compromise the structure) be added or subtracted at any time.

We view these buildings as objectiles rather than objects. The objectile is an idea borrowed from the mathematically interested French philosopher Gilles Deleuze and his equally maths-inspired compatriot designer Bernard Cache: not an object but “an algorithm – a parametric function which may determine an infinite variety of objects, all different (one for each set of parameters) yet all similar (as the underlying function is the same for all)” [26]. The objectile is “to an object what a mathematical function (a script or notation) is to a family of curves... The theory of the objectile also implies that the object itself (or the “specific” object) should fall outside the scope of design... since both the object and the event are seen as essentially variable entities” [27].

In other words, we're not so much designing a building as a set of building trajectories, formations that change and evolve over time throughout the design process, as the structure’s contextual circumstances change and its underlying logic is explored further. The designer goes from being the tool user to become the new tool maker (software engineer). He or she edits this trajectory to find the states of the objectile that are most pertinent to the situation at hand. In an almost cinematic procedure, architecture becomes a matter of cutting through the objectiles at the right point, editing and ordering different outcomes; sculpting in time.

That sculpting begins with a topographic analysis of the site itself. The act of measuring its geography turns the territorial continuum of the site into an architectural element or system [28]. This system is then carefully indexed and turned into a topographical network representation of the ground datum, which is raised above ground in a reversal of the typically predatory consumption of land by many urbanisation processes. Shielding the ground below from the wind while offering shadow and even irrigation and/or rainwater distribution possibilities, this matrix canopy initiates a symbiotic relationship with the terrain below.

Additions to this flexible grid call for further analyses. The system becomes a continuously moving factory, trawling the suburban and rural landscape to measure and survey it in preparation for the next stretch of the scheme. The diagram of the site topography that is the grid-shell next becomes the basis for the computation of a set of operational rules, yielding the living capsules through mass customisation scripts, living units that are then “stacked” as they get hung within the structural matrix. The relationship between the local conditions of the grid and the various instantiations of living units is analogous to the way a single genotype might produce a differentiated population of phenotypes in response to diverse environmental conditions.

Despite its scale, the scheme is not as dense as a city; instead of density, we get intensity: the idea of individual buildings holding collective housing gives way for a collective building holding individual housing. The lattice frame itself becomes programmable, holding aerial walkways, terraces, transportation routes. Where a beam changes direction within the lattice, new opportunities for spatial diversity is inserted. While the basic form of the grid-shell is based on the site topography, we now add additional design parameters. Any material construct can be considered as resulting from a system of internal and external pressures and constraints, its physical form being determined by these pressures. Depending on the circumstances, we can decide to exert climate-related forces, apply socioeconomic pressures, or deploy formal variations and deformations at strategic points.

The resulting combinations of lattice-supports-capsules iterate over time as the system keeps updating, creating one objectile after another. Only once the building components have to be manufactured do we freeze the process and collate the data. Postponing the production until the very last minute guarantees that as much information as possible goes into the final, manufactured element and volume. Over time, this material system builds up a complex reciprocity between its materiality, site conditions, form, structure, and space, the related processes of mass customisation and prefabrication, as well as the resulting performative qualities of the structure itself.

7. The File-to-factory process

The present scheme does not sit easily within a common typology. It is very likely that no structure of its kind has ever been built. Non-standard architectures call for non-standard ideas about how to use strategies such as mass customisation and prefabrication in the manufacturing process, though, crucially, it does not necessarily call for non-standard building materials or building processes. While its expression, program, manufacturing process, and design approach are all atypical, it is still a building that can be made by everyday builders from perfectly normal engineered wood.

Recent technological advances enable the materialisation of architectural forms straight from a digital file. As the necessary equipment, machinery, infrastructure, and tools are becoming available to a larger part of the building industry, the manufacturing and fabrication of mass-customised elements according to specific instructions derived from modelling software is becoming increasingly popular. Data-driven fabrication is perhaps particularly appealing when it comes to architecture made from engineered timber, as accuracy is of the essence. Designing a building constructed from elements that are precut, offsite, to the architect’s specifications means everything must be finalised at the drawing board. New manufacturing methods give rise to new buildings, new ways of using the buildings, new architectures.

The plug-in grid-shell structure has been designed to contain a minimal amount of timber elements: beams make up the lattice, cross-laminated sheets add structural support, surfaces (boards) come together to form the living capsules. Nearly all of these components, however, differ from each other, as they are all interlinked through a system that constantly updates our 3d model – a perfect representation of the building at any one moment in time – with new data. Since the building blocks are defined parametrically, they are able to be reprogrammed into essentially carrying out each others’ functions. The machines in the factory don’t know, and don’t care, whether the boards they are instructed to manufacture is to fill the function of a wall or a floor. As Kas Oosterhuis describes it, “Architecturally, convergence sees the beauty in the purest solution, the new modern: one building, one detail” [29].

While our system doesn’t quite go so far as to define a single, parametrically controlled detail, it does take the data from the system and collates it into instructions for the factory, which in turn manufactures the parts in accordance with a predefined time schedule. This makes for an extraordinarily agile building process, where parts can be immediately printed if needed, and new parts pushed to a new place within the work schedule if for some reason the construction program changes (Fig. 3).

Fig. 3. The Grasshopper definition makes for an extraordinarily agile building process. 8

It also completely does away with the need for conventional, two-dimensional drawings. As the design that goes into the centralised three-dimensional project model is converted into instructions that are sent straight to the factory, nothing gets lost in translation. An annotation system makes assembly a matter of simply lining up one marked-up panel against the next, and if a builder needs to double check its placement, he or she can always bring up the latest version of the 3D model on a computer or tablet. The file-to-factory process makes Alberti’s orthographic projections and ideas of identicality redundant: plans and sections become useless descriptions. This enhances efficiency and speeds up the building process. As Mark Burry points out, significant economic benefits can also be derived from “automating routines and coupling them with emerging digital fabrication technologies, as time is saved at the front-end and new file-to-factory protocols can be taken advantage of” [30].

