PLASTICS in Architecture and Construction

9



1

The development of plastic architecture

Plastics are high-performance materials with very different properties and can be found in the world around us in many different forms and applications. One of the areas where plastics are used is architecture. Building with plastics is an experi­ mental and highly interesting specialist area of architecture. In this chapter we will examine some of the most important developments in the history of plastics in architecture.

Plastics are a comparatively recent material, despite the fact that the natural precursor of today’s modern material – natural rubber, harvested from the gum tree – has been known for over 500 years. Today plastics are generally artificially produced. The motivation behind the development of the modern material dates back to the period of early industrialisation and the need for an artificially producible alternative to the highly sought-after but expensive natural raw material.

Intensive research activities soon sprang up to find a cost-effective and artificial material capable of replacing the natural product that could be syntheti­cally manu­factured in large quantities. The German name for plastics, “Kunststoff”, meaning literally “artificial material”, became more widely known with the publication of a journal of the same name in 1911. Beside the synthetic manufacture of ­materials, one of the most important motivations for the development of plastics was to be able to optimise special material properties.

A significant number of the plastics used today in construction had already 1.1

been developed by the end of the 1940s. These include, for example, ­polyvinyl chloride (PVC), polymethacrylate (PMMA), polystyrene (PS), polyethylene (PE), polyurethane (PUR) and polytetrafluoroethylene (PTFE). Beside these basic types, there are numerous different modifications with special formulas designed by manufacturers to serve specific purposes. Plastics, and in particular fibre-re­ inforced plastics, make it fundamentally possible to fashion a material for a particular application. For this reason the improvement or rather optimisation of material properties focuses less on the creation of new materials than on the ­further development of existing materials as well as their combination in the form of composite materials.

The foundation for high-performance composite materials was laid in the 1940s with the development of polyester resin in combination with the industrialscale production of glass fibres. This concept for a composite material was quickly adopted for a variety of uses, for example for the construction of aeroplanes, boats and vehicles, and the new material rapidly established itself in many different industrial fields.

9



1

The development of plastic architecture

Plastics are high-performance materials with very different properties and can be found in the world around us in many different forms and applications. One of the areas where plastics are used is architecture. Building with plastics is an experi­ mental and highly interesting specialist area of architecture. In this chapter we will examine some of the most important developments in the history of plastics in architecture.

Plastics are a comparatively recent material, despite the fact that the natural precursor of today’s modern material – natural rubber, harvested from the gum tree – has been known for over 500 years. Today plastics are generally artificially produced. The motivation behind the development of the modern material dates back to the period of early industrialisation and the need for an artificially producible alternative to the highly sought-after but expensive natural raw material.

Intensive research activities soon sprang up to find a cost-effective and artificial material capable of replacing the natural product that could be syntheti­cally manu­factured in large quantities. The German name for plastics, “Kunststoff”, meaning literally “artificial material”, became more widely known with the publication of a journal of the same name in 1911. Beside the synthetic manufacture of ­materials, one of the most important motivations for the development of plastics was to be able to optimise special material properties.

A significant number of the plastics used today in construction had already 1.1

been developed by the end of the 1940s. These include, for example, ­polyvinyl chloride (PVC), polymethacrylate (PMMA), polystyrene (PS), polyethylene (PE), polyurethane (PUR) and polytetrafluoroethylene (PTFE). Beside these basic types, there are numerous different modifications with special formulas designed by manufacturers to serve specific purposes. Plastics, and in particular fibre-re­ inforced plastics, make it fundamentally possible to fashion a material for a particular application. For this reason the improvement or rather optimisation of material properties focuses less on the creation of new materials than on the ­further development of existing materials as well as their combination in the form of composite materials.

The foundation for high-performance composite materials was laid in the 1940s with the development of polyester resin in combination with the industrialscale production of glass fibres. This concept for a composite material was quickly adopted for a variety of uses, for example for the construction of aeroplanes, boats and vehicles, and the new material rapidly established itself in many different industrial fields.

10

INTRODUCTION

THE DEVELOPMENT OF PLASTIC ARCHITECTURE

1.1 Cover of the first issue of the journal “Kunststoffe”, published on 1 January 1911.

André Coulon together with the engineer Yves Magnant developed a series of

1.2 Geodesic dome made of GRP elements, R. Buckminster Fuller, 1954. 1.3 Mobile hotel cabin,

dwelling units and a building out of the new material. Known as the “snail shell

I. Schein, R.-A. Coulon, Y. Magnant, 1956. The plastic cells made of GRP were conceived as modular units and optimised for transportation.

house” because of its geometry, it was constructed out of a combination of flat and uniaxially curved GRP sandwich panels with GRP stiffening ribs. The organically

1.1

formed sanitary cells of the snail shell house and the mobile hotel cabin developed

1.2

in the same year gave an indication of the design potential of the new material.

An important step was made with the development of building elements 1.4

as sandwich constructions in which fibre-reinforced plastic was combined with PUR insulation materials. The use of this technology, in which an insulating core ­material is sandwiched between two thin GRP layers, made it possible to create lightweight and simultaneously rigid sandwich elements which were ideally suited for self-supporting building skins. The “Monsanto House of the Future” (architects: Richard Hamilton and Marvin Goody, engineer: Albert Dietz, USA, 1957) made use of this principle. It was the first plastic house to be fully developed for mass production. Although it was destined for industrial production, only the prototype was realised. Nevertheless, the building was effective in demonstrating the structural, architectonic and thermal performance of the plastic constructions and, above all, because of its futuristic formal language, the design possibilities of the

1.3

new material.

As a result, interest in plastic houses grew rapidly around the world. Engineers and architects researched the material and numerous projects followed that ex­ploited its benefits. The 1960s in particular were characterised by a variety of architectural experiments aimed at finding a form appropriate to the material. The use of new materials also brought forth a new formal language. In many houses made of plastic, rounded forms and curved building elements are to be found in ­variously pronounced forms. In addition to a general predilection for rounded forms in the 1960s, the use of curved building elements can also be attributed to The specific properties of fibre-reinforced plastics, in particular their light weight, good weather resistance and excellent forming characteristics in con-

ing, folding or creasing the thin material of the building skin to stabilise its form.

junction with comparatively high strength, make them of particular interest for

The ability to prefabricate elements and the low level of maintenance required

architectural applications. The first projects for buildings made of plastic were

for ­buildings made of plastic, also played a decisive role. One of the high points

developed as far back as the 1940s. The buildings were conceived as a serially

in plastic architecture was the IKA (International Plastic Housing Exhibition) in

producible system of prefabricated elements in order to compensate for the lack of conventional building materials after the end of the Second World War. These projects, however, never made it into production.

After the war various plastics manufacturers attempted to find new markets 1.2

1.5

Lüdenscheid, Germany, which from 1971 onwards featured a series of prototypes for family dwellings and holiday homes, including the “Futuro” (architect: Matti ­Suuronen, engineer: Yrjö Ronkka), “Rondo” (architects: Casoni & Casoni, engineer: René Walther), “fg 2000” (architect: Wolfgang Feierbach, engineer: Gerhard

in the realm of architecture. Pioneering architects and engineers began to experi-

­Dietrich, Carsten Langlie) and “Bulle Six Coques” (six-shell bubble house, archi-

ment with the new material. The first use of glass fibre-reinforced plastics (GRP) in

tect: Jean Benjamin Maneval, engineer: Yves Magnant).

building constructions was in 1954 for military radar domes. The geodesic domes

The technical requirements of mass production were often the point of depar-

devised by Richard Buckminster Fuller were an ideal application for the light,

ture for planning deliberations, although the prototypes themselves were typically

translucent and electromagnetically permeable GRP material.

1.3

the desire to lend the comparatively flexible material greater stiffness by curv-

made laboriously by hand. The intention of the designers was to use existing manu­

In contrast to thermoplastics, construction elements made of fibre-reinforced

facturing methods for the cost-effective production of plastic houses of a high

polyester resin are easy to produce without the need for complex machinery and

technical standard. In 1973, the Darmstadt Institute for Building with Plastics (IBK)

are therefore ideally suited for the manufacture of prototypes. The first residen-

published a comprehensive report that documented 232 international concepts

tial building made of plastic was built in 1956 in France. In collaboration with the

and realised projects. The majority of the projects never made it beyond the proto-

French chemical company Camus et Cie., the architects Ionel Schein and René-

type; only 38 % of the examples shown were built more than once, mostly in small

11

10

INTRODUCTION

THE DEVELOPMENT OF PLASTIC ARCHITECTURE

1.1 Cover of the first issue of the journal “Kunststoffe”, published on 1 January 1911.

André Coulon together with the engineer Yves Magnant developed a series of

1.2 Geodesic dome made of GRP elements, R. Buckminster Fuller, 1954. 1.3 Mobile hotel cabin,

dwelling units and a building out of the new material. Known as the “snail shell

I. Schein, R.-A. Coulon, Y. Magnant, 1956. The plastic cells made of GRP were conceived as modular units and optimised for transportation.

house” because of its geometry, it was constructed out of a combination of flat and uniaxially curved GRP sandwich panels with GRP stiffening ribs. The organically

1.1

formed sanitary cells of the snail shell house and the mobile hotel cabin developed

1.2

in the same year gave an indication of the design potential of the new material.

An important step was made with the development of building elements 1.4

as sandwich constructions in which fibre-reinforced plastic was combined with PUR insulation materials. The use of this technology, in which an insulating core ­material is sandwiched between two thin GRP layers, made it possible to create lightweight and simultaneously rigid sandwich elements which were ideally suited for self-supporting building skins. The “Monsanto House of the Future” (architects: Richard Hamilton and Marvin Goody, engineer: Albert Dietz, USA, 1957) made use of this principle. It was the first plastic house to be fully developed for mass production. Although it was destined for industrial production, only the prototype was realised. Nevertheless, the building was effective in demonstrating the structural, architectonic and thermal performance of the plastic constructions and, above all, because of its futuristic formal language, the design possibilities of the

1.3

new material.

As a result, interest in plastic houses grew rapidly around the world. Engineers and architects researched the material and numerous projects followed that ex­ploited its benefits. The 1960s in particular were characterised by a variety of architectural experiments aimed at finding a form appropriate to the material. The use of new materials also brought forth a new formal language. In many houses made of plastic, rounded forms and curved building elements are to be found in ­variously pronounced forms. In addition to a general predilection for rounded forms in the 1960s, the use of curved building elements can also be attributed to The specific properties of fibre-reinforced plastics, in particular their light weight, good weather resistance and excellent forming characteristics in con-

ing, folding or creasing the thin material of the building skin to stabilise its form.

junction with comparatively high strength, make them of particular interest for

The ability to prefabricate elements and the low level of maintenance required

architectural applications. The first projects for buildings made of plastic were

for ­buildings made of plastic, also played a decisive role. One of the high points

developed as far back as the 1940s. The buildings were conceived as a serially

in plastic architecture was the IKA (International Plastic Housing Exhibition) in

producible system of prefabricated elements in order to compensate for the lack of conventional building materials after the end of the Second World War. These projects, however, never made it into production.

