Making Blobs with a Textile Mould Arno C.D.Pronk!and Rogier Houtman2 1 Department of Architecture,Building and Planning Technical University of Eindhoven P.O.box 513,NL-5600 MB Eindhoven,NL a.d.c.pronk@bwk.tue.nl http://www.blob.tue.nl 2 Department of Civil Engineering Laboratory of Building Engineering Delft University of Technology P.O.box 5048,NL-2600 GA Delft NL Tentech Design Engineering P.O.box 619,NL-2600 AP Delft NL rogier@tentech.nl http:/www.tentech.nl Summary.In the last decade compler buildings i.e.with unregular curved surfaces have been designed..The subject of this paper is the construction of those compler buildings.One of the main characteristics of a membrane structure is its geometrical complerity,which can be seen in multiple curved surfaces and complicated connection elements.Modern sophisticated computer technologies can be used to produce easily these compler three-dimensional shapes out of flat strips of fabric.Due to a lack of suitable production methods the erpression of the natural stress flow in supporting and connecting (rigid)structural elements is difficult.This paper assumes that it is possible to achieve the architectural desired free forms by manipulation of structural membranes.To prove that it is possible to achieve the architectural desired free forms different cases are described in which this technique is used.The first case describes the design of an indoor Ski run.The second and third case describes the building of a lightweight stage covering and an art pavilion.In all the three cases physical models have been used in the design phase.The structural design of the membrane mould has been engineered with the program easy.The rigidized structures have been analyzed using different FEM programs for each case.The transformation of a form- active structure (membrane)into a surface-active structure has been researched to make domes ore dome-like structures. Key words:Blobs,textile mould,free geometry architecture,tensile structures, pneumatic structures,formfinding,structural optimisation 305 E.Onate and B.Kroplin (eds.).Textile Composites and Inflatable Structures,305-322. 2005 Springer.Printed in the Netherlands
Making Blobs with a Textile Mould Arno C.D. Pronk1 and Rogier Houtman2 1 Department of Architecture, Building and Planning Technical University of Eindhoven P.O. box 513, NL-5600 MB Eindhoven, NL a.d.c.pronk@bwk.tue.nl http://www.blob.tue.nl 2 Department of Civil Engineering Laboratory of Building Engineering Delft University of Technology P.O. box 5048, NL-2600 GA Delft NL Tentech Design & Engineering P.O. box 619, NL-2600 AP Delft NL rogier@tentech.nl http:/www.tentech.nl Summary. In the last decade complex buildings i.e. with unregular curved surfaces have been designed. . The subject of this paper is the construction of those complex buildings. One of the main characteristics of a membrane structure is its geometrical complexity, which can be seen in multiple curved surfaces and complicated connection elements. Modern sophisticated computer technologies can be used to produce easily these complex three-dimensional shapes out of flat strips of fabric. Due to a lack of suitable production methods the expression of the natural stress flow in supporting and connecting (rigid) structural elements is difficult. This paper assumes that it is possible to achieve the architectural desired free forms by manipulation of structural membranes. To prove that it is possible to achieve the architectural desired free forms different cases are described in which this technique is used. The first case describes the design of an indoor Ski run. The second and third case describes the building of a lightweight stage covering and an art pavilion. In all the three cases physical models have been used in the design phase. The structural design of the membrane mould has been engineered with the program easy. The rigidized structures have been analyzed using different FEM programs for each case. The transformation of a formactive structure (membrane) into a surface-active structure has been researched to make domes ore dome-like structures. Key words: Blobs, textile mould, free geometry architecture, tensile structures, pneumatic structures, formfinding, structural optimisation 305 E. Oñate and B. Kröplin (eds.), Textile Composites and Inflatable Structures, 305–322. © 2005 Springer. Printed in the Netherlands