8. Architectural analysis

Living “off the grid” is a trendy way of referring to a self-sufficient lifestyle that doesn’t rely on public utilities (such as the main electricity transmission grid). The building presented here promotes the perhaps less trendy alternative of a communal lifestyle within the grid.

Over and above the obvious environmental credentials – a carbon dioxide store that uses the relatively low density and very high degree of stability (greater, in relation to its mass, than that of steel) of wood to soar above the ground – the plug-in grid-shell is a programmatically interesting alternative to rural or suburban lifestyles, which, as we have seen, are rarely as energy efficient as their urban counterparts. The systemic, adaptive variation and continuous differentiation arising from the dynamic design system, which anchors the project to the site as it continues to shoot through the landscape (in a way perhaps reminiscent of Superstudio’s 1969 The Continuous Monument scheme [31]) offers an interesting contrast between input data and output result, the model/building responding to external pressures according to its own predefined logic.

We have called the capsules living units, but they may also hold other programs: public squares, orchards, swimming pools, shops. In the shade of the structure, we plant seedlings that grow over time into a stretch of forest. Trees are cut down to create this habitable canopy for trees to grow under.

The building also creates its own artificial landscape (Fig. 4), a play between structure and spatial unit that becomes as varied (or, potentially, boring) as the information fed to the system. Depending on the relative density of capsules, in some places, the spatial unit will take formal and programmatic priority over the timber lattice, while in others, the matrix will come to the foreground. But this isn’t the only way in which the system accommodates its local circumstances: it can also adapt to completely different contexts – urban, suburban, rural – and could just as well hug the skyscrapers of New York as climb across the Siberian tundra.

Fig. 4. The building creates its own artificial landscape.

It is an example of how file-to-factory processes can be used to drive the production of a massive structure, but also showcases the possibilities of hybridising different timber building systems. The three Swedish systems we are working with complement each other, supporting an architectural vision that they were clearly never meant to provide for.

9. Conclusions

File-to-factory manufacturing processes can support and give rise to innovative designs that cater for specific situations and contexts. While wood is already regarded as an excellent material for digital manufacturing, few schemes seem to utilise this fact as a structural way forward, at different scales and in order to create a constantly varying and incredibly flexible building. The timber grid-shell presented here is an attempt to fill this gap.

It is also, of course, a provocation. However it is important to remember, in the face of what might at first view come across as a highly radical proposal, that there is nothing to suggest the building presented here cannot be built. All of the technologies we have described already exist, as do the manufacturing processes, the structural possibilities, and the assembly strategies. It is not even that hard to imagine how the financing might work, perhaps with a series of building groups being organised as new stretches of the scheme are created, cutting out the developer middlemen [32].

So what are the theoretical and current practical limits on this form of construction? How high could the lattice rise above ground? How many floors could we add inside the capsules? How would the services work, the circulation paths, the irrigation systems? Would inhabitants be able to customise their own living units? What external pressures should the system respond to? Where is further research needed?

The only way forward is to corroborate those questions and the others outlined or implied in this paper with projects, prototypes, and eventually actual buildings. 10

Acknowledgements

The authors would like to express their sincere appreciation for the financial support from the Regional Council of Västerbotten, the County Administrative Board in Norrbotten, and the European Union: European Regional Development Fund – Regional Structural Fund and Interregional Programmes.

Appendix A. Three Swedish timber structural building systems

A.1 Companies and systems

The study is founded on cross-laminated, panel-and-stud, and post-and-beam timber construction systems from three Swedish companies. The Martinsons Group presents itself as “Sweden's largest producer of glulam, and ... the Nordic leader in wooden bridges and building systems using solid wooden frames,” Moelven claims to be “ the leading producer of glulam in Norway and Sweden,” while Byggma ASA states it is “a leading distributor of building components to the Nordic countries”. Masonite Beams AB, within the Byggma Group, produces wood-based I-beam systems and provides technical solutions to the building industry.

A.2 Martinsons: CLT building system

Martinsons's building system includes a comprehensive range of prefabricated building components that are divided into two mutually supportive tiers. The first of these features glulam frames made from finger- jointed boards that are glued together to form long structural members, and which are used for the post-and- beam construction of large open spaces. The second tier features pre-fabricated solid or cross-laminated timber (CLT) components that go together into multi-storey blocks of flats, and multi-layered wooden boards forming elements that can be prepared with electrical/ water pipe fittings and sound proofing (built-in sound insulators provide sufficient acoustic levels internally, while the finished elements satisfy sound transmission class B). This study focuses on Martinsons's building system with CLT panels, with which the company has completed buildings up to eight storeys to date [34].

A.3 Moelven: Timber 8 modular system

Moelven supplies both standardised solutions and constructions tailored to specific requirements. Their flexible system solutions are roughly divided into three tiers: laminated load-bearing timber constructions, interior systems, and different building modules. The latter are used for both temporary and permanent buildings, and are produced under ideal conditions indoors, reducing the workforce on the building site. Moelven are also able to fit their modules with electrical installations. Their interior systems are tailor-made and delivered ready to assemble. Moelven's Trä8 Modular System is a post-and-beam system with specially manufactured stabilising elements: box-type components made of glulam core members and laminated veneer lumber (LVL) sheathing. The stabilising elements act as a cantilever anchored to the foundation up to a height of four storeys [35].