After the war various plastics manufacturers attempted to find new markets 1.2

1.5

Lüdenscheid, Germany, which from 1971 onwards featured a series of prototypes for family dwellings and holiday homes, including the “Futuro” (architect: Matti ­Suuronen, engineer: Yrjö Ronkka), “Rondo” (architects: Casoni & Casoni, engineer: René Walther), “fg 2000” (architect: Wolfgang Feierbach, engineer: Gerhard

in the realm of architecture. Pioneering architects and engineers began to experi-

­Dietrich, Carsten Langlie) and “Bulle Six Coques” (six-shell bubble house, archi-

ment with the new material. The first use of glass fibre-reinforced plastics (GRP) in

tect: Jean Benjamin Maneval, engineer: Yves Magnant).

building constructions was in 1954 for military radar domes. The geodesic domes

The technical requirements of mass production were often the point of depar-

devised by Richard Buckminster Fuller were an ideal application for the light,

ture for planning deliberations, although the prototypes themselves were typically

translucent and electromagnetically permeable GRP material.

1.3

the desire to lend the comparatively flexible material greater stiffness by curv-

made laboriously by hand. The intention of the designers was to use existing manu­

In contrast to thermoplastics, construction elements made of fibre-reinforced

facturing methods for the cost-effective production of plastic houses of a high

polyester resin are easy to produce without the need for complex machinery and

technical standard. In 1973, the Darmstadt Institute for Building with Plastics (IBK)

are therefore ideally suited for the manufacture of prototypes. The first residen-

published a comprehensive report that documented 232 international concepts

tial building made of plastic was built in 1956 in France. In collaboration with the

and realised projects. The majority of the projects never made it beyond the proto-

French chemical company Camus et Cie., the architects Ionel Schein and René-

type; only 38 % of the examples shown were built more than once, mostly in small

11

12

INTRODUCTION

THE DEVELOPMENT OF PLASTIC ARCHITECTURE

quantities. One exception was the so-called “Polyvilla”, a rectangular hybrid con-

1.4 The “Monsanto House of the Future”, R. Hamilton, M. Goody, A. Dietz, 1957, was the first plastic ­house to be conceived for mass production. 1.5 International Plastic Housing Exhibition, IKA Lüdenscheid, Germany, 1971. Left “Futuro” (M. Suuronen, Y. Ronkka), foreground “Bulle Six Coques” (J. B. Maneval, Y. Magnant), right “Rondo” (Casoni & Casoni, R. Walther).

struction made of lightweight concrete and plastic with a traditional form, which was built over 500 times within a period of ten years. In the concluding chapter, the

13

report predicted a future for the industrial mass production of plastic houses but recognised that the resulting standardisation would be problematic for marketing them as private houses.

1.4

1.5

The plastic houses that were realised proved that plastics were fundamentally suitable for use in architecture and that in terms of structural stability, thermal performance and durability, they could be used in place of conventional materials.

Their use was restricted primarily to single-storey buildings. Beside the production of entire buildings that were delivered as prefabricated products equipped with integrated fittings, further applications included individual components made 1.6

of plastic, for example sandwich panel façade elements, prefabricated ­sanitary cells and roofing elements. The experimental test structures from this period addressed many key considerations and together made a significant contribution to the future of plastic architecture.

The structural potential and technical performance of fibre-reinforced plastics was of particular use for wide-span roof structures. A series of engineers devel-

1.8

1.7

ponents but only rarely and in special circumstances were entire buildings realised in plastic.

In recent years, plastics have begun to experience a renaissance in the field of

oped outstanding concepts for high-performance structures. One example is the

architecture and construction. In addition to building elements and components

“Les échanges” Pavilion by the Swiss engineer Heinz Hossdorf presented at the

for technical and constructional installations, for example piping and insulation,

Expo 1964 in Lausanne, a pre-stressed construction consisting of a grid of multi-

plastics are increasingly being used as high-performance materials for supporting

ple umbrella-like elements made of 3 mm thick GRP sections. The modular shell

structures and building skins. A distinction is drawn here between loadbearing and

constructions by the French engineer Stéphane du Château are a further example

non-loadbearing building elements. Non-loadbearing applications are, for exam-

of wide-span GRP structures. The segmented dome shell of the market hall roof in

ple, interior fittings and façade cladding in particular. Where sufficient quantities

Argenteuil, made of 30 prefabricated 6 mm thick GRP shell elements on an under-

are required, it is possible to manufacture extremely complex, geometric preci-

lying lightweight steel construction, spanned a diameter of 30 m.

sion elements using highly automated techniques. The use of plastics for building

The pioneering buildings of the 1950s to 1970s did not, however, lead to the

skins depends on the thermal and physical characteristics required. For loadbear-

widespread adoption of housing made of plastic. By 1973, not a single one of the

ing structures, fibre-reinforced plastics are still the most commonly used option.

purely plastic houses had been mass-produced. The great expectations that the

Application areas include supporting structures for buildings as well as industrial

designers and industry had placed in the new material remained unfulfilled and

architecture and engineering structures.

the envisaged demand failed to materialise. The reasons for this are manifold: for example, the oil crisis in the 1970s led to a considerable rise in the price of plastics.

Special building elements with complex geometries are another area where plastics are appropriate. While the manufacture of moulds for such materials usu-

However, the interruption in the development of plastic architecture cannot solely

ally requires a high degree of manual skilled labour at a corresponding cost, plas-

be attributed to the oil crisis. Although the forms were appropriate to the material,

tics make it possible to produce highly differentiated building elements in large

their unconventional looks and living concepts were not embraced by the public.

quantities at exacting tolerances. This is particularly relevant for modular systems.

Very few clients were willing to realise the dream of their own home in the form of

The low self-weight of the material is a particular advantage in terms of transpor-

an industrially mass-produced plastic house, particularly as they were not much

tation. The comparatively high investment required for fabrication is compensated

cheaper than a conventional house. The low level of demand in turn inhibited their

for by the ability to produce large quantities. In addition, plastics have long played

mass production, which would have led to a reduction in costs and greater eco-

an important role in construction maintenance, most notably carbon fibre-rein-

nomic competitiveness compared with conventional prefabricated houses.

forced plastics for the repair and strengthening of concrete structures.

A further problem that ultimately led to the premature cessation of develop-

Surprisingly, plastics are all too often regarded as a lower-quality substitute

ment activities was the difficulty of obtaining building control approval: several

material when, in fact, the reverse is true: plastics are high-tech products. An ade-

prototypes exhibited physical defects (mould etc.) and poor fire safety charac-

quate appreciation of plastics is, however, essential in order to best exploit their

teristics. Nevertheless, a series of different plastic buildings, such as the “Futuro”

diverse, excellent properties and for the emergence of innovative plastic architec-

or the “fg 2000” have become milestones in the history of modern architecture.

ture. Of vital importance too is the search for forms of construction that are appro-

After this period, plastics were still used in a variety of ways for individual com-

priate to the material. In this respect there is still much room for development.

12

INTRODUCTION

THE DEVELOPMENT OF PLASTIC ARCHITECTURE

quantities. One exception was the so-called “Polyvilla”, a rectangular hybrid con-

1.4 The “Monsanto House of the Future”, R. Hamilton, M. Goody, A. Dietz, 1957, was the first plastic ­house to be conceived for mass production. 1.5 International Plastic Housing Exhibition, IKA Lüdenscheid, Germany, 1971. Left “Futuro” (M. Suuronen, Y. Ronkka), foreground “Bulle Six Coques” (J. B. Maneval, Y. Magnant), right “Rondo” (Casoni & Casoni, R. Walther).

struction made of lightweight concrete and plastic with a traditional form, which was built over 500 times within a period of ten years. In the concluding chapter, the

13

report predicted a future for the industrial mass production of plastic houses but recognised that the resulting standardisation would be problematic for marketing them as private houses.

1.4

1.5

The plastic houses that were realised proved that plastics were fundamentally suitable for use in architecture and that in terms of structural stability, thermal performance and durability, they could be used in place of conventional materials.

Their use was restricted primarily to single-storey buildings. Beside the production of entire buildings that were delivered as prefabricated products equipped with integrated fittings, further applications included individual components made 1.6

of plastic, for example sandwich panel façade elements, prefabricated ­sanitary cells and roofing elements. The experimental test structures from this period addressed many key considerations and together made a significant contribution to the future of plastic architecture.

The structural potential and technical performance of fibre-reinforced plastics was of particular use for wide-span roof structures. A series of engineers devel-

1.8

1.7

ponents but only rarely and in special circumstances were entire buildings realised in plastic.

In recent years, plastics have begun to experience a renaissance in the field of

oped outstanding concepts for high-performance structures. One example is the

architecture and construction. In addition to building elements and components

“Les échanges” Pavilion by the Swiss engineer Heinz Hossdorf presented at the

for technical and constructional installations, for example piping and insulation,

Expo 1964 in Lausanne, a pre-stressed construction consisting of a grid of multi-

plastics are increasingly being used as high-performance materials for supporting

ple umbrella-like elements made of 3 mm thick GRP sections. The modular shell

structures and building skins. A distinction is drawn here between loadbearing and

constructions by the French engineer Stéphane du Château are a further example

non-loadbearing building elements. Non-loadbearing applications are, for exam-

of wide-span GRP structures. The segmented dome shell of the market hall roof in

ple, interior fittings and façade cladding in particular. Where sufficient quantities

Argenteuil, made of 30 prefabricated 6 mm thick GRP shell elements on an under-

are required, it is possible to manufacture extremely complex, geometric preci-

lying lightweight steel construction, spanned a diameter of 30 m.

sion elements using highly automated techniques. The use of plastics for building

The pioneering buildings of the 1950s to 1970s did not, however, lead to the

skins depends on the thermal and physical characteristics required. For loadbear-

widespread adoption of housing made of plastic. By 1973, not a single one of the

ing structures, fibre-reinforced plastics are still the most commonly used option.

purely plastic houses had been mass-produced. The great expectations that the

Application areas include supporting structures for buildings as well as industrial

designers and industry had placed in the new material remained unfulfilled and

architecture and engineering structures.

the envisaged demand failed to materialise. The reasons for this are manifold: for example, the oil crisis in the 1970s led to a considerable rise in the price of plastics.

Special building elements with complex geometries are another area where plastics are appropriate. While the manufacture of moulds for such materials usu-

However, the interruption in the development of plastic architecture cannot solely

ally requires a high degree of manual skilled labour at a corresponding cost, plas-

be attributed to the oil crisis. Although the forms were appropriate to the material,

tics make it possible to produce highly differentiated building elements in large

their unconventional looks and living concepts were not embraced by the public.

quantities at exacting tolerances. This is particularly relevant for modular systems.

