Architectural Expression A research on the expression of material Marjolein Marijnissen
Introduction 4 Compression and Tension 6 Notch and Knot 8 Expression of the Fabric 14 Wrap and Knot 16 Hole and Knot 20 Wood Joints 24 Slit and Knot 26 Cooperation 30 Mortise and Tenon 32 Final Design 40 Evaluation 48 Bibliography 50
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INTRODUCTION
Wooden tile battens and red and white fabric are the main ingredients of this project. The assignment is to make a model within a bounding box of 1 x 1 x 3.75 m3 only using tile battens and fabric. The assignment is about expression, tectonic and construction. The expression of both materials has to be analyzed trough the making of models. In this report we show the models we created in the last 8 weeks in a chronological order. With each model we reflect on the expression, the stability and the structural forces in the models. We will be looking for a combination of expression and structural cleanness.
COMPRESSION AND TENSION
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Wood is a material which is frequently used in architectural construction, in some countries it is even the number one building material. Wood has a small tensile strength and a greater pressure strength, therefore is most used stressed with compression. In contrast to wood, fabric is rarely used in construction. The material has no pressure strength but is capable for inclusion of tensile stress. To use both materials in a way that is best for them regarding their constructive characteristics, the wood will be stressed with pressure and the fabric with tensile.
NOTCH AND KNOT
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A small notch in the vertical direction. The fabric can be laced trough the notch and knotted, or the fabric can be laced trough multiple notch and knotted at the end. The notch ensures that the fabric remains in place in the horizontal direction
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The first model is based on the simplest example of a tensegrity, tensegrity is a structural system based on the differences between compression and tension, the two characteristics of respectively wood and fabric. Explained by Rene Motro (2003) “tensegrity system is a system in a stable self-equilibrated state comprising a discontinuous set of compressed components inside a continuum of tensioned components.� The model contains 3 wooden sticks which are floating in the tension of 6 fabric strips, resulting in a stable model. In the second model, an extra strip was tied around the middle of the 3 vertical fabric strips to increase the tension. The expression of the wood is ok, it shows the length. The expression of the fabric not visible in this model due to the use of small and tight strips.
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This tensegrity is a sequel on the previous one. The proportions are different and it is made with more sticks. The expression of a tile battens is one of a strong and quite rigid material, but with a certain flexibility due its dimensions. This flexibility is less clear in this example, because of the short length. Furthermore the fabric strips are wider in this model. It makes the fabric act more as fabric instead of thread, but on this scale and with this detailing it looks quite unorganized.
EXPRESSION OF THE FABRIC
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Even tough the previous models are made according to the structural characteristics of the materials wood and fabric, the expression of both the materials is not sufficient. The greatest deficiency in the expression can be found in the use of the fabric which looks more like a rope or a ribbon, a narrow strip, completely and tightly stretched. In the next models the fabric has to be used in bigger surfaces, so the fabric will have the scope for reaching its own shape. The manner in which fabric is able to find its own shape is in fact one of the great features of the expression of this material.
WRAP AND KNOT
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A small groove around which the fabric can be wrapped and knotted. The groove determines the location of the connection and does not interfere with the expression of the wood.
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A square frame made of tile battens, connected with strings of fabric. Fabric is connected to the wooden frame and is held up by a wooden batten, as a result the fabric is being stressed with tension. This tension stabilizes the wooden batten. Differences in the models are the location of the connection of the fabric and the wooden square, in the first models in the middle of the edges of the square, in the second model the connection is located at the corners of the square. The knots and clips, which make the models look a bit messy, are used to tighten the fabric. Even tough the models are surprisingly stable and the fabric is able to find it’s own shape, there is happening to much in these models. The knots and the clips, the wrap and knot connection with strings of fabric and the wooden batten in the middle don’t work as a whole model. Besides, the expression of the wood is subordinate or even absent in these models.
HOLE AND KNOT
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A hole through which the fabric can be pushed to be knotted on the other side. The hole keeps the fabric in place in both horizontal and vertical direction.
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A simple model created to investigate the expression of the fabric. Again compression and tension play their part in this model while it can only stand due to a equilibrium of the tension in the fabric. A great advantage of this model is the ease with which it is understandable, just 3 wooden battens and one triangular shaped plane of fabric. The fabric has just enough space to create its own shape and the tile battens have enough length. But in contrast to the previous models, the stability of this model is weak making it unusable to create a large model.
WOOD JOINTS
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In the previous models, fabric has been the connective element regarding the connection of different wooden elements. This way of connecting comes with all sorts of problems. In order to create the connection, fabric is used in small strips, which is contrary to the idea of the expression of the fabric. In addition, the connection is not very solid, the wood can still move within the connection, and it is difficult to realize the connection in the correct position. Wood joints are commonly used in architecture and have proven to be a solid solution when connecting multiple elements. The image on the left shows some of the commonly used wood joints. Using one of these instead of a connection created by fabric will solve a lot of the problems discovered in the previous models.
SLIT AND KNOT
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A small and long slit in the middle of the wooden batten trough which the fabric can be pushed and fixated on the other side. The slit keeps the fabric in place in both horizontal and vertical direction.