A.4 Byggma: Masonite Flexible Building system (MFB)

The Masonite Flexible Building (MFB) system is based on prefabricated units, and meets prevailing requirements regarding fire safety, moisture conditions, strength, stabilisation, thermal comfort, and acoustic insulation. The MFB system consists of prefabricated wall, floor and roof elements that come flat packed and are assembled on site. Lightweight timber I-beams are integrated with a composite laminated panel (plyboard) to form a rigid frame for wall and floor elements. Intended at present for buildings up to eight storeys and floor spans up to eight meters, the elements meet fire requirements of REI 60 and noise requirement class A. It is believed that the plyboard wall panels combined with I-studs and the suspended floor elements make the MFB system adaptable for up to 20-storey buildings [36].

References

[1] For a good introduction to Alberti and the historical development from mechanical to digital design, see Mario Carpo, The Alphabet and the Algorithm, MIT Press, Writing Architecture series, 2011.

[2] Magnus Larsson, Alex Kaiser, Ulf Arne Girhammar. Multi-storey modular manoeuvres – Innovative architectural stacking methodology based on three Swedish timber building systems. World Conference of Timber Engineering, Auckland, New Zealand, 15-19 July, 2012.

[3] Hani Buri and Yves Weinand. The Tectonics of Timber Architecture in the Digital Age, in Hermann Kaufmann and Winfried Nerdinger, Building with Timber – Paths into the Future, Pretzel, Munich, 2011, pp. 56-63.

[4] The United Nations, World Urbanization Prospects: The 2007 Revision (United Nations, 2008). Available online: http://www.un.org/esa/population/publications/wup2007/2007WUP_ExecSum_web.pdf.

[5] Siemens AG (Hrsg.): München – Wege in eine CO2-freie Zukunft, Siemens AG, 2009. Available online: http://www.wupperinst.org/uploads/tx_wiprojekt/CO2-freies-Muenchen.pdf.

[6] UN Population Division, World Population to reach 10 billion by 2100 if Fertility in all Countries Converges to Replacement Level, Population Division, UN Department of Economic and Social Affairs, 2011. Available online: http://esa.un.org/unpd/wpp/Other-Information/Press_Release_WPP2010.pdf.

[7] David Owen, Green Manhattan: Everywhere Should be More like New York, The New Yorker, October 18, 2004, p. 111.

[8] Edward Glaeser, Triumph of the City: How Our Greatest Invention Makes Us Richer, Smarter, Greener, Healthier, and Happier, Macmillan, 2011, p. 247.

[9] David Schaller, Beyond Sustainability: From Scarcity to Abundance, BioInspire 13, 2004. Available online: http://bioinspired.sinet.ca/content/february-2004-beyond-sustainability-scarcity-abundance.

[10] Horst H. Nimz, Uwe Schmitt, Eckart Schwab, Otto Wittmann, Franz Wolf, Wood in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, 2005.

[11] Marshall McLuhan, The Invisible Environment: The Future of an Erosion, Perspecta, 1967.

[12] Daniel Davis, Patrick Schumacher – Parametricism, blog post, 2010. Available online: http://www.nzarchitecture.com/blog/2010/09/25/patrik-schumacher-parametricism/.

[13] All of which are presented in Hermann Kaufmann and Winfried Nerdinger, Building with Timber – Paths into the Future, Pretzel, Munich, 2011.

[14] Myron Goldsmith, The Effects of Scale in Werner Blaser (ed.) Myron Goldsmith –Buildings and Concepts, Rizzoli, 1987, pp.8-23.

[15] Cary Siress, Sustaining what? The Discourse of Sustainability in Need of Re-invention in Ilka & Andreas Ruby, Re-inventing Construction, Ruby Press, 2010, p. 436.

[16] Zhongjie Lin, Kenzo Tange and the Metabolist movement: urban utopias of modern Japan, Routledge, 2010.

[17] For an unparalleled excursion into the world of the Metabolists, see Rem Koolhaas and Hans Ulrich Obrist, Project Japan – Metabolism Talks, Taschen, 2011. 12

[18] Kimberley Stevens, Can Prefab Deliver?, in The Architect’s Newspaper, 16 July 2008. Available online at http://archpaper.com/news/articles.asp?id=1877.

[19] One Week, directed by Buster Keaton and Edward F. Cline, Metro Pictures, 1920, available online at http://video.google.co.uk/videoplay?docid=3147358394537366471.

[20] Le Corbusier, Toward an Architecture, Frances Lincoln, 2007.

[21] Gilbert Herbert, The Dream of the Factory-made House: Walter Gropius and Konrad Wachsmann, MIT Press, 1984.

[22] Barry Bergdoll and Peter Christensen, Home Delivery: Fabricating the Modern Dwelling Birkhäuser, 2008. An excellent website accompanies this book and the exhibition (Home Delivery) it supported: http://www.momahomedelivery.org/.

[23] Ibid. All shown at the Home Delivery exhibition and its accompanying website.

[24] Ruth Slavid, Micro – Very Small Buildings, Laurence King, 2009, pp 114-115.

[25] Ibid., pp 146-147.

[26] Mario Carpo, ibid., p. 40.

[27] Ibid. pp. 47-48.

[28] Vicente Guallart, GeoLogics, Actar, 2008, p. 11.

[29] Kas Oosterhuis, Cockpit Building in an AcousticBarrier, 2004. Available online: http://www.oosterhuis.nl/quickstart/fileadmin/Projects/142%20Cockpit/02_Papers/040831-Hessing- Cockpit_paper.pdf.

[30] Mark Burry, Scripting Cultures: Architectural Design and Programming, Architectural Design Primer, John Wiley & Sons, 2011.

[31] Peter Lang and William Menking, Superstudio: Life without Objects, Skira, 2003.

[32] Christian Roth & Sascha Zander, Architecture Without Developers in Ilka & Andreas Ruby, ibid., pp. 419-432.