Very few clients were willing to realise the dream of their own home in the form of

The low self-weight of the material is a particular advantage in terms of transpor-

an industrially mass-produced plastic house, particularly as they were not much

tation. The comparatively high investment required for fabrication is compensated

cheaper than a conventional house. The low level of demand in turn inhibited their

for by the ability to produce large quantities. In addition, plastics have long played

mass production, which would have led to a reduction in costs and greater eco-

an important role in construction maintenance, most notably carbon fibre-rein-

nomic competitiveness compared with conventional prefabricated houses.

forced plastics for the repair and strengthening of concrete structures.

A further problem that ultimately led to the premature cessation of develop-

Surprisingly, plastics are all too often regarded as a lower-quality substitute

ment activities was the difficulty of obtaining building control approval: several

material when, in fact, the reverse is true: plastics are high-tech products. An ade-

prototypes exhibited physical defects (mould etc.) and poor fire safety charac-

quate appreciation of plastics is, however, essential in order to best exploit their

teristics. Nevertheless, a series of different plastic buildings, such as the “Futuro”

diverse, excellent properties and for the emergence of innovative plastic architec-

or the “fg 2000” have become milestones in the history of modern architecture.

ture. Of vital importance too is the search for forms of construction that are appro-

After this period, plastics were still used in a variety of ways for individual com-

priate to the material. In this respect there is still much room for development.

14

15

INTRODUCTION

2

1.6 Modular plastic façade made of prefabricated sandwich elements. 1.7 Market hall, Argenteuil near Paris, S. du Château, 1967. The dome measuring 30 m in diameter consists of 30 prefabricated 6 mm thick GrP shell elements mounted on a supporting tubular steel construction. 1.8 “Les échanges” Pavilion, Expo Lausanne, H. Hossdorf, 1964. A modular roof structure made of GrP hyperbolic paraboloid (hypar) surfaces, bonded to a steel frame and pre-stressed.

1.6

maTerial ProPerTies of PlasTics

1.7

Plastics are a group of materials with a broad spectrum of properties that makes them predestined for numerous different applications. Plastics can be generally divided into four categories of plastics: elastomers and thermosets, which have a cross-linked molecular structures, and thermoplastics that have an uncrosslinked structure. Thermoplastic elastomers (TPE) result from a combination of thermoplastic and elastomeric components and exhibit characteristics of both groups. Depending on the degree of cross-linking, plastics can differ in terms of strength, stiffness and resistance to heat and chemicals. The performance characteristics of individual plastics are generally very specific. Nevertheless, there

1.8

are several material properties that can be used to characterise plastics in general. This chapter provides an overview of these properties where they are relevant to the field of architecture.

ForMinG CHArACTEriSTiCS AnD THE MAnUFACTUrE oF BUiLDinG ELEMEnTS An excellent property of many plastics is the ability to shape them freely, which makes plastics ideally suitable for building elements with complex geometric forms. The production of individually shaped special forms, as is often the case 2.1

in architecture, can be comparatively costly. Prototypes made of thermosetting fibre-reinforced plastics with dimensions of up to several metres can be manually manufactured, but this is comparatively labour-intensive and correspond-

2.2

ingly expensive. A number of thermoplastic materials can be shaped with the help of rapid prototyping techniques without the need for the complex manufacture of moulds. in this case, the basis for the manufacture of a three-dimensional building element is a digital model. CnC fabrication methods include, for example, 3D printing or milling. These methods are generally only suitable for elements of a limited size.

Elastomers and thermoplastics are also suitable for the manufacture of geometrically complex building elements and can be produced industrially in large quantities. The particular advantage of prefabricating elements for the building sector is that constructions can be produced and assembled regardless of weather conditions. in the case of plastics, the creation of the material and the moulding of the element are typically one and the same process. The fabrication process makes it possible to manufacture materials that can be adapted to their expected loads, for example through the localised application and embedding of reinforcement fibres in a resin matrix. Properties such as strength or stiffness can therefore be optimised as required.

14

15

INTRODUCTION

2

1.6 Modular plastic façade made of prefabricated sandwich elements. 1.7 Market hall, Argenteuil near Paris, S. du Château, 1967. The dome measuring 30 m in diameter consists of 30 prefabricated 6 mm thick GrP shell elements mounted on a supporting tubular steel construction. 1.8 “Les échanges” Pavilion, Expo Lausanne, H. Hossdorf, 1964. A modular roof structure made of GrP hyperbolic paraboloid (hypar) surfaces, bonded to a steel frame and pre-stressed.

1.6

maTerial ProPerTies of PlasTics

1.7

Plastics are a group of materials with a broad spectrum of properties that makes them predestined for numerous different applications. Plastics can be generally divided into four categories of plastics: elastomers and thermosets, which have a cross-linked molecular structures, and thermoplastics that have an uncrosslinked structure. Thermoplastic elastomers (TPE) result from a combination of thermoplastic and elastomeric components and exhibit characteristics of both groups. Depending on the degree of cross-linking, plastics can differ in terms of strength, stiffness and resistance to heat and chemicals. The performance characteristics of individual plastics are generally very specific. Nevertheless, there

1.8

are several material properties that can be used to characterise plastics in general. This chapter provides an overview of these properties where they are relevant to the field of architecture.

ForMinG CHArACTEriSTiCS AnD THE MAnUFACTUrE oF BUiLDinG ELEMEnTS An excellent property of many plastics is the ability to shape them freely, which makes plastics ideally suitable for building elements with complex geometric forms. The production of individually shaped special forms, as is often the case 2.1

in architecture, can be comparatively costly. Prototypes made of thermosetting fibre-reinforced plastics with dimensions of up to several metres can be manually manufactured, but this is comparatively labour-intensive and correspond-

2.2

ingly expensive. A number of thermoplastic materials can be shaped with the help of rapid prototyping techniques without the need for the complex manufacture of moulds. in this case, the basis for the manufacture of a three-dimensional building element is a digital model. CnC fabrication methods include, for example, 3D printing or milling. These methods are generally only suitable for elements of a limited size.

Elastomers and thermoplastics are also suitable for the manufacture of geometrically complex building elements and can be produced industrially in large quantities. The particular advantage of prefabricating elements for the building sector is that constructions can be produced and assembled regardless of weather conditions. in the case of plastics, the creation of the material and the moulding of the element are typically one and the same process. The fabrication process makes it possible to manufacture materials that can be adapted to their expected loads, for example through the localised application and embedding of reinforcement fibres in a resin matrix. Properties such as strength or stiffness can therefore be optimised as required.

24

BASICS OF PLASTICS

CHEMICAL STRUCTURE

THE CLASSiFiCATion oF PLASTiCS ACCorDinG To THEir DEGrEE oF CroSS-LinKinG

3.7 Amorphous thermoplastic: the polymer chains form a random, unordered structure. 3.8 Semicrystalline thermoplastic: randomly oriented, amorphous regions alongside regular crystalline regions.

3.9 Elastomer: amorphous tangle of polymer chains which are interconnected at larger intervals with atomic bonds. 3.10 Thermoset: amorphous polymer chains tightly cross-linked by atomic bonds.

3.11 Thermoplastic elastomer: example of a polymer blend.

Plastics are generally differentiated according to their degree of cross-linking. This classification is helpful in that fundamental material properties such as strength,

25

heat distortion temperature, workability and thermoplastic formability are directly related to the degree of cross-linking of the polymers.

3.7

3.8

3.9

3.10

With regard to the kind and degree of cross-linking, there are four groups: thermosets (also known as duromers), elastomers, thermoplastics and thermoplastic elastomers. The boundaries between them are indistinct and in some cases it 3.4

is not always clear to which group a plastic belongs. Materials with a semi-crystalline structure are uncross-linked and belong to the thermoplastics. Plastics with amorphous structures can be found in all groups and can be both uncrosslinked (thermoplastics) as well exhibit different degrees of cross-linking (thermosets, elastomers).

THERMOPLASTICS Thermoplastics are uncross-linked and consist of polymer

chains that can be linear or branched. They are heat-deformable because the polymer chains do not form atomic bonds between each other but are linked only by secondary valence forces. The process of heat deformation is repeatable. Thermoplastics can be amorphous or semi-crystalline. in the case of amorphous thermoplastics the linear or branched molecule chains are randomly oriented and tangled. Because of their brittle nature they are particularly prone to stress cracking.

Their appearance can be opaque or transparent. Amorphous thermoplastics can 3.7

be dissolved with an appropriate solvent. Examples of amorphous thermoplastics include PMMA, polystyrene (PS) and polyvinyl chloride (PVC).

Semi-crystalline thermoplastics, by contrast, exhibit at least in parts a regular three-dimensional structure to the molecule chains. The higher density of the crystalline state compared with the amorphous condition means that heat input causes the volume to expand. Semi-crystalline thermoplastics are harder and

3.8

more resistant to solvents than amorphous structures. Polyethylene (PE), polypropylene (PP) and polyamide (PA) are examples of semi-crystalline thermoplastics.

ELASTOMERS Elastomers exhibit a three-dimensional amorphous structure with

slight cross-linking that cannot be loosened through heat without the material decomposing. For this reason they cannot be heat-deformed, melted or welded.

The tangled structure of the polymer chains is the reason for its exceptional elasticity and the fact that once the stress has been removed it returns to its original 3.9

condition. EPDM and the large family of rubber materials are examples of elastomeric plastics.

3.11

24

BASICS OF PLASTICS

CHEMICAL STRUCTURE

THE CLASSiFiCATion oF PLASTiCS ACCorDinG To THEir DEGrEE oF CroSS-LinKinG

3.7 Amorphous thermoplastic: the polymer chains form a random, unordered structure. 3.8 Semicrystalline thermoplastic: randomly oriented, amorphous regions alongside regular crystalline regions.

3.9 Elastomer: amorphous tangle of polymer chains which are interconnected at larger intervals with atomic bonds. 3.10 Thermoset: amorphous polymer chains tightly cross-linked by atomic bonds.

3.11 Thermoplastic elastomer: example of a polymer blend.

Plastics are generally differentiated according to their degree of cross-linking. This classification is helpful in that fundamental material properties such as strength,

25

heat distortion temperature, workability and thermoplastic formability are directly related to the degree of cross-linking of the polymers.

3.7

3.8

3.9

3.10

With regard to the kind and degree of cross-linking, there are four groups: thermosets (also known as duromers), elastomers, thermoplastics and thermoplastic elastomers. The boundaries between them are indistinct and in some cases it 3.4

is not always clear to which group a plastic belongs. Materials with a semi-crystalline structure are uncross-linked and belong to the thermoplastics. Plastics with amorphous structures can be found in all groups and can be both uncrosslinked (thermoplastics) as well exhibit different degrees of cross-linking (thermosets, elastomers).

THERMOPLASTICS Thermoplastics are uncross-linked and consist of polymer

chains that can be linear or branched. They are heat-deformable because the polymer chains do not form atomic bonds between each other but are linked only by secondary valence forces. The process of heat deformation is repeatable. Thermoplastics can be amorphous or semi-crystalline. in the case of amorphous thermoplastics the linear or branched molecule chains are randomly oriented and tangled. Because of their brittle nature they are particularly prone to stress cracking.