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In this model the main connection, in case of stabilization, is a lap joint. For this type of wood joint half of the wooden battens in removed at the location of the connection, allowing the two battens to precisely fit into each other. Because the connection is stressed in a direction perpendicular to the direction of the joint, connection remains stable. The expression of the wooden battens in the model is great, it shows the length without any interruption. The fabric expresses a lot of tension, in contrast to the other models there is no tension in the fabric in this model which makes it fake or like an ornament which is according to Adolf Loos (1908) the worst thing in life: “Ornamentation results in a waste of labour and an abuse of material as the aesthetic lifetime of an ornamented object is way less than it’s physical lifetime.�
COOPERATION
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Looking at the previously discussed wood joints, the mortise and tenon joint is the one with the most potential. It can be used the connect different wooden tile battens in the vertical direction which contributes to the length of the battens and therefore to the expression. With the mortise and tenon joint, there is also a way to connect the fabric to the wood within the same joint. And the fabric also cooperates with the wood to create the wood joint, it tightens the connection.
MORTISE AND TENON
A mortise and tenon joint connects two wooden battens with each other, the fabric through this joint tightens the joint and is the horizontal connection between multiple vertical elements.
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A horizontal frame of tile battens, connected with lap joints in which 6 vertical battens can be placed with a mortise and tenon joint. On the 6 vertical battens other wooden battens are placed connected with a mortise and tenon joint tightened by fabric slaps. An disadvantage of the model, due to the stress in the fabric slaps is the uncontrollable obliquity in the vertical direction. Even tough the model is stable, and a small obliquity contributes to the expression of the tile battens, there is to much uncontrollability in this model to use it on a larger scale.
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A small model created to try to reduce the wobbling and obliquity of the previous model with the same mortise and tenon connection. Instead of connecting all the vertical battens with one fabric plane, each of the vertical battens has its own fabric, woven around the battens in a vertical direction. The model gets more stable and less oblique but the expression of the fabric disappears due to the tight application.
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This model again tries to reduce the obliquity in the first mortise and tenon model. Again each of the vertical battens has its own fabric but now the fabric is not one ongoing piece over the entire vertical length but each mortise and tenon joint has its own small plane of fabric. An advantages of this way of using the fabric is the fact that the expression of the fabric is equally and properly on all sides of the connection. Also the obliquity is reduced.
FINAL DESIGN
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The mortise and tenon connection is one of the hardest in woodworking. The difficulty is the cutting of a rectangular hole in the wood, which requires special equipment or craftsmanship. Nevertheless, the connection is quite popular in wooden structures since ages. The connection is appreciated by its cleanness: one can hardly see how the connection is made. By applying the fabric between this joint, it becomes more clear what is going on inside the batten. One can say the detail shows transparency. Not through the use of translucent materials, but by the fabric which explains how the batten is cut and what happens inside the joint.This type of transparency is recognized by Colin Rowe and Robert Slutzky (1963) “Transparency may be an inherent quality of substance- as in a wire mesh or glass curtain wall, or it may be an inherent quality of organization... - ... one might distinguish between a literal and a phenomenal transparency.�
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One of the characteristics of tile battens is the length. As mentioned before, the expression of the tile batten becomes clearer at longer lengths. The previously discussed transparency created by the use of fabric in combination with the mortise and tenon joint also makes it possible to see a long tile batten instead of small pieces. To emphasize the mortise and tenon joint the wooden batten are rotated 90 degrees with each connection, as a result, the image of wath is going on inside the connection becomes more clear.
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Keywords belonging to the expression of the fabric are “tension”, “free formed” and “hanging”. Those of the tile battens are “compression” “length” and “bending”. The bending of the wood and the tension of the fabric can both be expressed due to a little obliquity in the vertical tile battens. It shows that the fabric is holding the different vertical battens together with tension and the bending of the wooden tile battens is being exaggerated by the obliquity.
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By using multiple layers of fabric, the mortise and tenon joint gets tighter, resulting in a more controllable an stable structure. To demonstrate that it takes effort to achieve this stability different colors of fabric are used in order to emphasize that a lot of tension is necessary the create a tight joint.
EVALUATION
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In contrast to normal architectural projects in witch drawing is the most important media and models are made in a small scale, with materials that do not correspond to reality this project was based on working with the real, and large materials and designing through models. This way of designing is very instructive, because all models are made with the real material and on a large scale, the models tell, more than usual, about the expression of the model. For example,if our models was made as a scale model, the expression of the tile battens would have been wrong because of the short length and the fabric would have had less space to create it’s own shape. Also drawings would have undermine the expression of the design, the imperfections of the wood and again the shape of the fabric would not correspond with reality. In addition to the expression of the large scale models, the building of them has also been very instructive. Where glue normally solves all the problems regarding the connections in a small scale model, the large scale model asked for connections with the real wood and fabric, it makes you think about the details and the way it can be build.
BIBLIOGRAPHY
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Loos, A. (1908). Ornament and Crime. Innsbruck, reprint Vienna, 1930 Motro, R. (2003). Tensegrity, Structural Systems for the Future. Kogan Page Limited, London, United Kingdom. Rowe, C. Slutsky, R. (1963). Transparency: Literal and Phenomenal. Perspecta, Basel, Switzerland