[33] Magnus Larsson, Alex Kaiser, Ulf Arne Girhammar, From File to Factory: Advanced manufacture of engineered wood elements – Innovative design solutions for multi-storey timber buildings throughout the entire building process, World Conference of Timber Engineering, Auckland, New Zealand, 15-19 July, 2012.

[34] Cf. http://www.martinsons.se/home.

[35] Cf. http://www.moelven.com/Products-and-services- COM/Glulam.

[36] Cf. http://www.byggmagroup.se/dt_article.aspx?m=2574 (in Swedish).

FROM FILE TO FACTORY: Advanced manufacture of engineered wood elements – Part 2: Application to project Zembla in Kalmar, Sweden

Alex Kaiser1, Magnus Larsson2, Ulf Arne Girhammar1,*

1 Division of Wood Science and Engineering, Luleå University of Technology, 931 87 Skellefteå, Sweden 2 Former Luleå University of Technology, Sweden * Corresponding author. E-mail address: [email protected]. Tel.: +46 70-36 268 15.

Abstract: A “file-to-factory” process of computer technology is applied to a real project called Zembla in the town of Kalmar, Sweden. The ground datum is used as a counterpoint to the necessary further densification of our urban nodes. It redefines the notion of sprawl, turning it into a progressive tactics for linking the city fabric to rural areas. It is a post-sustainable file-to-factory-produced timber ground-scraper that redefines the urban-rural edge of Kalmar; soaring high above ground and water, suggesting a new way of life through a new way of making city-sized buildings for the future. A plug- in grid-shell structure is designed to contain a minimal amount of timber elements, beams make up the lattice, cross-laminated panels add structural support, surfaces (boards) come together to form the living capsules. Having the structure undulate across the topography and touching the ground in as few places as possible uses the dichotomy between landscape and urbanism to allow the project to reverse today’s migration patterns, bringing the city to the people living in less densified areas. The living units are placed in into the grid. Each unit is unique and is customised to its weather and topological conditions within the grid. Some comments on grid development and slotting is also given as part of the file-to-factory process.

KEYWORDS: Wood architecture, multi-storey timber buildings, file-to-factory, parametrics, modular systems, grid-shell, living capsules, grid development, slotting.

1. Introduction

The idea is to investigate how contemporary file-to-factory process can be used to drive new manufacturing technologies such as CNC milling of wood. The end goal – the ambitious one – is to build a tool that allows us to input a series of values for different parameters such as building system, site topography, chosen typology, etc. as well as “hard” and “soft” data: climate information and internal features such as circulation, for instance. This data is then to be used as raw material for the tool, which spits out a finished building, ready to be cut by a CNC machine, at the other end of the process. The digital tool will be built in Rhinoceros using the Grasshopper plugin, an interface that allows for visual scripting of 3D geometry.

The architectural idea behind the building is that of the super grid, a take on radically avant-garde Italian architecture collective Superstudio’s famous scheme, The Continuous Monument. Another precedent is the megastructures of the Japanese Metabolist movement. We envisage a project that begins with the grid as an organisational vehicle, which meets existing timber construction systems to produce a grid-shell structure, which in turn holds a series of parametrically controlled living units.

Since they were pioneered in 1896 by Russian engineer Vladimir Shukhov in constructions of exhibition pavilions of the All-Russia industrial and art exhibition 1896 in Nizhny Novgorod, gridshells have of course been used in many architectural schemes, including Frei Otto’s Mannheim Multihalle, Edward Cullinan’s Weald and Downland Open Air Museum in Sussex, and Shigeru Ban’s collaboration with Frei Otto for the Japan Pavilion at the Expo 2000 – a unique grid-shell design made from circular paper tubes.

As far as we know, however, grid-shell structures have never before been used as a supporting megastructure inside of which living units are “hung”, see an illustration in Fig. 1. One of the main 1 reasons for creating a timber structure at this huge size is environmental: it will be argued that using timber to construct oversized carbon dioxide storage structures is a highly sustainable, even a post- sustainable, action. Part of the argument is also about countering the devastating effects of the post- war phenomenon of sprawl, predominantly in the US.

The topic of mass customisation will be key to our investigation. In the succinct wording of Economist magazine, mass customisation is “a production process that combines elements of mass production with those of bespoke tailoring. Products are adapted to meet a customer’s individual needs, so no two items are the same”. In the world of architecture, we might take this even one step further: each element of our structure can be individually tailored to perfectly meet the demands of our design, yet manufactured as quickly as if the same element was being mass produced, under factory conditions, through the use of digital methods.

Fig. 1. Perspective of the scheme as it undulates across the landscape and creates its own topography high above the ground. Units are hung from the gridded framework, challenging the notion of compressive or subtractive stacking.

This Part 2 is a companion paper to the paper “From file-to-factory”, Part 1 [1], and focuses on the application of the principles discussed in Part 1 together with some supplementary issues.

2. Background

2.1 Grid development

Timber space grid structures are rare in comparison with their steel or aluminium counterparts. However, in Japan, there is a tradition of building large-scale structures, such as temples, castles and pagodas [2].

The grid development is the basic start. Emblematic of modernity, the grid is the underlying form of everything from skyscrapers and office cubicles to paintings by Mondrian and a piece of computer code. And yet, as Hannah Higgins [3], the grid has a history that long predates modernity; it is the most prominent visual structure in Western culture. Higgins examines the history of ten grids that changed the world: the brick, the tablet, the gridiron city plan, the map, musical notation, the ledger,

2 the screen, moveable type, the manufactured box, and the net. Charting the evolution of each grid, from the Paleolithic brick of ancient Mesopotamia through the virtual connections of the Internet, Higgins demonstrates that once a grid is invented, it may bend, crumble, or shatter, but its organizing principle never disappears. The appearance of each grid was a watershed event. Brick, tablet, and city gridiron made possible sturdy housing, the standardization of language, and urban development.