Their appearance can be opaque or transparent. Amorphous thermoplastics can 3.7

be dissolved with an appropriate solvent. Examples of amorphous thermoplastics include PMMA, polystyrene (PS) and polyvinyl chloride (PVC).

Semi-crystalline thermoplastics, by contrast, exhibit at least in parts a regular three-dimensional structure to the molecule chains. The higher density of the crystalline state compared with the amorphous condition means that heat input causes the volume to expand. Semi-crystalline thermoplastics are harder and

3.8

more resistant to solvents than amorphous structures. Polyethylene (PE), polypropylene (PP) and polyamide (PA) are examples of semi-crystalline thermoplastics.

ELASTOMERS Elastomers exhibit a three-dimensional amorphous structure with

slight cross-linking that cannot be loosened through heat without the material decomposing. For this reason they cannot be heat-deformed, melted or welded.

The tangled structure of the polymer chains is the reason for its exceptional elasticity and the fact that once the stress has been removed it returns to its original 3.9

condition. EPDM and the large family of rubber materials are examples of elastomeric plastics.

3.11

30

PLASTICS AND THEIR MANUFACTURE

ELASTOMERS

4.1 The use of plastics in Germany, 2007.

4.4 EPDM sealing profiles.

4.2 The applications of plastics in construction in Germany, 2007. 4.3 Acronyms for plastics according to Din En iSo 1043-1 (basic polymers) and Din iSo 1629 (rubbers and latices).

4.1

4.5 Test specimen for determining the hardness of plastics according to the

Shore classification.

4.2 Electronics 7.4 % Furniture 3.8 % Household products 2.9 % Agriculture 2.5 % Medicine 1.7 %

31

4.4

4.5

3 1.25

Vehicles 9.2 %

Packaging 32.4 %

other 14.9 % insulation 27 % Profiles 34 %

Pipes 24 %

Construction 25.2 %

30°

2.5

0.1

Shore D

other 15 %

3 1.25

4.3

2.5

Acronym

Chemical name

Acronym

Chemical name

ABS

Acrylonitrile butadiene styrene

PE-HD

Polyethylene high density

ACM

Acrylic rubber

PE-LD

Polyethylene low density

ACS

Acrylonitrile chloroprene-styrene

PE-LLD

Polyethylene linear low density

ASA

Acrylonitrile styrene acrylate

PE-MD

Polyethylene medium density

a 0.1 mm ball tip is used. Each scale results in a value between 0 and 100, with

AU

Polyurethane rubber

PE-UHMW

Polyethylene ultra high molecular weight

higher values indicating a harder material. The specific Shore scale used is indi-

Br

Butadiene rubber

PE-ULD

Polyethylene ultra low density

cated in a suffix.

CA

Cellulose acetate

PE-VLD

Polyethylene very low density

CH

Hydrated cellulose, cellulose film (cellophane)

PEEK

Polyetheretherketone

Cr

Chloroprene rubber (neoprene)

PEK

Polyetherketone

CSF

Casein formaldehyde (casein plastic)

PET

Polyethylene terephthalate

EP

Epoxy resin

PET-G

Polyethylene terephthalate modified with glycol

EPDM

Ethylene propylene diene rubber

PF

Phenol formaldehyde resin

EPM

Ethylene propylene rubber

Pi

Polyimide

ETFE

Ethylene tetrafluoroethylene

PMA

Polymethylacrylate

EU

Polyether urethane rubber

PMMA

Polymethyl methacrylate

EVAC

Ethylene vinyl acetate

PMMi

Polymethyl methacrylimide

The material has a broad working temperature range from – 30 °C to + 140 °C. it is

iir

Butyl rubber

PoM

Polyoxymethylene (= polyacetal resin)

resistant against organic solutions such as alcohol as well as inorganic solutions

ir

isoprene rubber

PP

Polypropylene

such as salts, alkali leaches and acids. EPDM exhibits strong swelling properties in

LCP

Liquid crystal polymer

PPE

Polyphenylene ether

oils and fuels, which can have a detrimental effect on the longevity of some EPDM

MF

Melamine formaldehyde resin

PS

Polystyrene

products.

MPF

Melamine phenol formaldehyde resin

PTFE

Polytetrafluoroethylene

Trade names nordel (DuPont), Buna (Lanxess), Dutral (Polimeri), Keltan (DSM),

MUF

Melamine urea formaldehyde resin

PUr

Polyurethane

Vistalon (Exxon Mobil Chemical)

nBr

nitrile butadiene rubber

PVAC

Polyvinyl acetate

Manufacture Calendering for roofing membranes; extrusion for pipes, profiles and

nr

natural rubber

PVB

Polyvinyl butyral

tubing

PA

Polyamide

PVC

Polyvinyl chloride

Working, joining Gluing; EPDM-roofing membranes can be joined at their edges of

PAC

Polyacetylene

SAn

Styrene acrylonitrile

uncross-linked PE, using hot-air welding

PAEK

Polyacryletherketone

SB

Styrene Butadiene

PAn

Polyacrylonitrile

SP

Aromatic (saturated) polyester

Applications Bridge supports; waterproofing, for example membranes for flat

PB

Polybutylene

TPE

Thermoplastic elastomer

PBT

Polybutylene terephthalate

UF

Urea formaldehyde

PC

Polycarbonate

UP

Unsaturated polyester

PE

Polyethylene

35° Shore A

0.79

ETHYLENE PROPYLENE DIENE RUBBER (EPDM) of all the elastomers, EPDM 4.4

is most widely used in the field of construction. The basis polymer EPM (ethylene propylene rubber) has excellent aging stability, weather and chemical resistance.

Through the introduction of a diene, the polymer chains can be cross-linked with sulphur bridges to form ethylene propylene diene rubber (EPDM). EPDM is permanently elastic and has good mechanical properties even after extensive use. Due to its excellent UV and ozone stability, it is ideally suited for long-term use outdoors.

roofs; sealing strips in windows and façades; joint expansion strips for joints between concrete building elements

30

PLASTICS AND THEIR MANUFACTURE

ELASTOMERS

4.1 The use of plastics in Germany, 2007.

4.4 EPDM sealing profiles.

4.2 The applications of plastics in construction in Germany, 2007. 4.3 Acronyms for plastics according to Din En iSo 1043-1 (basic polymers) and Din iSo 1629 (rubbers and latices).

4.1

4.5 Test specimen for determining the hardness of plastics according to the

Shore classification.

4.2 Electronics 7.4 % Furniture 3.8 % Household products 2.9 % Agriculture 2.5 % Medicine 1.7 %

31

4.4

4.5

3 1.25

Vehicles 9.2 %

Packaging 32.4 %

other 14.9 % insulation 27 % Profiles 34 %

Pipes 24 %

Construction 25.2 %

30°

2.5

0.1

Shore D

other 15 %

3 1.25

4.3

2.5

Acronym

Chemical name

Acronym

Chemical name

ABS

Acrylonitrile butadiene styrene

PE-HD

Polyethylene high density

ACM

Acrylic rubber

PE-LD

Polyethylene low density

ACS

Acrylonitrile chloroprene-styrene

PE-LLD

Polyethylene linear low density

ASA

Acrylonitrile styrene acrylate

PE-MD

Polyethylene medium density

a 0.1 mm ball tip is used. Each scale results in a value between 0 and 100, with

AU

Polyurethane rubber

PE-UHMW

Polyethylene ultra high molecular weight

higher values indicating a harder material. The specific Shore scale used is indi-

Br

Butadiene rubber

PE-ULD

Polyethylene ultra low density

cated in a suffix.

CA

Cellulose acetate

PE-VLD

Polyethylene very low density

CH

Hydrated cellulose, cellulose film (cellophane)

PEEK

Polyetheretherketone

Cr

Chloroprene rubber (neoprene)

PEK

Polyetherketone

CSF

Casein formaldehyde (casein plastic)

PET

Polyethylene terephthalate

EP

Epoxy resin

PET-G

Polyethylene terephthalate modified with glycol

EPDM

Ethylene propylene diene rubber

PF

Phenol formaldehyde resin

EPM

Ethylene propylene rubber

Pi

Polyimide

ETFE

Ethylene tetrafluoroethylene

PMA

Polymethylacrylate

EU

Polyether urethane rubber

PMMA

Polymethyl methacrylate

EVAC

Ethylene vinyl acetate

PMMi

Polymethyl methacrylimide

The material has a broad working temperature range from – 30 °C to + 140 °C. it is

iir

Butyl rubber

PoM

Polyoxymethylene (= polyacetal resin)

resistant against organic solutions such as alcohol as well as inorganic solutions

ir

isoprene rubber

PP

Polypropylene

such as salts, alkali leaches and acids. EPDM exhibits strong swelling properties in

LCP

Liquid crystal polymer

PPE

Polyphenylene ether

oils and fuels, which can have a detrimental effect on the longevity of some EPDM

MF

Melamine formaldehyde resin

PS

Polystyrene

products.

MPF

Melamine phenol formaldehyde resin

PTFE

Polytetrafluoroethylene

Trade names nordel (DuPont), Buna (Lanxess), Dutral (Polimeri), Keltan (DSM),

MUF

Melamine urea formaldehyde resin

PUr

Polyurethane

Vistalon (Exxon Mobil Chemical)

nBr

nitrile butadiene rubber

PVAC

Polyvinyl acetate

Manufacture Calendering for roofing membranes; extrusion for pipes, profiles and

nr

natural rubber

PVB

Polyvinyl butyral

tubing

PA

Polyamide

PVC

Polyvinyl chloride

Working, joining Gluing; EPDM-roofing membranes can be joined at their edges of

PAC

Polyacetylene

SAn

Styrene acrylonitrile

uncross-linked PE, using hot-air welding

PAEK

Polyacryletherketone

SB

Styrene Butadiene

PAn

Polyacrylonitrile

SP

Aromatic (saturated) polyester

Applications Bridge supports; waterproofing, for example membranes for flat

PB

Polybutylene

TPE

Thermoplastic elastomer

PBT

Polybutylene terephthalate

UF

Urea formaldehyde

PC

Polycarbonate

UP

Unsaturated polyester

PE

Polyethylene

35° Shore A

0.79

ETHYLENE PROPYLENE DIENE RUBBER (EPDM) of all the elastomers, EPDM 4.4

is most widely used in the field of construction. The basis polymer EPM (ethylene propylene rubber) has excellent aging stability, weather and chemical resistance.

Through the introduction of a diene, the polymer chains can be cross-linked with sulphur bridges to form ethylene propylene diene rubber (EPDM). EPDM is permanently elastic and has good mechanical properties even after extensive use. Due to its excellent UV and ozone stability, it is ideally suited for long-term use outdoors.

roofs; sealing strips in windows and façades; joint expansion strips for joints between concrete building elements

42

PLASTICS AND THEIR MANUFACTURE

THERMOPLASTICS

4.25 Thermoplastic foam casting: through the addition of a foaming agent, a low-density integral skin foam is created. 4.26 Casting: in this pressureless process, the molten material is poured into an open mould and polymerised through the input of energy. 4.27 Foaming: a foaming agent is added to the mass that causes air bubbles to form.

