APPLYING TEXTILE PRINCIPLES ON A BUILDING SCALE
A PROJECT BY YVES WEINAND & MARKUS HUDERT
This thesis project proposes to investigate a new family of timber constructions based on the logic and principles of man-made fabrics. In fabrics, as well as in basketry, the coherence of the yarn elements is governed by friction. Additionally, the basic materials are, in principle, available with infinite length. This radically changes on a building scale. Whereas there might be a possibility of building structures based on friction up to a certain size, it is certain that one needs to consider material limitations, for instance in length, and how to deal with them. One has to address the question of how to translate textiles into building structures without betraying their basic principles. Can textile principles be transformed into something new, something that is more than just a mere literal metaphor of weaving? The consequences of such an approach might result in something that is not immediately recognized as a textile structure, but yet adapts its logic in the most stringent way.
A PROJECT BY
YVES WEINAND is a belgium achitect and civil engineer, having his research department in Liège, Belgium, and he’s also a professor at l’Ecole polytechnique in Lausanne, Switzerland. MARKUS HUDERT is a german architect living in Lausanne.
Practical and material orientated academic research has become increasingly important for architectural practice. This is due to several reasons. First of all, it contributes to contemporary concepts in architecture and improves their implementation. Todayâ€™s architects are looking for a deeper understanding of technical and technological questions related to architecture: technology, construction methods as well as structural considerations are no longer seen as bothersome necessities, as it was often the case in the past. The importance of those aspects and the potential of including them in the architectural design process as active stimulus are largely recognized. Itâ€™s the limitations in time and capacities that more often than not confound the realisation of such ambitions. Academic research can fill this gap and provide architectural practices with the necessary resources.
The IBOIS, the laboratory for timber construction of the EPFL, is directed by Professor Yves Weinand, engineer and architect, since October 2004. The laboratory undertakes research and teaching within the framework of the civil engineering section of the ENAC.
Research is in charge for finding answers to one of the biggest architectural challenges of our time, namely sustainable building. Societyâ€™s burgeoning awareness of the urgent need to use renewable materials for building construction is undeniable and has become an important parameter for architectural production. As a result, timber constructions experience a new popularity and the importance of research on timber increased. The potential of this research becomes evident with some of the latest developments and innovations in this domain. Cross laminated timber panels open up new dimensions for massive timber construction and prefabrication in context with the digital chain. Technologies like wood welding or the densification of wood create new possibilities not only for architecture but also for furniture and product design. Timber as building material is therefore capable of satisfying both the demands of contemporary architecture as well as the requirements of sustainable building. By doing so, a new generation of timber structures could be created.
« Timber is coming to the fore as a contemporary construction material. Not only sustainable, its suppleness, adaptability and strenght make it highly attractive for experimental designers. Yves Weinand founded the interdisciplinary timberfabric research at IBOIS, the Laboratory for Timbe Fabric, at the Ecole Polytechnique Fédérale de Lausanne (EPFL), in order to fully explore innovative timber construction techniques. Here Yves Weinand and Markus Hudert describe the Textile Module, which Hudert developed, in order to investigate timber’s ability for social behaviour’, or greater structural strength, one woven into a textile-like form. » 11
Textiles are interesting from both a structural and an architectural point of view. Their patterns and textures, created by the interworking of yarn elements, are not only highly appealing on an aesthetical level, they also possess load bearing qualities. The research project Structural Timber Fabric: Applying Textile Principles on Building Scale sets out to investigate this potential and proposes to develop a new family of timber constructions based on the logic and principles of textile techniques. In this context, and within the scope of several case studies, one of the core objectives is to create an innovative structural system with concise aesthetic, spatial and structural qualities. Thus, the proposal addresses important challenges at the frontiers of the fields of architecture and civil engineering.
Entangled fibre in felt, yarn structures of knitted and woven fabric.
During the process of analyzing textile techniques regarding their suitability for large scale application, it became clear that, apart from the commonly known techniques such as felting, knitting, braiding and weaving, an immense amount of variants exists. This insight triggered an adjustment in the direction of investigation. Instead of aiming at a comprehensive overview of existing techniques, the quest for a least common denominator of textiles was launched. This quest resulted in the finding that practically all textile structures can be reduced to one in principle identical unit cell. This unit cell acts as a kind of basic module and consists of two intercrossing threads.