Céline Paoli’s thesis “Past and Future of Grid-shell Structures” [4] is the bible for this part: “Because of their original organic shape and the column free space that they provide, the design of grid shell structures challenges architects and structural engineers in more than one way. Very few grid shell building exist around the world. This scarcity may be explained by the level of innovation required in such fields as design technique; construction scheme, use of material ... The construction of a timber grid shell starts from a flat, two dimensional wooden net, the three dimensional shell type structure is then achieved by pushing on the edges of this mat and gradually releasing the internal stresses at the joints to enable the shape to live and the structure to take its most adequate form. … by studying the way they work and behave, as well as the process that lead to the choice of such a structure, we’ll understand how grid shell were born in the mind of architects and structural engineers.”

M. H. Toussaint [5] points out: “The formation process of a grid-shell results in bending and torsion stresses in the members. After relaxation of the timber, a residual stress level remains in the structure. This stress has to be accounted for in structural analysis. The stress levels can be derived from the curve angles in the structure. These angles are part of the output of the grid-shell design tool and can therefore easily be utilised.”

Grid plan is a type of city plan according to Wikipedia [6]: “The grid plan, grid street plan or gridiron plan is a type of city plan in which streets run at right angles to each other, forming a grid. In the context of the culture of Ancient Rome, the grid plan method of land measurement was called Centuriation.”

From the architectural point of view it can be mentioned that the architectural grid, as an instrument of design, is omnipresent in the work of architects whatever the times or the societies we may take into consideration [7]. The structural grid creates valid spaces and voids, thus allowing for the user to walk above, within, or below the house. The void modules of the structural grid allow for the lush environment to continue within the areas of the residence as trees grow within the null space [8].

Concerning recursion as part of the grid development, Wikipedia [9] states: “Recursion is the process a procedure goes through when one of the steps of the procedure involves invoking the procedure itself. A procedure that goes through recursion is said to be ‘recursive’. To understand recursion, one must recognize the distinction between a procedure and the running of a procedure. A procedure is a set of steps that are to be taken based on a set of rules. The running of a procedure involves actually following the rules and performing the steps. An analogy: a procedure is like a written recipe; running a procedure is like actually preparing the meal.”

When it comes to sprawl, Joshua Arbury [10] traces many aspects of both sprawl and the compact city typology: “Although most future urban population growth will come in developing world cities ... per- capita resource consumption rates of these cities pale into insignificance compared with developed world cities, particularly low-density ‘sprawled’ cities in North America, parts of Europe, and Australasia. It is for this reason that focusing on improving the sustainability of developed world cities is so critical, as there is much to gain and more resources available than in developing world cities to help achieve more sustainable urban futures. Of particular concern in these ‘sprawled’ cities is both the loss of surrounding natural land, as urban development spreads rapidly into previously productive or environmentally significant land, as well as increasing concerns about the environmental effects of automobile emissions, particularly in relation to climate change.”

A completed development of the grid using a digital tool is illustrated in Fig. 2a and a physical model of it made in parts using a CNC machine in Fig. 2b. Fig 2a is the grid definition for the physical

3 model. A script was made that automated the production of the connections between struts, based on the capabilities of our 3D printer. So each piece took into consideration tolerances needed to be functionally put together. It was looking at base methodologies we would need to consider when scaling this methodology up. Fig 2(b) is a visual representation of the grid structure. The nodal points of the grid are those that touch the ground.

(a) (b) Fig. 2. Illustration of (a) a completed definition of the grid using the digital tool and (b) its physical model made in parts using a CNC machine.

2.2 File-to-factory process

The file-to-factory process and contemporary digital manufacturing technique are described in the companion paper [1]. Here some additional background and comments are given.

The contemporary blur between the areas of digital design and fabrication, in which the design process merges into fabrication as data is directly transferred from a 3D modelling application to a CNC (Computer Numerically Controlled) machine, is the basis of this entire project. File-to-factory methodologies seem to be a rather new phenomenon, largely unique to the fields of architecture and (industrial) design. They can be utilised at many different stages of the design process: as a vehicle for form-finding exercises in which digital 3D models and physical models complement each other, as concurrently running (structural/volumetric/programmatic/aesthetic/performative) simulations, as reverse engineering processes based on physical models getting translated into digital representations, as real-time behaviour buildings that can be programmed to react and respond to their environments, and through file-to-factory strategies where the design process is seamlessly merged with the manufacture of the designed object(s) through digital fabrication. This refers to the use of programmable CNC machines and fabrication through subtractive and additive techniques, allowing for the production of small-scale models as well as full-scale building components straight from digital 3D models [11].

The fabrication process can be manipulated through formal acts such as slicing, folding, tiling, carving, and slotting. Each of these digital fabrication methods draws its roots from traditional practices of building and making, and utilizes computer technology as a tool with tremendous possibilities in those processes. Slicing, for instance, would be cutting through the digital model to create a 2D view that can be processed by the computer-driven milling machine. Folding is based on the techniques of origami, beginning with a flat surface and creasing the plane at different angles and directions to create a much stronger three-dimensional object out of a material that had a much smaller rigidity as a single plane. Tiling uses multiples of the same or similar objects to create a multiplying effect. Carving is the same as traditional sculpting but with digital tools, cutting away from materials to create nearly anything imaginable. Slotting, finally, is what we are primarily interested in here: creating jointed objects that slide into and out of each other.