306 Arno C.D.Pronk and Rogier Houtman 1 Blobs In 1994 K.Michael Hays [10]writes that in reaction to fragmentation and contradic- tion there is a new movement in architecture,which propagates a combination not only of forms,but also between different media like film,video,computers,graphics mathematics and biology.He recognizes that architecture is influenced by the devel- opment of an increasing complexity of information and communication is changed into information and media.This has lead to a development that is being referred to as blob architecture (Figs.1,3).The characteristics of blobs are:smoothness, irregularity and a double curved skin. Fig.1.by Michael Bittermann Fig.2. Fig.3. Modeling by means of nylon stockings and balloons 2 Blobs with a Textile Mould The similarity between form active structures,like tent-and pneumatic structures on the one hand and blobs on the other hand is so striking that it is obvious to try to make blobs with techniques,that are being used for constructing tent-and pneumatic structures. In the past numerous possibilities have been examined.Frei Otto for example has demonstrated the possibilities of influencing the form of pneumatic structures by stretching nets and cables over them.Another possibility of manipulating a tensile form is the combination of cloth and a pneumatic structure into a blob design.An example is the floating theatre at the Expo 1970 in Osaka designed by Yutaka Mu- rata.One of the latest examples of transforming the shape of a pneumatic structure
306 Arno C.D. Pronk and Rogier Houtman 1 Blobs In 1994 K. Michael Hays [10] writes that in reaction to fragmentation and contradiction there is a new movement in architecture, which propagates a combination not only of forms, but also between different media like film, video, computers, graphics mathematics and biology. He recognizes that architecture is influenced by the development of an increasing complexity of information and communication is changed into information and media. This has lead to a development that is being referred to as blob architecture (Figs. 1,3). The characteristics of blobs are: smoothness, irregularity and a double curved skin. Fig. 1. by Michael Bittermann Fig. 2. Fig. 3. Modeling by means of nylon stockings and balloons 2 Blobs with a Textile Mould The similarity between form active structures, like tent- and pneumatic structures on the one hand and blobs on the other hand is so striking that it is obvious to try to make blobs with techniques, that are being used for constructing tent- and pneumatic structures. In the past numerous possibilities have been examined. Frei Otto for example has demonstrated the possibilities of influencing the form of pneumatic structures by stretching nets and cables over them. Another possibility of manipulating a tensile form is the combination of cloth and a pneumatic structure into a blob design. An example is the floating theatre at the Expo 1970 in Osaka designed by Yutaka Murata. One of the latest examples of transforming the shape of a pneumatic structure
Making Blobs with a Textile Mould 307 is the tensile structure of the Swiss pavilion(Figs.4,5)at the Expo 2002.The edges of the structure are transformed by using bending stiff elements.The connection with nature is obvious if we realize that a human body can be seen as a membrane (the skin)stretched over bones (wire-frame)and muscles (pneumatic structure). Fig.4. Fig.5. Nouvelle DestiNation Bundespavillon,Swiss Expo 02(Eckert Eckert Architekten) Fig.6.Rigidized inflatable structure (A.Pronk) 3 Form-Active/Surface Active In the open-air theatre in Soest a pneumatic structure was used as a mould.This mould was then rigidized,which resulted into a bent stiff beam that was combined with cloth.The result was a tensile structure.This technique was then studied.The purpose was to use this technique to realize complete buildings. Heinz Isler has already demonstrated that it is possible to rigidize a pneumatic mould to construct buildings.The same principle is used in aerospace engineering for realizing antennas and space habitats.(In Soest the same principle is used to construct architectural shapes.)The surface of the building was not the result of the mechanics but the result of an architectural design process.At the Technical University of Delft and Eindhoven a group has been formed that has taken on the challenge of finding a way to realize blobs by means of transforming and rigidizing
Making Blobs with a Textile Mould 307 is the tensile structure of the Swiss pavilion (Figs. 4,5) at the Expo 2002. The edges of the structure are transformed by using bending stiff elements. The connection with nature is obvious if we realize that a human body can be seen as a membrane (the skin) stretched over bones (wire-frame) and muscles (pneumatic structure). Fig. 4. Fig. 5. Nouvelle DestiNation Bundespavillon, Swiss Expo 02 (Eckert Eckert Architekten) Fig. 6. Rigidized inflatable structure (A. Pronk) 3 Form-Active/Surface Active In the open-air theatre in Soest a pneumatic structure was used as a mould. This mould was then rigidized, which resulted into a bent stiff beam that was combined with cloth. The result was a tensile structure. This technique was then studied. The purpose was to use this technique to realize complete buildings. Heinz Isler has already demonstrated that it is possible to rigidize a pneumatic mould to construct buildings. The same principle is used in aerospace engineering for realizing antennas and space habitats. (In Soest the same principle is used to construct architectural shapes.) The surface of the building was not the result of the mechanics but the result of an architectural design process. At the Technical University of Delft and Eindhoven a group has been formed that has taken on the challenge of finding a way to realize blobs by means of transforming and rigidizing