4.28 Integral skin foam has a porous core and a smooth, cell-free surface.

4.25

Foaming

4.26 4.27 Moulding compound

Prefoaming

Interim storage

Foam block

4.28

Polymer

Liquid moulding compound

Openable mould with smooth surface

Heated mould Mould

Foaming agent

Pressure application

This process is commonly used for the manufacture of PMMA GS, which as a

are primarily additive fabrication processes in which the three-dimensional body

semi-finished material is less prone to stress cracking than extruded materials

is created through the layer by layer application of a material. An exception is

and is therefore more suitable for reshaping and post-processing. Panel thick-

CNC milling (CNC = Computerised Numerical Control) in which a finished item is

nesses of between 2–250 mm can be poured, but the polymerisation process of

cut or milled from a massive block of material based on data from a digital model.

thick p ­ anels and large items can sometimes take several weeks.

Because the mould used in conventional processes is replaced by a digital model, the production process is more flexible in terms of form, quantity and lead time.

4.27

Foaming Foams are materials with a low bulk density and a continuous cellu-

DDM techniques make it possible to realise prototypes and small quantities which

lar structure. Foams may be classified according to their structure as open-cell,

could previously only be produced using moulds specially developed for the respec-

closed-cell and mixed-cell foams. Bubbles of air form in the mass caused by foam-

tive item. The cost-effectiveness of the process depends on the quantity produced

ing agents added to the mixture which vaporise under heat or by gases that result

and should be weighed up against the costs of conventional production processes

from the polymerisation process. The process is divided into stages: prefoaming,

such as injection moulding. With DDM techniques, forms can be designed that do

interim storage and final foaming. In the final stage the prefoamed material is

not need to take de-moulding (mould removal) into account. The ability to directly

passed into a mould and shaped into its end form. Common methods include injec-

test and assess the physical prototype allows one to avoid construction errors in

tion moulding or in-mould skinning for items made of integral skin foam or extru-

the final production. The dimensions of the items that can be produced are still

sion for semi-finished products. Although theoretically all thermoplastics can be

quite limited, but in some cases elements measuring several metres have been

used for foaming, polystyrene and polyurethane are most commonly used.

produced. Depending on the production method used, the strength of the result-

Foams differ from the compact form of the source material primarily in terms of density and a correspondingly much reduced thermal transmittance. For this ­reason they are ideally suited for use as an insulation material. The stiffness of rigid foams can be even higher than the original material in its compact form. The combustibility of the original material remains unchanged.

ing items is generally lower than those produced using conventional thermoplastic processes.

Rapid prototyping techniques make it possible to realise physical three-dimensional prototypes with complex geometries and cavities. The various techniques are divided into laser-based and non-laser-based approaches. Depending on the

Thermoplastic foam casting is a variant of injection moulding in which the addi-

method used, different plastics can be used in liquid or solid form, for example

4.25

tion of a foaming agent such as CO2 or nitrogen causes the production of so-called

ABS, polyamide, polycarbonate or photopolymers as well as elastic plastics, paper,

4.28

integral skin foam with a lower density. The expansion of the foam is limited by the

wax, ceramics or metal. The combination of different materials is also possible.

dimensions of the mould, which in turn is responsible for the smooth surface of

Some of the most widespread processes are:

the end product. The structure of the end product has a porous foam core and a

Stereolithography (STL) Layer for layer solidification of a liquid photopolymer

smooth cell-free surface.

using a laser beam. Suitable materials are thermosetting resins.

Solid Ground Curing (SGC) Layer for layer solidification of a photopolymer using UV

Direct Digital Manufacturing The terms Direct Digital Manufacturing (DDM)

light. Suitable materials are thermosetting resins.

or generative fabrication are used generically for processes such as Rapid Proto-

Selective Laser Sintering, Laser Sintering (SLS, LS) Layer for layer localised sinter-

typing (RP), Rapid Tooling (RT) and Rapid Manufacturing (RM), all of which make it

ing of a source material in powder form. Suitable materials are thermoplastic plas-

possible to generate physical items from digital computer data. DDM techniques

tics, wax and metal.

43

42

PLASTICS AND THEIR MANUFACTURE

THERMOPLASTICS

4.25 Thermoplastic foam casting: through the addition of a foaming agent, a low-density integral skin foam is created. 4.26 Casting: in this pressureless process, the molten material is poured into an open mould and polymerised through the input of energy. 4.27 Foaming: a foaming agent is added to the mass that causes air bubbles to form.

4.28 Integral skin foam has a porous core and a smooth, cell-free surface.

4.25

Foaming

4.26 4.27 Moulding compound

Prefoaming

Interim storage

Foam block

4.28

Polymer

Liquid moulding compound

Openable mould with smooth surface

Heated mould Mould

Foaming agent

Pressure application

This process is commonly used for the manufacture of PMMA GS, which as a

are primarily additive fabrication processes in which the three-dimensional body

semi-finished material is less prone to stress cracking than extruded materials

is created through the layer by layer application of a material. An exception is

and is therefore more suitable for reshaping and post-processing. Panel thick-

CNC milling (CNC = Computerised Numerical Control) in which a finished item is

nesses of between 2–250 mm can be poured, but the polymerisation process of

cut or milled from a massive block of material based on data from a digital model.

thick p ­ anels and large items can sometimes take several weeks.

Because the mould used in conventional processes is replaced by a digital model, the production process is more flexible in terms of form, quantity and lead time.

4.27

Foaming Foams are materials with a low bulk density and a continuous cellu-

DDM techniques make it possible to realise prototypes and small quantities which

lar structure. Foams may be classified according to their structure as open-cell,

could previously only be produced using moulds specially developed for the respec-

closed-cell and mixed-cell foams. Bubbles of air form in the mass caused by foam-

tive item. The cost-effectiveness of the process depends on the quantity produced

ing agents added to the mixture which vaporise under heat or by gases that result

and should be weighed up against the costs of conventional production processes

from the polymerisation process. The process is divided into stages: prefoaming,

such as injection moulding. With DDM techniques, forms can be designed that do

interim storage and final foaming. In the final stage the prefoamed material is

not need to take de-moulding (mould removal) into account. The ability to directly

passed into a mould and shaped into its end form. Common methods include injec-

test and assess the physical prototype allows one to avoid construction errors in

tion moulding or in-mould skinning for items made of integral skin foam or extru-

the final production. The dimensions of the items that can be produced are still

sion for semi-finished products. Although theoretically all thermoplastics can be

quite limited, but in some cases elements measuring several metres have been

used for foaming, polystyrene and polyurethane are most commonly used.

produced. Depending on the production method used, the strength of the result-

Foams differ from the compact form of the source material primarily in terms of density and a correspondingly much reduced thermal transmittance. For this ­reason they are ideally suited for use as an insulation material. The stiffness of rigid foams can be even higher than the original material in its compact form. The combustibility of the original material remains unchanged.

ing items is generally lower than those produced using conventional thermoplastic processes.

Rapid prototyping techniques make it possible to realise physical three-dimensional prototypes with complex geometries and cavities. The various techniques are divided into laser-based and non-laser-based approaches. Depending on the

Thermoplastic foam casting is a variant of injection moulding in which the addi-

method used, different plastics can be used in liquid or solid form, for example

4.25

tion of a foaming agent such as CO2 or nitrogen causes the production of so-called

ABS, polyamide, polycarbonate or photopolymers as well as elastic plastics, paper,

4.28

integral skin foam with a lower density. The expansion of the foam is limited by the

wax, ceramics or metal. The combination of different materials is also possible.

dimensions of the mould, which in turn is responsible for the smooth surface of

Some of the most widespread processes are:

the end product. The structure of the end product has a porous foam core and a

Stereolithography (STL) Layer for layer solidification of a liquid photopolymer

smooth cell-free surface.

using a laser beam. Suitable materials are thermosetting resins.

Solid Ground Curing (SGC) Layer for layer solidification of a photopolymer using UV

Direct Digital Manufacturing The terms Direct Digital Manufacturing (DDM)

light. Suitable materials are thermosetting resins.

or generative fabrication are used generically for processes such as Rapid Proto-

Selective Laser Sintering, Laser Sintering (SLS, LS) Layer for layer localised sinter-

typing (RP), Rapid Tooling (RT) and Rapid Manufacturing (RM), all of which make it

ing of a source material in powder form. Suitable materials are thermoplastic plas-

possible to generate physical items from digital computer data. DDM techniques

tics, wax and metal.

43

52

53

PLASTICS AND THEIR MANUFACTURE

THERMOSETS

it possible to manufacture building elements that are highly transparent. Woven

4.41 Different forms of glass fibre products.

staple-fibre glass textile represents an especially soft and absorbent variant, another type is the spacer fabric. The latter consists of two textile finishing layers 4.43

4.41

of E-glass with a silane coating, which are bound together and held apart by vertical spacer fibres. Once impregnated with polyester resin or epoxy resin, the textile automatically assumes its design thickness. This makes it very easy to fabricate sandwiched laminates. Spacer fabrics are most commonly used for manual laminating methods. The waviness of a textile generally has a negative effect on its orthotropic stiffness. in particular in the direction of the warp a certain degree of structural extension is unavoidable. roving

Thread

Core yarn

MANUAL TECHNIQUES Hand lay-up lamination is a comparatively straightfor-

ward process and is suitable for the fabrication of small quantities of freeform 4.44

prototypes and sheet-like building elements. Various materials can be used for the formwork. Simple forms can be made of sheet metal or timber formwork. rigid polyurethane foam with a density of 400 kg/m3 is easier to use for making freeform or biaxially curved concave forms. Forms that are applied from outside the building element and describe its outer surface are known as negative or female moulds. Forms that describe the inner surface of the element are known as positive or male moulds. An important criteria for the choice of material for the mould is resistance against the solvent used in the resin. A suitably durable material should be chosen for moulds or forms that are to be used repeatedly. Large moulds are made of several individual parts that are assembled and glued together. The sur-

Textile glass mat

Knitted fabric

Unidirectional non-woven

Biaxial non-woven

Fabric: plain weave

Fabric: braided weave

face of the mould defines the surface quality of the resulting formed element. The surface not facing the mould is always rough and may need additional finishing if it needs to be of a certain quality.

A constraint for the development of moulds is the fact that not all geometric forms can be removed from the form. For this reason, forms that are undercut or significantly twisted should be avoided. The process of lamination begins with a thin (0.3–0.6 mm) non-reinforced “gelcoat�. This stops the structure of the fibres from showing through and serves as a weather protection layer. it can also be used to lend it a certain colour. The matrix material and fibre matting are then applied wet on wet in alternate layers. A certain degree of skill is required to create evenly dense layers of material with as few trapped air bubbles as possible.