As Larsen and Schindler [12] point out concerning digital CNC manufacturing of wood, the potential to design “whatever non-regular shape imaginable with the aid of modern CAD systems has

4 successfully entered the realm of architecture and the curriculum of architecture schools. Rapid prototyping equipment like 3D printers is becoming more and more common and allows the materialization of such designs on a model scale. But the 1:1 realization is too often just handed over to specialists, assuming that fabrication methods in full-scale architecture follow the same principles as model making. To really bridge the gap between design and fabrication, it is necessary to acquire knowledge about the real building process and the methods and tools involved.”

The authors continue to note that “The concept of the ‘digital chain’ or ‘file-to-factory’ processes has been explored by researchers and also in several teaching projects during the last few years”. Some examples of this research are listed in the references [13]. They then outline how timber structures work with CNC fabrication, in a few paragraphs that are good enough to be quoted in their entirety:

“... it is not only the digital tools used during the design phase that determine the architectural outcome of a design process. The result of the design process may be interesting in itself. However, if the designer intends to see the project realized as a close approximation to the design as possible, the limitations given by the CNC production machinery and indeed the material itself must be taken into consideration even in the early design phase. Since the beginning of industrialization, timber construction has been the standard material for prefabricated housing. Because of this background, between the nineteenth and twentieth centuries the technical development of timber production chains and machines was more advanced than any other in the building industry. Today, timber manufacturing infrastructure has changed significantly from inflexible mass production tools to an excellent level of flexible CNC-machines. Producers are relying largely on digital processes to control their computer-aided tools, but are using this potential mostly for customizing industrial processes in prefabricated housing. CAM software and CNC tools in timber construction differ from other applications in the building industry. While routers, lathes and mills were well introduced in machine engineering before they were used in building construction, CNC machines for timber construction were specifically developed for their trade and therefore match the requirements of the building industry, such as the large scale of the prefabricated panels, specific tolerances, low budgets, and high processing speed.

“The most widely used CNC machinery in the timber building industry are machines that prepare components such as beams for subsequent assembly into larger elements or panels. In general this type of CNC machinery is termed “beam processors”. In our projects we have worked with two types of CNC machines, both made by the German company Hundegger Maschinenbau GmbH. Hundegger calls the simplest of their beam processors – the Speed Cut SC1 machine – ‘an automatic cutting machine’. It was developed mainly for the rapid and precise cutting and the processing (milling, drilling, marking, and lettering) of simple wooden constructional components. The tools operate in four axes. The larger Hundegger K2 and K3 may be either 4-axis or 5-axis machines, defined by Hundegger as ‘fully automated joinery machines’. These machines make the same operations as the SC1.

“While the timber building industry’s beam processors are mainly used for mass-production, our projects, on the other hand, aimed to study the use of the same machines in the context of mass- customization so that each building component may be different but without affecting the efficiency of planning and production. The projects aimed to demonstrate the design potential of the beam processors taking the production capacities of the machines beyond their normal use and to show how contemporary fabrication technology can be reflected in design. The aim was to demonstrate for architectural practices the design possibilities when working with the production technology in mind using the capabilities of digital fabrication technology consciously in the design process. Timber construction holds a large share of the Norwegian building market, especially in housing projects, but there are hardly any architects involved in the design. Thus it was considered an important outcome of the projects that architectural practices should become aware of the industry’s possibilities for realizing new concepts in architectural design [12].”

Branko Kolarevic [14] points out in paper on digital fabrication: “Furthermore, the digital age enabled a direct digital link between what can be represented and what can be built through “file-to-factory” processes of computer numerically controlled (CNC) fabrication. There is an unprecedented directness with which digital design information can be used in the construction of buildings. The consequence is that architects are becoming much more directly involved in the fabrication, as they can efficiently create the information that is translated directly into the control data that drives the digital fabrication equipment. A growing number of successfully completed projects, which vary considerably in size and budgets, demonstrate that digital fabrication can offer productive opportunities within schedule and budget frameworks that need not be extraordinary. ... It is this digitally-based convergence of representation and production processes that represents the most important opportunity for a profound transformation of architecture as a profession and, by extension, of the entire building industry.”

2.3 Slotting

In 1951, Charles and Ray Eames released “House of cards”, which ended in a wide range of design classics [15]. Despite being made of paper, the House of Cards is an almost perfect metaphor to the material logic upon which our approach for this second phase of the log project is based. We are now interested in the slotting together of cross-laminated timber panels, in the act of slotting one such panel into another, and in the spaces that can be manufactured and constructed this way. We are also interested in finding ways of broadening this concept of slotting to internalise within the scheme other congruent ideas at different scales: the slotting together of the laminate boards that make up the CLT, the slotted joints prevalent within traditional timber construction, the slotting of spaces or volumes, and finally the slotting of entire programs: a kitchen slotting into a bathroom, a terrace slotting into a bedroom, and so on.

We are particularly interested in this concept of architectural slotting of two- and three-dimensional elements as it provides an excellent starting point for working within the exciting and reasonably new- fangled framework of design ingenuity made possible by contemporary computer-based fabrication techniques. We enjoy the hi-tech/low-tech approach made possible by digital fabrication: the fact that it is now possible to transfer designs – built upon thousands of years of experience from wood architecture – made on a computer to computer-controlled machinery that then creates actual building components. This is the “file to factory” process at the heart of this phase of the project. To quote Lisa Iwamoto [16] such a process “not only enables architects to realize projects featuring complex or double-curved geometries, but also liberates architects from a dependence on off-the-shelf building components, enabling projects of previously unimaginable complexity.”

We have focused our initial research on slotting in architecture on a loose chronology of six main areas of interest that describe a trajectory through the history of building in wood: traditional japanese temples, log houses, contemporary architecture examples, pavilions, computational/digital manufacturing design projects, and CNC buildings.