308 Arno C.D.Pronk and Rogier Houtman pneumatic structures.As a first study a model has been build that consists of bal- loons and a wire-frame that is placed in a nylon stocking (Fig.2).It is possible to make many different forms with this technique.After modeling the shape a polymer resin is applied(Fig.3).This physical model can be analyzed by means of a finite element computer program that looks at the active behavior of the surface of the structure.The input for the program is generated by a 3d scan(Fig.17). 4 Stage Covering for an Open-Air Theatre 4.1 Introduction This semi-permanent membrane structure covers the stage of the open-air theatre in Soest (the Netherlands)Fiber reinforced plastics are used for the production of a structural optimized and therefore lightweight and complex arch shaped struc- ture.By using an inflatable mould the arch could be produced more economically (30%cost reduction).In the production the vacuum injection method is utilized for stiffening flexible fibers. The owner of the Soest open-air theatre asked for a protection against bad weather for the stage.Therefore we suggested covering it with a lightweight mem- brane structure.A suspended membrane floats above the stage,so that visual rela- tions with the natural environment are still preserved(Fig.7).Outside the theatre- season the structure could partially be dismantled in this way the environment that is protected by national government is not visually disrupted.Two guyed columns are part of a dismantling system and could be used for hoisting the temporary membrane.The form of the spatial membrane is,beside the indirect support of the columns,the result of an arch.Because of this arch the protective area of the cov- ering is increased and additional curvature in the membrane is improved (Fig.8). In this way the membrane structure is a combination of two highpoint surfaces and an arched surface,the stage covering works like a tensegrity structure.The columns and arch transmit compressive loads.Both the Tensile loads and the stabilization of the whole structure are transmitted and organized by the prestressed membrane and cable structure. Fig.7.The stage covering for the Fig.8.An arched beam ensures an Soest open-air theatre in the Nether- increase of the protective area and the lands(H.Werkman) curvature of the membrane structure
308 Arno C.D. Pronk and Rogier Houtman pneumatic structures. As a first study a model has been build that consists of balloons and a wire-frame that is placed in a nylon stocking (Fig. 2). It is possible to make many different forms with this technique. After modeling the shape a polymer resin is applied (Fig. 3). This physical model can be analyzed by means of a finite element computer program that looks at the active behavior of the surface of the structure. The input for the program is generated by a 3d scan (Fig. 17). 4 Stage Covering for an Open-Air Theatre 4.1 Introduction This semi-permanent membrane structure covers the stage of the open-air theatre in Soest (the Netherlands) Fiber reinforced plastics are used for the production of a structural optimized and therefore lightweight and complex arch shaped structure. By using an inflatable mould the arch could be produced more economically (30% cost reduction). In the production the vacuum injection method is utilized for stiffening flexible fibers. The owner of the Soest open-air theatre asked for a protection against bad weather for the stage. Therefore we suggested covering it with a lightweight membrane structure. A suspended membrane floats above the stage, so that visual relations with the natural environment are still preserved (Fig. 7). Outside the theatreseason the structure could partially be dismantled in this way the environment that is protected by national government is not visually disrupted. Two guyed columns are part of a dismantling system and could be used for hoisting the temporary membrane. The form of the spatial membrane is, beside the indirect support of the columns, the result of an arch. Because of this arch the protective area of the covering is increased and additional curvature in the membrane is improved (Fig. 8). In this way the membrane structure is a combination of two highpoint surfaces and an arched surface, the stage covering works like a tensegrity structure. The columns and arch transmit compressive loads. Both the Tensile loads and the stabilization of the whole structure are transmitted and organized by the prestressed membrane and cable structure. Fig. 7. The stage covering for the Soest open-air theatre in the Netherlands (H. Werkman) Fig. 8. An arched beam ensures an increase of the protective area and the curvature of the membrane structure