Hand lay-up lamination is a rather laborious but low-cost method. The manufacture of high-performance building elements using manual lamination is difficult as it is hard to precisely control the material properties. The fibre proportion is generally less than 45 % by volume. The quality of the laminate can be improved by applying different pressure techniques. With a vacuum forming technique, the still wet laminate is covered with a porous adhesion-preventing film and an absorbent textile. After covering with a vacuum bag and sealing the edges, a vacuum is created. All excess resin and trapped air bubbles are sucked out and the laminate then hardens under normal atmospheric pressure. This results in very dense laminates with a high fibre content. Using this technique it is also possible to impregnate dry lay-up laminates with resin afterwards. This so-called resin infusion

Wrapped yarn

52

53

PLASTICS AND THEIR MANUFACTURE

THERMOSETS

it possible to manufacture building elements that are highly transparent. Woven

4.41 Different forms of glass fibre products.

staple-fibre glass textile represents an especially soft and absorbent variant, another type is the spacer fabric. The latter consists of two textile finishing layers 4.43

4.41

of E-glass with a silane coating, which are bound together and held apart by vertical spacer fibres. Once impregnated with polyester resin or epoxy resin, the textile automatically assumes its design thickness. This makes it very easy to fabricate sandwiched laminates. Spacer fabrics are most commonly used for manual laminating methods. The waviness of a textile generally has a negative effect on its orthotropic stiffness. in particular in the direction of the warp a certain degree of structural extension is unavoidable. roving

Thread

Core yarn

MANUAL TECHNIQUES Hand lay-up lamination is a comparatively straightfor-

ward process and is suitable for the fabrication of small quantities of freeform 4.44

prototypes and sheet-like building elements. Various materials can be used for the formwork. Simple forms can be made of sheet metal or timber formwork. rigid polyurethane foam with a density of 400 kg/m3 is easier to use for making freeform or biaxially curved concave forms. Forms that are applied from outside the building element and describe its outer surface are known as negative or female moulds. Forms that describe the inner surface of the element are known as positive or male moulds. An important criteria for the choice of material for the mould is resistance against the solvent used in the resin. A suitably durable material should be chosen for moulds or forms that are to be used repeatedly. Large moulds are made of several individual parts that are assembled and glued together. The sur-

Textile glass mat

Knitted fabric

Unidirectional non-woven

Biaxial non-woven

Fabric: plain weave

Fabric: braided weave

face of the mould defines the surface quality of the resulting formed element. The surface not facing the mould is always rough and may need additional finishing if it needs to be of a certain quality.

A constraint for the development of moulds is the fact that not all geometric forms can be removed from the form. For this reason, forms that are undercut or significantly twisted should be avoided. The process of lamination begins with a thin (0.3–0.6 mm) non-reinforced “gelcoat�. This stops the structure of the fibres from showing through and serves as a weather protection layer. it can also be used to lend it a certain colour. The matrix material and fibre matting are then applied wet on wet in alternate layers. A certain degree of skill is required to create evenly dense layers of material with as few trapped air bubbles as possible.

Hand lay-up lamination is a rather laborious but low-cost method. The manufacture of high-performance building elements using manual lamination is difficult as it is hard to precisely control the material properties. The fibre proportion is generally less than 45 % by volume. The quality of the laminate can be improved by applying different pressure techniques. With a vacuum forming technique, the still wet laminate is covered with a porous adhesion-preventing film and an absorbent textile. After covering with a vacuum bag and sealing the edges, a vacuum is created. All excess resin and trapped air bubbles are sucked out and the laminate then hardens under normal atmospheric pressure. This results in very dense laminates with a high fibre content. Using this technique it is also possible to impregnate dry lay-up laminates with resin afterwards. This so-called resin infusion

Wrapped yarn

64

Material Polycarbonate (PC) Product Makrolon solid PC sheets Manufacturer Bayer Sheet Europe GmbH www.bayersheeteurope.com

FINISHED AND SEMI-FINISHED PRODUCTS

SOLID SHEETS

Makrolon solid polycarbonate sheets are suitable for indoor or outdoor use where

5.8 PETG synthetic resin: edge sections of Varia product samples showing a range of layer ­ ompositions. 5.9 Varia product samples with different colours, surface finishes and designs, c and intermediary layers.

thermal stability and shock resistance are of paramount importance and where sheets need to be thermoformable. Compared with PMMA, polycarbonate sheets are not quite as transparent. Makrolon solid sheets are available with UV-pro-

5.8

tective, scratch-resistant and chemically resistant surfaces as well as functional coatings. Makrolon Hygard is a multi-layer laminated transparent sheet that offers protection against forced entry and ballistic impact. With additional fire safety modifications, certain products in the range are classified as building material class B1 (DIN 4102). Available in thicknesses between 0.75–15 mm, the standard sheet dimensions are 2050 × 1250 mm as well as 3050 × 2050 mm. Larger and custom dimensions can be produced on demand.

Properties and design possibilities (product-dependent): —— Possible variants: transparent colourless, transparent coloured and white translucent —— 88 % light transmission for a thickness of 3 mm (Makrolon GP clear 099) —— A range of surface finishes from polished to textured —— Impact-resistant, shatterproof and bulletproof (depending on material thickness and layer structure) —— Reformable at cold and hot temperatures —— Service temperature range: – 100 °C to + 120 °C —— Building material class B2 (DIN 4102); Makrolon GP is also available as B1 for ­indoor use

Material Ecoresin (PETG synthetic resin) Product Varia Manufacturer 3form www.3form.eu

The Varia series of products are manufactured as solid sheets from transparent

5.8

Ecoresin. Ecoresin is a thermoplastic resin with a 40 % recycled material content that serves as a matrix for embedding different kinds of materials within the panel.

The system of different intermediary layers, along with colours and surface textures, offer numerous different design possibilities. Varia products can also be made according to client’s individual wishes.

Properties and design possibilities: —— A variety of possible different intermediate layers and colouring —— Surface finishes of the front and rear can be different —— High chemical stability —— UV-stabilised —— Suitable for use in wet rooms (showers, bathrooms) when edges are sealed —— Bonding using two-component adhesive (as with Plexiglas) —— Can be thermoformed at a temperature of about 110–120 °C —— Can be cold-formed up to a certain minimum radius —— Can be machined (working properties much like MDF) —— Panel thicknesses 1.5, 3, 5, 6, 10, 12, 19 and 25 mm —— Dimensions 1219 × 2438 mm, 1219 × 3048 mm, special dimensions 1524 × 3048 mm —— Fire safety classification: Euro class B, s1, d0

5.9

65

5.9

64

Material Polycarbonate (PC) Product Makrolon solid PC sheets Manufacturer Bayer Sheet Europe GmbH www.bayersheeteurope.com

FINISHED AND SEMI-FINISHED PRODUCTS

SOLID SHEETS

Makrolon solid polycarbonate sheets are suitable for indoor or outdoor use where

5.8 PETG synthetic resin: edge sections of Varia product samples showing a range of layer ­ ompositions. 5.9 Varia product samples with different colours, surface finishes and designs, c and intermediary layers.

thermal stability and shock resistance are of paramount importance and where sheets need to be thermoformable. Compared with PMMA, polycarbonate sheets are not quite as transparent. Makrolon solid sheets are available with UV-pro-

5.8

tective, scratch-resistant and chemically resistant surfaces as well as functional coatings. Makrolon Hygard is a multi-layer laminated transparent sheet that offers protection against forced entry and ballistic impact. With additional fire safety modifications, certain products in the range are classified as building material class B1 (DIN 4102). Available in thicknesses between 0.75–15 mm, the standard sheet dimensions are 2050 × 1250 mm as well as 3050 × 2050 mm. Larger and custom dimensions can be produced on demand.

Properties and design possibilities (product-dependent): —— Possible variants: transparent colourless, transparent coloured and white translucent —— 88 % light transmission for a thickness of 3 mm (Makrolon GP clear 099) —— A range of surface finishes from polished to textured —— Impact-resistant, shatterproof and bulletproof (depending on material thickness and layer structure) —— Reformable at cold and hot temperatures —— Service temperature range: – 100 °C to + 120 °C —— Building material class B2 (DIN 4102); Makrolon GP is also available as B1 for ­indoor use

Material Ecoresin (PETG synthetic resin) Product Varia Manufacturer 3form www.3form.eu

The Varia series of products are manufactured as solid sheets from transparent

5.8

Ecoresin. Ecoresin is a thermoplastic resin with a 40 % recycled material content that serves as a matrix for embedding different kinds of materials within the panel.

The system of different intermediary layers, along with colours and surface textures, offer numerous different design possibilities. Varia products can also be made according to client’s individual wishes.

Properties and design possibilities: —— A variety of possible different intermediate layers and colouring —— Surface finishes of the front and rear can be different —— High chemical stability —— UV-stabilised —— Suitable for use in wet rooms (showers, bathrooms) when edges are sealed —— Bonding using two-component adhesive (as with Plexiglas) —— Can be thermoformed at a temperature of about 110–120 °C —— Can be cold-formed up to a certain minimum radius —— Can be machined (working properties much like MDF) —— Panel thicknesses 1.5, 3, 5, 6, 10, 12, 19 and 25 mm —— Dimensions 1219 × 2438 mm, 1219 × 3048 mm, special dimensions 1524 × 3048 mm —— Fire safety classification: Euro class B, s1, d0

5.9

65

5.9

74

FINISHED AND SEMI-FINISHED PRODUCTS

SANDWICH PANELS

5.21 VarioLine is a lightweight building board with integral foam structure made of polypropylene, polyethylene or polystyrene. 5.22 3D-Tex product variants: 3D-Tex Standard (white textile), 3D-Tex 500 R1 (yellowish polyester nonwoven fabric with melamine resin coating), 3D-Tex PP/KHF (mixed-fibre non­ woven with 50 % polypropylene and 50 % natural fibres). 5.23 Parabeam: a 5 mm thick flat translucent panel made of GRP.

5.24 Frontal view of a GRP Scobatherm panel. 5.25 Section through an aerogel granulate-filled

75

­Scobatherm panel.

5.24

5.25

5.22

5.21

5.23

The translucent Scobatherm insulation element represents a variant of the light

5.24

element that is filled with aerogel. Panels with a thickness of 50 mm can attain a

5.25

U-value of 0.41 W/m2 K Material GRP, PUR, PS, PVC Product Sandwich panel with foam core Manufacturer Various

Sandwich panels with a rigid PUR foam core and GRP facing layers are ideally suitable for lightweight construction due to their high stability and low weight.

Depending on their respective thickness, they can also have an insulating function. The sandwich elements can be manufactured to serve specific purposes, for example, the facing layers can be made of different thermosetting matrix resins or alternatively of thin metal sheeting.