3. The Zembla project in Kalmar, Sweden

The Zembla project is a post-sustainable file-to-factory-produced timber ground-scraper that redefines the urban/rural edge of Kalmar, Sweden, soaring high above ground and water, suggesting a new way of life through a new way of making city-sized buildings for the future. An example view of the project is shown in Fig. 3.

Fig. 3. Illustration of the Zembla project in Kalmar, Sweden. Here waterfront anchoring is appearing. Living units are placed in into the grid. Each unit is unique and is customised both to its weather and topological conditions within the grid, but can also be uniquely adjusted for the usage itself, i.e. from the density of the rooms to the creation of the furniture and even crockery.

The project points out the ground datum as a counterpoint to the necessary further densification of our urban nodes. Having the structure undulate across the topography and touching the ground in as few places as possible uses the dichotomy between landscape and urbanism to allow the project to reverse today’s migration patterns, bringing the city to the people living in less densified areas. It redefines the notion of sprawl, turning it into a progressive tactics for linking the city fabric to rural areas.

The earth contains about one trillion tonnes of wood, which grows at a rate of ten billion tonnes per year. As an abundant, carbon-neutral or even carbon-negative renewable resource, timber is the only readily available building material that stores carbon dioxide, minimises or eliminates its carbon footprint, and hence is truly post sustainable.

3.1 The digital process

The digital process has been described in Part 1 of the companion paper [1]. Here some of the basics are pointed out and put in its context.

Digital manufacturing makes it possible for standard building materials to be turned into non-standard architecture. File-to-factory strategies can assist this operation. This project is an example of how such digital tools could be applied to give Kalmar a new dense-yet-light urban fringe.

Add to this digitally controlled processing of a high-tech material today’s possibilities for having different systems communicate with each other, and we end up with a highly flexible process where computer-aided manufacturing (CAM) and computer numerically controlled (CNC) technologies are linked to parametric design software and, possibly, even live-fed contextual data from the site in question. This would form a file-to-factory operation that would make it possible to manufacture individualised building components in a highly economical manner. The various parts would not only be adapted to fit perfectly together, forming a network of interlinked relationships, but would also acquire a new, time-based property: as it is analysed and tested before being inserted into the scheme, the component adapts to analytical data; once it has been installed, if fitted with a sensor, it can continuously feed data back into the system, reporting on its on status within the framework of the building. Such a data-to-site feedback loop would not only maximise efficiency throughout the building process, but also increase the building's performance while adding interesting possibilities of

7 influencing the architectural palette during the extended design phase over time. New fabrication methods give rise to new structures, new ways of using those structures, new architectures.

Prefabrication is often referred to as “architecture’s oldest new idea” – and for good reason. Not only has it been around for thousands of years, it has also been touted as the next big thing in architecture for about as long. CNC technology allows us to fabricate this building on site using a “nowfab” rather than a prefab system. Timber is a fitting material for this now-fabrication. Nowfabing mass- customised living units reduces construction times and minimises waste, thus decreasing the building’s ecological footprint.

This scheme for Kalmar does not sit easily within a common typology. No structure of its kind has ever been built. Non-standard architectures call for non-standard ideas about how to use strategies such as mass customisation in the process, though, crucially, it does not necessarily call for non- standard building materials or building processes. While its expression, program, manufacturing process, and design approach are all atypical, it is still a building that can be made by everyday builders from perfectly normal engineered wood.

3.2 Grid development

The grid was used as a tool to develop the form of the project through a certain amount of automation. Seed points (where the grid touches the ground) were chosen on the site based on criteria. The grid then seeks to create the optimal arrangement between this points based on contextual, structural and architectural inputs. Once this base grid is set, it become both the transportation and infrastructural nervous system of the project. Living units are then slotted into the gaps in the grid based on a second set of criteria. (I.e. amount of light needed below the grid, type/size of apartments needed, etc.)

The grid was developed and scripted using grasshopper. We worked on creating a logical strategy that can be used to create the grid in a number of basic steps. Part of the reason for these steps is the ability to then transfer it to other sites globally and let the script or algorithm react to local contexts. Different data can then be input into the algorithm in order to adjust for those specific briefs. Perhaps the most important step is the first one, as this establishes the nodal points at which the structure will touch the ground, as this creates the limits to the structures, the connection across the sites, what areas will be opened up as green spaces and so on.

The four phases of the grid development (a) establishing the nodal points, (b) laying out the typographical grid, (c) the process of circulation and (d) the commercial/programmatic phasing are shown in Figures 4a – 4d.

(a) (b)

Fig. 4. The grid development: (a) establishing the nodal points; (b) laying out the typographical grid; (c) the process of circulation; and (d) the commercial/programmatic phasing.

3.3 The complete scheme of the Zembla project

The characteristics of the scheme of the Zembla project as shown in Fig. 5 and Fig. 6 are as follows:

1. Concept: Zembla is a ground-scraper – a horizontal skyscraper city based on a massive timber grid-shell inside of which wooden living units plug in. 2. Urbanism – Linking the waterfront to the edge of the city of Kalmar, the scheme redefines the notion of sprawl, intensifying the suburban condition. 3. Materiality: Swedish engineered timber is used throughout: Massive CLT beams meet panels made from massive wood – beautiful and sustainable. 4. Sustainability: Timber is the only existing building material that is not only fully renewable, but capable of turning the entire building into a CO2 store. 5. Nowfab: Using an advamced file-to-factory methodology, each individual member is cut to size on site using CNC routers, not prefab (prefabrication), but nowfab (now fabrication). 6. Program: Public squares are created where the structure touches the ground; the grid provides both interior and exterior walkways and cycle paths. 7. Scalability: The project is built in phases, with more living units being added as and when needed, flexibility is key: the grid can expand and contract.