Making Blobs with a Textile Mould 309 Due to its position in the audience's view and its proportions,the arch con- tributes in certain extent to the architecture of the structure.Therefore,special attention is given to the elaboration of the structural arch.The arch'dimensions exceed several times the thickness of the membrane and the cables.To avoid an abrupt change between the 'thick'arch and 'thin'membrane,a tapered arch sec- tion is desirable.The result is a conical arch.Because the mass of the arch would influence the membrane shape,a lightweight construction is necessary.This conical arch,which is characterized by geometrical complexity due to multiple curvature, and the necessity of a lightweight structure.asked for the use of an unconventional construction material and production technology. 4.2 Materialisation Conventional construction materials like steel and aluminium and accompanying production technologies are not suitable for making lightweight multiple curved arches.The material properties and production methods of fibre reinforced plastics (FRP)matches the arch requirements.Some advantages of fibre reinforced plastics are:rigid and lightweight construction possibilities,fatigue resistance,chemical and corrosion resistance,freedom in design and form and the possibility to integrate parts.Important disadvantages are the cost prices of material,mould,production (labour)and engineering.In the case of complex shapes,for example a conical arch, approximately 50%of the production costs consist out of model costs.Therefore an effective way of cost reduction is to decrease the mould price. 4.3 Geometrical Complexity and Production Technology Through the utilisation of a pneumatic mould the cost price of the arch is reduced with 30%(Fig.9).In the production of the mould the same computer applications (EASY,FEM-based software)and production technologies are used as those used for the development of the membrane structure.After modelling and formfinding in EASY cutting patterns are generated and used for the production of the mould. The internal over-pressure ensures the rigidity of the inflatable mould.The general dimensions,like the distance between the supports,are controlled by an auxiliary structure (Fig.10). 100 Fig.9.Pneumatic mould supported Fig.10.General dimensions of the by the auxiliary structure (Ten- mould tech/Buitink Zeilmakerij)
Making Blobs with a Textile Mould 309 Due to its position in the audience’s view and its proportions, the arch contributes in certain extent to the architecture of the structure. Therefore, special attention is given to the elaboration of the structural arch. The arch’ dimensions exceed several times the thickness of the membrane and the cables. To avoid an abrupt change between the ’thick’ arch and ’thin’ membrane, a tapered arch section is desirable. The result is a conical arch. Because the mass of the arch would influence the membrane shape, a lightweight construction is necessary. This conical arch, which is characterized by geometrical complexity due to multiple curvature, and the necessity of a lightweight structure, asked for the use of an unconventional construction material and production technology. 4.2 Materialisation Conventional construction materials like steel and aluminium and accompanying production technologies are not suitable for making lightweight multiple curved arches. The material properties and production methods of fibre reinforced plastics (FRP) matches the arch requirements. Some advantages of fibre reinforced plastics are: rigid and lightweight construction possibilities, fatigue resistance, chemical and corrosion resistance, freedom in design and form and the possibility to integrate parts. Important disadvantages are the cost prices of material, mould, production (labour) and engineering. In the case of complex shapes, for example a conical arch, approximately 50% of the production costs consist out of model costs. Therefore an effective way of cost reduction is to decrease the mould price. 4.3 Geometrical Complexity and Production Technology Through the utilisation of a pneumatic mould the cost price of the arch is reduced with 30% (Fig. 9). In the production of the mould the same computer applications (EASY, FEM-based software) and production technologies are used as those used for the development of the membrane structure. After modelling and formfinding in EASY cutting patterns are generated and used for the production of the mould. The internal over-pressure ensures the rigidity of the inflatable mould. The general dimensions, like the distance between the supports, are controlled by an auxiliary structure (Fig. 10). Fig. 9. Pneumatic mould supported by the auxiliary structure (Tentech/Buitink Zeilmakerij) Fig. 10. General dimensions of the mould