Material Glass fibre-­ reinforced plastic (GRP) Product Scobaelement – ILE translucent sandwich panels Manufacturer Scobalit www.scobalit.ch

The translucent light element Scobaelement is made of glass fibre-reinforced

5.13

Properties and design possibilities:

poly­ester resin and is available in two different cross-sectional forms as a sand-

—— Core layer made of PS-, PU- or PVC foam with different degrees of firmness

wich element with covering layers and connecting webs. The durability of the ele-

—— Facing layer of GRP or metal

ments in outdoor and indoor use is similar to the Scobalight products. The sand-

—— Integration of inserts is possible for fixings or mountings

wich construction lends them a greater stiffness and is economical in its use of

—— Good dimensional accuracy

materials. With a span length of 2500 × 2000 mm, the elements can sustain a per-

—— Suitable for use outdoors

missible surface load of up to 180 kg/m depending on the element thickness.

—— Maximum dimensions 3200 × 15000 mm

2

­Special inserts need to be inserted during production for drilled holes.

Properties and design possibilities: —— Standard colour: natural but can also be manufactured in other colours —— Anti-graffiti coating —— Maximum dimensions 8000 × 2400 mm —— Thicknesses 20, 30 and 50 mm (Type M = waveform webs), 25 and 40 mm (Type P = vertical webs) —— Building material class B1 (DIN 4102) also available

5.26

74

FINISHED AND SEMI-FINISHED PRODUCTS

SANDWICH PANELS

5.21 VarioLine is a lightweight building board with integral foam structure made of polypropylene, polyethylene or polystyrene. 5.22 3D-Tex product variants: 3D-Tex Standard (white textile), 3D-Tex 500 R1 (yellowish polyester nonwoven fabric with melamine resin coating), 3D-Tex PP/KHF (mixed-fibre non­ woven with 50 % polypropylene and 50 % natural fibres). 5.23 Parabeam: a 5 mm thick flat translucent panel made of GRP.

5.24 Frontal view of a GRP Scobatherm panel. 5.25 Section through an aerogel granulate-filled

75

­Scobatherm panel.

5.24

5.25

5.22

5.21

5.23

The translucent Scobatherm insulation element represents a variant of the light

5.24

element that is filled with aerogel. Panels with a thickness of 50 mm can attain a

5.25

U-value of 0.41 W/m2 K Material GRP, PUR, PS, PVC Product Sandwich panel with foam core Manufacturer Various

Sandwich panels with a rigid PUR foam core and GRP facing layers are ideally suitable for lightweight construction due to their high stability and low weight.

Depending on their respective thickness, they can also have an insulating function. The sandwich elements can be manufactured to serve specific purposes, for example, the facing layers can be made of different thermosetting matrix resins or alternatively of thin metal sheeting.

Material Glass fibre-­ reinforced plastic (GRP) Product Scobaelement – ILE translucent sandwich panels Manufacturer Scobalit www.scobalit.ch

The translucent light element Scobaelement is made of glass fibre-reinforced

5.13

Properties and design possibilities:

poly­ester resin and is available in two different cross-sectional forms as a sand-

—— Core layer made of PS-, PU- or PVC foam with different degrees of firmness

wich element with covering layers and connecting webs. The durability of the ele-

—— Facing layer of GRP or metal

ments in outdoor and indoor use is similar to the Scobalight products. The sand-

—— Integration of inserts is possible for fixings or mountings

wich construction lends them a greater stiffness and is economical in its use of

—— Good dimensional accuracy

materials. With a span length of 2500 × 2000 mm, the elements can sustain a per-

—— Suitable for use outdoors

missible surface load of up to 180 kg/m depending on the element thickness.

—— Maximum dimensions 3200 × 15000 mm

2

­Special inserts need to be inserted during production for drilled holes.

Properties and design possibilities: —— Standard colour: natural but can also be manufactured in other colours —— Anti-graffiti coating —— Maximum dimensions 8000 × 2400 mm —— Thicknesses 20, 30 and 50 mm (Type M = waveform webs), 25 and 40 mm (Type P = vertical webs) —— Building material class B1 (DIN 4102) also available

5.26

96

Chanel Mobile Art Pavilion

1 Chanel Mobile Art Pavilion in Central Park, New York. 2 Detail of the façade. 3 Erecting the façade.

4 Organisation of building functions.

1

Location Hong Kong, China; Tokyo, Japan; New York, USA Material GRP (façade), ETFE (skylights) Completion 2008

97

PLASTICS AS BUILDING ENVELOPE

CASE STUDIES

2

Architecture Zaha Hadid Architects Structural engineering ARUP GRP elements manufacturer Stage One Creative Services Ltd

The mobile pavilion for the fashion company Chanel serves as an exhibition space for artworks inspired by Chanel that have been specially created for the pavilion.

It was conceived as a temporary building for use in different metropolitan cities throughout the world.

3

The spatial concept is based on the shape of a torus whose plan has been distorted into a triangular shape. The entrance to the pavilion is via a terrace that lies between the exhibition space and a ticket office. The exhibition area of the 700 m2 pavilion is arranged around a 65 m2 central courtyard that serves as a rest area and can be used for special events. Skylights made of ETFE cushions in the outer ring and over the inner courtyard provide natural illumination during the day.

The main construction of the 6 m high pavilion consists of a steel skeleton framework. The curved steel ribs made of I-sections, whose radial arrangement follows almost exactly the complex geometry of the building, serve simultaneously as the supporting construction for the sections of the plastic façade. The GRP elements have a lip around their edges and are bolted to the supporting construction through factory-glued and screwed steel anchor plates at the seams. The seams between the plastic panels rhythmically delineate the surface of the building’s shell.

The building geometry was developed with the help of digital design and modelling tools. This made it possible to effect a continuous digital process from the design to the production of the individual elements. Because of the changing curvature of the building volume, an individual mould had to be built for each of the 400 GRP elements. The GRP elements were then manufactured in a hand lay-up process and lacquered. The 12 mm thick elements are a sandwich construction with different core layers and two polyester resin facing layers. The required fire ­behaviour properties of the GRP elements were ascertained using test procedures.

The s ­ urface of the interior is formed by an elastic textile membrane.

4

A

The dimensions of each of the individual building segments are no wider than 2.25 m for transport reasons. The project is a spectacular demonstration of the uncompromising conversion of a complex design into built reality and showcases impressively the shaping possibilities of plastics.

Exhibition area

Interior courtyard

B

Cloakroom Terrace

Tickets

Entrance

A 01

5

10 m

B

96

Chanel Mobile Art Pavilion

1 Chanel Mobile Art Pavilion in Central Park, New York. 2 Detail of the façade. 3 Erecting the façade.

4 Organisation of building functions.

1

Location Hong Kong, China; Tokyo, Japan; New York, USA Material GRP (façade), ETFE (skylights) Completion 2008

97

PLASTICS AS BUILDING ENVELOPE

CASE STUDIES

2

Architecture Zaha Hadid Architects Structural engineering ARUP GRP elements manufacturer Stage One Creative Services Ltd

The mobile pavilion for the fashion company Chanel serves as an exhibition space for artworks inspired by Chanel that have been specially created for the pavilion.

It was conceived as a temporary building for use in different metropolitan cities throughout the world.

3

The spatial concept is based on the shape of a torus whose plan has been distorted into a triangular shape. The entrance to the pavilion is via a terrace that lies between the exhibition space and a ticket office. The exhibition area of the 700 m2 pavilion is arranged around a 65 m2 central courtyard that serves as a rest area and can be used for special events. Skylights made of ETFE cushions in the outer ring and over the inner courtyard provide natural illumination during the day.

The main construction of the 6 m high pavilion consists of a steel skeleton framework. The curved steel ribs made of I-sections, whose radial arrangement follows almost exactly the complex geometry of the building, serve simultaneously as the supporting construction for the sections of the plastic façade. The GRP elements have a lip around their edges and are bolted to the supporting construction through factory-glued and screwed steel anchor plates at the seams. The seams between the plastic panels rhythmically delineate the surface of the building’s shell.

The building geometry was developed with the help of digital design and modelling tools. This made it possible to effect a continuous digital process from the design to the production of the individual elements. Because of the changing curvature of the building volume, an individual mould had to be built for each of the 400 GRP elements. The GRP elements were then manufactured in a hand lay-up process and lacquered. The 12 mm thick elements are a sandwich construction with different core layers and two polyester resin facing layers. The required fire ­behaviour properties of the GRP elements were ascertained using test procedures.

The s ­ urface of the interior is formed by an elastic textile membrane.

4

A

The dimensions of each of the individual building segments are no wider than 2.25 m for transport reasons. The project is a spectacular demonstration of the uncompromising conversion of a complex design into built reality and showcases impressively the shaping possibilities of plastics.

Exhibition area

Interior courtyard

B

Cloakroom Terrace

Tickets

Entrance

A 01

5

10 m

B

112

PLASTICS AS BUILDING ENVELOPE

CASE STUDIES

Farben des Konsums

1 “Farben des Konsums” light installation in an unused part of Potsdamer Platz underground station

in Berlin. 2 The surface areas of each colour of the backlit plastic elements is proportional to its use in plastic packaging.

1

Location Berlin, Germany Material Recycled thermoplastic material Completion 2003 (temporary)

Design Bär + Knell: Beata Bär, Gerhard Bär, Hartmut Knell

“Die Farben des Konsums” (The Colours of Consumption) is a light installation project made of recycled plastic packaging materials that has been staged at ­several different locations. Originally created as part of an exhibition entitled “Kunst, Kunststoff, Kunststoffrecycling” (Art, Plastics, Recycling) by the German Asso­ciation for Plastics Recycling (DKR), the wall of coloured light was installed along a 144 m stretch of a tunnel and future underground station of the U3 line beneath the Potsdamer Platz in Berlin.

The exhibition also featured the work of various artists and companies that produce high-quality designs, for example furniture, out of recycled plastic material.

The intention is that visitors grasp a better understanding of the raw materials cycle through the aesthetic quality of the objects and that this will heighten consumer awareness of plastic packaging and recycling.

The name of the project refers to the proportional distribution of colours in the packaging material of everyday consumer goods. For example, the white colour is derived from the plastic bottles used for mineral water. Once the plastic pack­ aging had been sorted by colour, they were then ground down to granulate. The plastic elements were created through hot-pressing. Initially, individual items of furniture and small runs were produced in this way. The plastic panels used in the installation “Die Farben des Konsums” were handmade by the artists and illuminated from behind.

2

113

112

PLASTICS AS BUILDING ENVELOPE

CASE STUDIES

Farben des Konsums

1 “Farben des Konsums” light installation in an unused part of Potsdamer Platz underground station

in Berlin. 2 The surface areas of each colour of the backlit plastic elements is proportional to its use in plastic packaging.

1

Location Berlin, Germany Material Recycled thermoplastic material Completion 2003 (temporary)

Design Bär + Knell: Beata Bär, Gerhard Bär, Hartmut Knell

“Die Farben des Konsums” (The Colours of Consumption) is a light installation project made of recycled plastic packaging materials that has been staged at ­several different locations. Originally created as part of an exhibition entitled “Kunst, Kunststoff, Kunststoffrecycling” (Art, Plastics, Recycling) by the German Asso­ciation for Plastics Recycling (DKR), the wall of coloured light was installed along a 144 m stretch of a tunnel and future underground station of the U3 line beneath the Potsdamer Platz in Berlin.