8. Vernacular: The wooden living units are paited with traditional “Falu röd”, while the gridshell is a contrasting white: the Swedish cottage updated. 9. Site: The ground is left virually untouched as the grid hovers above the site, protecting the green landscape below while supporting life above. 10. Structure: The living units are slotted together and hung from a network of catenary arches making up the oversized gridshell structure.

Fig. 5. Physical model of the Zembla project (detail).

Fig. 6. Longitudinal section of the Zembla project (north → south). From left to right: (i) access point in the area of existing buildings; (ii) main road; (iii) living units; (iv) grid-shell; (v) piled foundations; (vi) undulating organisation; (vii) sea-front pathway; and (viii) boat moorings.

The different parts of the completed scheme of the Zembla project from the site to the singular elements are shown in Fig. 7 in an exploded view. This diagram shows how a rough breakdown on how the structure goes together. From the top can seen the single components of a living unit, walls, window etc. would be slotted together. These single units then slot into a larger structural element that fits inside a single grid-space. It can be seen how this is now connected to grid-shell (and now the equivalent of a street). This then slots into the more localised community and finally into the scheme as a whole. As can be seen in the previous diagrams, Figures 4c - 4d, these would not just be living units, but a mix of living, commercial, public, light industrial and all the variety’s of program one need to make a local community flourish.

Fig. 7. Exploded scheme from site to singular elements. 12

Some typical views of the Zembla project from different perspectives in addition to Figure 3 are shown in Figures 8 and 9. The project hovers above existing contexts, and density is controlled to allow natural light on the landscape below. These also free up the landscape below to the public, the greenspace becomes almost as big as the project itself.

Fig. 8. Gravity-defying moment

Fig. 9. Ground condition.

3.4 Construction systems and interconnections

An overview of the grid structure, circulation deck and infrastructure is illustrated in Fig. 10 with the description of the different parts given in the caption of the figure. The below is a breakdown on how the grid-shell structure and circulation deck becomes the nervous system and streetscape for the entire project. It is how people access their homes and shops. The construction method is listed below, the logic is a gain based of the grid-space as a base reference, so that everything else can be base on top of it algorithmically, and therefore create a degree of automation when applying it to other areas of the grid.

i ii iii iv v vi vii viii ix

Fig. 10. Overview of the construction systems. From top to bottom: (i) living unit central structure; (ii) grid intersection space; (iii) pedestrian walkway; (iv) walkway handrail; (v) walkway infill panels; (vi) walkway structure; (vii) infrastructure/services; (viii) main grid structure; and (ix) joint elements.

The different types of construction system are described in more detail in Figs. 11-14.

Fig. 11. Main grid structure: The main structure of the grid is based on the timber bridge systems developed by Martinsons. These structural elements are based on their box beam model, allowing the construction of structural spans up to 30 m. The joints between each grid element will take a significant amount of load and as such are constructed using the solid beam model.

Fig. 12. Secondary structure: The secondary structure of the grid forms an occupiable void above the main structure for infrastructure and services, and supports a deck level for pedestrian and cyclist circulation. The secondary grid structure is based on the post and beam systems developed by Moelven. This system allows for an open structural skeleton, allowing for easy maintenance of the services level.

Fig. 13. Circulation deck: The circulation deck is the upper most level of the grid structure. It allows pedestrians and cyclists to navigate the grid freely and easily. The routes form the minor circulation routes between living units. Main circulation routes are formed by specifically infilled grid cells which form wide circulation highways.

Fig. 14. Infrastructure and services: The infrastructure and services of the grid are carried above the main structure in the void created by the secondary structure. This void allows for the construction of simple services networks that are easily accessed for maintenance, repairs and upgrades.

3.5 Living units

The living units are placed in into the grid. Each unit is unique and is customised both to its weather and topological conditions within the grid, but can also be uniquely adjusted for the usage itself, i.e. from the density of the rooms to the creation of your furniture and even crockery. An example of a living unit is illustrated in Fig. 15.

Fig. 15. An example of a living unit.

The structure of the living unit is based around a primary structure of 1.2 m thick walls that have been articulated to take the structure load of the rest of the floor plates. There is a portal frame at the top that supports the facade system. It is a handing facade system. Everything is hung from the top portal frame. The built up of the living unit is illustrated in Fig. 16. We used slotting as the base tectonic/design driver, from the macro to the micro scale. Living units get slotted into the grid. The living unit walls are slotted together, the windows then get slotted into these walls and so on.

(a) Main structural cross: In this case the (b) Floor plates are inserted into the main cross circulation is carved into it in order to maximise giving stability to the cross. A portal frame is floor space. added to the top of the structure.

Fig. 16. Living unit structure.

4. Summary A “file-to-factory” process of computer technology, described in a companion paper, has been applied as a proposal for establishing a new residential area in the urban-rural edge of the city of Kalmar, Sweden, a proposal called Zembla. The basics of grid development and slotting as parts of the file-to- factory process are discussed for the Zembla project. The four phases of grid development concerning establishing the nodal points, laying out the typographical grid, the process of circulation and the commercial/programmatic phasing are illustrated. The characteristics involved in the scheme of this type of project are presented. The different construction systems of the project concerning the living

17 unit central structure, the grid intersection space, the pedestrian walkway, the walkway handrail, the walkway infill panels, the walkway structure, the infrastructure/services, the main grid structure and the joint elements are briefly discussed. Also, an example of the living units, and their structural features, that are placed in into the grid and hung from the top frame is illustrated.

Acknowledgement The authors would like to express their sincere appreciation for the financial support from the Regional Council of Västerbotten, the County Administrative Board in Norrbotten, and the European Union: European Regional Development Fund – Regional Structural Fund and Interregional Programmes.

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