FELTED FIBERS (simple fibre assembly) example: -felt -paper
INTERWORKED ELEMENTS Primary Textile Techniques
example: -mesh, fabrics -knitting, crocheting
Advanced Textile techniques
example: -braiding -plaiting (with active systems)
CHARACTERISTICS OF WOVEN FABRICS - Application as structure -
Weaving Loom; Source: Seiler-Baldinger 1994
Plain weave pattern; Source: Seiler-Baldinger 1994
Twill weave pattern; Source: Seiler-Baldinger 1994
COMPARISON PLAIN WEAVE AND TWILL WEAVE PATTERN
IDENTIFYING A LEAST COMMON DENOMINATOR
Exploring the variety and diversity of textile fabrics - expansive approach.
Unit cell in woven fabrics
Defining the Least Common Denominator.
Unit cell in knitted fabrics
Source: Textile structural composites, T.-W. Chou and F.K.Ko, 1989
In a following step, the principle of this unit cell was brought to large scale by interbraiding two strands of glue laminated timber. By doing so, the researchâ€™s first promising outcome, the so-called Textile Module, was produced. It shows how the use of a particular textile technique of assembly, together with the properties of a specific material, can lead towards a particular and structurally efficient construct, whose geometry is automatically generated by the process of assembly.
Model of the textile module, top view.
Model of the textile module, perspective view.
DEVELOPING STRUCTURAL FABRIC
FROM TEXTILE FABRIC TO TIMBER FABRIC
MULITPLE ARCHS LINEAR CONNECTION ADDITIONAL PERPENDICULAR ELEMENTS
SUPERPOSITION OF ARCHS
22 Module height
Additionally, it commands of exceptional behaviour when put under pressure: the structure becomes longer and flatter but in the same time, the sectional triangle in the middle of the module narrows, becomes higher and therefore stiffens the structure. One of the structural advantages of textiles is the already described system effect: they are made up of many basic elements that are interconnected and work together as a whole. Therefore the failure of one or several of the basic elements doesnâ€™t lead to the failure of the whole structure. In order to achieve a similar effect on building scale, it is likewise necessary to create a structure that is composed of a multitude of elements.
At present, the research work focuses on how this can be accomplished by using the Textile Module as a basic element, or, in other words, as unit cell of such a structure. The most obvious method of doing so is to combine several modules in a linear way, which creates an arch like structure. A sequence of several of those arches can then be combined again to form a structure similar to a vault. The disadvantage of this approach is that the arch elements stay independent from each other. Thereâ€™s no continuity in the cross direction. A possible reaction to that is the addition of elements perpendicular to the arches which also improve the overall structural capacities by large amounts. A second possibility is to create a fabric that is continuous in both directions. This becomes possible by shifting the basic modules and increasing the distance between them. However, this can also lead to geometrical complications in the total of the structure. All the same this is a promising direction for future examinations and further development.
A large scale prototype of the Textile Module was developed in the context of the exhibition Timber Project, which was on display from February 25th to May 31st at the Archizoom exhibition space. In the forefront of this, the assembly of the structure was simulated with the FEM software Abaqus. By doing so, the initial stress, caused by the bending of the panels, could be identified. Furthermore, the structural behaviour of the joint panels was examined. Result- ing from this study, the dimensions and proportions of the timber panels were determined.
In a following step, the structural performance of the Textile Module was compared to an arch composed of the same quantitiy of material. In this test, the performance of the Textile Module was considerably better than the one of the arch. For the continuation of this research, the work with FEM software will be very important. It presents a promising approach to draw near a geometrical description of the Textile Module and the computation of its structural properties. Apart of the singular Textile Module, other configurations will be simulated and calculated in the near future.
SOURCES: http://ibois.epfl.ch/files/content/ sites/ibois2/files/shared/recherche/ timber%20fabric.pdf http://infoscience.epfl.ch/record/165971/files/SWST2010.pdf
book & researches by Floriane Misslin