The exhibition also featured the work of various artists and companies that produce high-quality designs, for example furniture, out of recycled plastic material.

The intention is that visitors grasp a better understanding of the raw materials cycle through the aesthetic quality of the objects and that this will heighten consumer awareness of plastic packaging and recycling.

The name of the project refers to the proportional distribution of colours in the packaging material of everyday consumer goods. For example, the white colour is derived from the plastic bottles used for mineral water. Once the plastic pack­ aging had been sorted by colour, they were then ground down to granulate. The plastic elements were created through hot-pressing. Initially, individual items of furniture and small runs were produced in this way. The plastic panels used in the installation “Die Farben des Konsums” were handmade by the artists and illuminated from behind.

2

113

130

D-Tower

1 Daytime view. 2 Detail: the consistent 45° angle of the glass fibre-reinforcement and the ­returned edges of the GRP moulded items in the flange areas are clearly visible. 3 At night the tower is ­illuminated with LEDs. 4 The D-Tower is made up of 19 individual elements.

1

Location Doetinchem, Netherlands Material Glass fibre-reinforced epoxy resin Completion 2004

131

PLASTICS AS BUILDING STRUCTURE

CASE STUDIES

2

Architecture NOX Architects, Lars Spuybroek Structural engineering Bollinger + Grohmann Ingenieure

The 12 m high tower sculpture is part of an interactive art project. Created together with the artist Q. S. Serafijn, the concept involved the local residents, who were asked to answer regular questionnaires. Their responses were then analysed by computer to determine the general emotional state of the community. The currently predominant emotion is represented by a colour that is then used to illuminate the tower in the evening.

The translucent tower consists of 19 individual pieces manufactured out of glass fibre-reinforced epoxy resin. The complex geometry of the tower can be reduced through the repetition of individual elements to seven basic forms. The stability of the self-supporting GRP structure is ensured through the doublecurved geometry of the skin, reinforcing ribs in the upper section and restraints in the columns. The four columns take the form of tubes with flanges at their bases,

3

which are used to bolt the tower to the concrete foundation.

The individual elements were made manually in a hand lay-up process. This method made it possible to vary the thickness of the material as required. For the moulds, Styrofoam blocks were cut to shape with the help of a CNC milling machine and coated with a latex separating layer. The partial repetition of some

Assembly No. of parts - 19 Total surface area - 193.5 m2

of the elements made it possible to re-use the individual moulds. Despite being more expensive than polyester resin, epoxy resin was chosen for the laminate for its superior dimensional stability during the hardening process. This made it possible to produce GRP elements of different thicknesses. A further reason for choosing epoxy resin was its greater strength. The material thickness in the upper shelllike sections is 4.5 mm. The glass fibre context varies according to the load that has to be sustained. Wind loads proved to be the critical load case in the structural design of the elements. Additional layers of fibre have been incorporated for added strength along the returned edges of the elements as well as in the columns and the base flanges. The segments are both bonded and bolted to one another along their returned edges. With a total surface area of 193.5 m2, the tower weighs approximately 3000 kg. The tower was prefabricated in two halves before being transported to the site on the back of a large lorry. LEDs installed in small niches illuminate the tower at night in different colours.

4

130

D-Tower

1 Daytime view. 2 Detail: the consistent 45° angle of the glass fibre-reinforcement and the ­returned edges of the GRP moulded items in the flange areas are clearly visible. 3 At night the tower is ­illuminated with LEDs. 4 The D-Tower is made up of 19 individual elements.

1

Location Doetinchem, Netherlands Material Glass fibre-reinforced epoxy resin Completion 2004

131

PLASTICS AS BUILDING STRUCTURE

CASE STUDIES

2

Architecture NOX Architects, Lars Spuybroek Structural engineering Bollinger + Grohmann Ingenieure

The 12 m high tower sculpture is part of an interactive art project. Created together with the artist Q. S. Serafijn, the concept involved the local residents, who were asked to answer regular questionnaires. Their responses were then analysed by computer to determine the general emotional state of the community. The currently predominant emotion is represented by a colour that is then used to illuminate the tower in the evening.

The translucent tower consists of 19 individual pieces manufactured out of glass fibre-reinforced epoxy resin. The complex geometry of the tower can be reduced through the repetition of individual elements to seven basic forms. The stability of the self-supporting GRP structure is ensured through the doublecurved geometry of the skin, reinforcing ribs in the upper section and restraints in the columns. The four columns take the form of tubes with flanges at their bases,

3

which are used to bolt the tower to the concrete foundation.

The individual elements were made manually in a hand lay-up process. This method made it possible to vary the thickness of the material as required. For the moulds, Styrofoam blocks were cut to shape with the help of a CNC milling machine and coated with a latex separating layer. The partial repetition of some

Assembly No. of parts - 19 Total surface area - 193.5 m2

of the elements made it possible to re-use the individual moulds. Despite being more expensive than polyester resin, epoxy resin was chosen for the laminate for its superior dimensional stability during the hardening process. This made it possible to produce GRP elements of different thicknesses. A further reason for choosing epoxy resin was its greater strength. The material thickness in the upper shelllike sections is 4.5 mm. The glass fibre context varies according to the load that has to be sustained. Wind loads proved to be the critical load case in the structural design of the elements. Additional layers of fibre have been incorporated for added strength along the returned edges of the elements as well as in the columns and the base flanges. The segments are both bonded and bolted to one another along their returned edges. With a total surface area of 193.5 m2, the tower weighs approximately 3000 kg. The tower was prefabricated in two halves before being transported to the site on the back of a large lorry. LEDs installed in small niches illuminate the tower at night in different colours.

4

152

153

PLASTICS AS BUILDING STRUCTURE AND ENVELOPE

CASE STUDIES

Futuro

1 Futuro in the Centraal Museum in Utrecht. 2 The Futuro is assembled out of prefabricated modules.

3 Interior with radially arranged reclining seats. 4 Section and floor plan.

1

Location different locations worldwide Material GRP, PUR, polycarbonate Completion 1968

Architecture Matti Suuronen Structural engineering Yrjö Ronkka

Futuro, a house with just one room, is one of the few plastic houses to have been serially-produced and is regarded as a milestone in the history of plastic archi-

2

tecture. The story of the Futuro house began with a client’s desire for a ski chalet that could be heated quickly and was easy to erect in difficult-to-reach terrain.

The building needed to be able to be assembled or dismantled within two days and transportable with a helicopter to the desired location. The concept of the Futuro as a modular plastic house is largely a product of these requirements.

The form of the rotational ellipsoid with a circular plan can be attributed primarily to geometric considerations and production engineering requirements. Futuro consists of eight upper and eight lower individual segments, all of which are identical to enable them to be produced economically. With a diameter of 7.80 m, the house provides a net area of 50 m2. The house is borne by a slender circular steel

3 4

ring which is supported by four steel outriggers. The prototype was built in 1968 by Polykem Ltd. in Finland. The Futuro was exhibited alongside numerous other plastic houses at the first plastic housing exhibition in Lüdenscheid, Germany, in 1971.

The plastic envelope of the building is able to sustain and dissipate loads as a result of its shell structure and flexural bending. It consists of GRP sandwich elements, which reduce the weight of the structure and provide it with adequate thermal insulation. The overall weight of the plastic building is 2500 kg without contents or 4000 kg with contents. The rigid PUR foam core has grooves on its outer surface to allow condensation runoff. The individual segments are bolted together through stabilising ribs at the edges of the elements. The house is accessed through a trap door that folds out of the wall and when closed fits flush with the exterior of the building.

In practice, the Futuro served numerous different functions. A series of interior furnishings and furniture for different uses was specially developed and marketed. The standard furnishings included sanitary cell, kitchen unit, six radially arranged reclining seats, a double or two single beds and an oven grill. Manufacturing licences were sold to 25 countries around the world. Although precise figures are not available, an estimated 60 Futuros are thought to have been built. The Futuro rapidly advanced to become an iconic building of the avant-garde but like many other plastic houses found few admirers among the general public and did not sell as well as envisaged, not least because of its comparatively high price. It represents an experimental attempt to part with conventional notions of housing and develop a new form appropriate to a new material.

0

1

5m

152

153

PLASTICS AS BUILDING STRUCTURE AND ENVELOPE

CASE STUDIES

Futuro

1 Futuro in the Centraal Museum in Utrecht. 2 The Futuro is assembled out of prefabricated modules.

3 Interior with radially arranged reclining seats. 4 Section and floor plan.

1

Location different locations worldwide Material GRP, PUR, polycarbonate Completion 1968

Architecture Matti Suuronen Structural engineering Yrjö Ronkka

Futuro, a house with just one room, is one of the few plastic houses to have been serially-produced and is regarded as a milestone in the history of plastic archi-

2

tecture. The story of the Futuro house began with a client’s desire for a ski chalet that could be heated quickly and was easy to erect in difficult-to-reach terrain.

The building needed to be able to be assembled or dismantled within two days and transportable with a helicopter to the desired location. The concept of the Futuro as a modular plastic house is largely a product of these requirements.

The form of the rotational ellipsoid with a circular plan can be attributed primarily to geometric considerations and production engineering requirements. Futuro consists of eight upper and eight lower individual segments, all of which are identical to enable them to be produced economically. With a diameter of 7.80 m, the house provides a net area of 50 m2. The house is borne by a slender circular steel

3 4

ring which is supported by four steel outriggers. The prototype was built in 1968 by Polykem Ltd. in Finland. The Futuro was exhibited alongside numerous other plastic houses at the first plastic housing exhibition in Lüdenscheid, Germany, in 1971.

The plastic envelope of the building is able to sustain and dissipate loads as a result of its shell structure and flexural bending. It consists of GRP sandwich elements, which reduce the weight of the structure and provide it with adequate thermal insulation. The overall weight of the plastic building is 2500 kg without contents or 4000 kg with contents. The rigid PUR foam core has grooves on its outer surface to allow condensation runoff. The individual segments are bolted together through stabilising ribs at the edges of the elements. The house is accessed through a trap door that folds out of the wall and when closed fits flush with the exterior of the building.

In practice, the Futuro served numerous different functions. A series of interior furnishings and furniture for different uses was specially developed and marketed. The standard furnishings included sanitary cell, kitchen unit, six radially arranged reclining seats, a double or two single beds and an oven grill. Manufacturing licences were sold to 25 countries around the world. Although precise figures are not available, an estimated 60 Futuros are thought to have been built. The Futuro rapidly advanced to become an iconic building of the avant-garde but like many other plastic houses found few admirers among the general public and did not sell as well as envisaged, not least because of its comparatively high price. It represents an experimental attempt to part with conventional notions of housing and develop a new form appropriate to a new material.

0

1

5m