“Thinking by Modeling”- Frei Otto Exhibition

In November 2016, the ZKM – Zentrum fuer Kunst und Medien – Centre for Arts and Media – in Karlsruhe, Germany, inaugurated its exhibition on the works of Frei Otto entitled “Frei Otto – Thinking by Modeling” (November 05, 2016 – March 12, 2017): an exhibition unprecedented in terms of conception and extent, curated by Prof. Georg Vrachliotis. In the year before, Frei Otto had passed away, while in the same year he had been awarded the prestigious Pritzker Prize for architecture. As a result, the attention  of architects, engineers and designers worldwide has been refocused on the  personality, the works and the achievements of Frei Otto. The opening of the exhibition was widely picked up, attracted a lot of visitors and comes along with several “special events”, one of them being a symposium which will be held on January 26-27, 2017.

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© ZKM Zentrum für Kunst und Medien, Foto: Grünschloss

The works of Frei Otto and his research teams play an active role in current design of architecture and engineering. They are often referred to when lightweight structures or bionically inspired designs are discussed. The current attention on Frei Otto,his insights and merits should be interpreted as contributions to our heritage, prospect and responsibility. His exclamation “Stop building the way you build!“, formulated during a lecture in 1977 [1], is still reverberating. This outcry can be taken as an inspiration for many disciplines, be it architecture, engineering, biology or social sciences.

Frei Otto and the Institute of Lightweight Structures in Stuttgart

The establishment of the “Institute of Lightweight Structures” at the University of Stuttgart, Germany, was a starting point to a “time line” of lightweight structures at this location. Fritz Leonhardt called Frei Otto, who was at that time living and working in Berlin, to Stuttgart University. Fritz Leonhardt (1909 – 1999) was the designer of the Stuttgart television tower which was the first of its kind being constructed in reinforced concrete, the author of books dealing with “aesthetics” of bridges, and pioneer in the field of designing structures in reinforced concrete. Leonhardt had published his thoughts about lightweight structures as a “demand of our times” in 1940 [2], a time facing material scarcity during a devastating war which had been triggered by Nazi-influenced Germany. The lack of material, or the restriction to a certain kind of material, can be taken as a source of inspiration for lightweight construction: Eladio Dieste, Felix Candela and Robert Maillart developed their unique aesthetics by this kind of limitation. Fritz Leonhardt was aware of this special quality and in that spirit he called Frei Otto to be Professor at the the Institute of Lighweight Structures IL at Stuttgart University.

During this time, Frei Otto was dealing with the detailed design of the German pavilion for the Expo Montreal in 1967, a piece of architecture which was path breaking in many ways. A test building of the Expo roof, prototype of a cable net structure, was to become the place of location of the IL.

Joerg Schlaich was the successor of Fritz Leonhardt as Professor at the University of Stuttgart. Werner Sobek assumed the chair of Frei Otto at the Institute of Lightweight Structures in 1994. In 2001, he was additionally appointed as successor to Joerg Schlaich’s Chair. The two chairs were merged to become the “Institute of Lightweight Structures and Conceptual Design” ILEK. In 2015, Werner Sobek was awarded the “Fritz Leonhardt Prize”, a distinction awarded every three years to an engineer in recognition of outstanding contributions to the area of structural engineering. In a very emotional speech, Sobek stated his view of the necessity of lightweight structures, based on very descriptive and startling numbers [3].

The circle is closing: the need for lightweight structures, be they named material-efficient or low-carbon-footprint, is even more relevant in the beginning of the 21st century. Frei Otto initiated a center of knowledge which reached out to the world.

“Thinking by Modeling” – the exhibition

The exhibition is set up in two large-scaled rooms of the “ZKM” (Zentrum fuer Kunst und Medien – Center for Arts and Media) museum in Karlsruhe. The building itself was originally built as a munition factory and is a protected monument with classical elements of industrial architecture. It hosts the ZKM since 1997.

The city of Karlsruhe is also the location of the “saai” (Suedwestdeutsches Archiv für Architektur und Ingenieurbau – Southwest German Archive of Architecture and Engineering), where Frei Otto’s works have been archived after his passing away.

Due to the initiative of Prof. Georg Vrachliotis, Professor at the KIT Karlsruhe, this impressive exhibition has been realized.

The exhibition is constituted by four elements: model landscape, open archive, cosmos, and projection.

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How to describe the esthetics of structural surfaces? (1/2)

It has been said that the work of Frei Otto (Germany, 1912-2015) has a sculptural quality to it [1]. Although Frei Otto’s parents were sculptors, he insisted that the shapes he produced were rigidly grounded in the laws of physics [1], and was very reluctant to describe their aesthetic value. This observation hints at the questions that this paper starts to address, namely how can one describe the aesthetics of a curved structural surface?

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Structural Membrane Form Finding Study – Image Credit Frei Otto

It is observed that structural aesthetic critique is a little practiced discipline. In engineering education, students generally are not encouraged to express their emotions about the built environment, and are not frequently encouraged to develop an enthusiasm for visual experiences [2]. Beauty seems to engineers such a vague concept, hard to define accurately to others.

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Our ultimate top 20 book list for 2016

As the holidays are approaching and as your loved ones – yet again – run out of inspiration for your holiday gift… the Form Finding Lab comes to the rescue. We present you a list of our favorite books on engineering, architecture and anything in between.

Happy holidays,

The Form Finding Lab.

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Compiled by Tim Michiels, with contributions of Sigrid Adriaenssens, Victor Charpentier, Demi Fang, Andrew Rock and Olek Niewiarowski

What I am thinking: the engineer and architect Marc Mimram

Marc Mimram is a celebrated French engineer and architect with projects in France and around the globe. He generously shares with us his ideas on bridge design in conversation with PhD candidate Victor Charpentier.

Victor Charpentier (VC): Marc Mimram, you are both an architect and engineer. Yet you have said that when you are given a project, the greater part of the inspiration for the initial spark comes from a third field, which is study of the landscape and geography. Can you explain why this is so important to you and how this affects your designs?

Marc Mimram (MM): Each project should be specific. It has to be depending of the situation where it take place.

To become a coherent project, it has to be related to the geography, the horizon. It should express the relation to the ground, to the sky, to the landscape considered as a geography informed by history.

In that case the structural project can take roots in the reality and forget the abstract equation of strength of materials to express gravity, the movement of forces, the movement of light; being part of the situation, part of the world, belonging to the site.

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Whong Sheng Da Dao Bridge in Sino Singapour, Tainjin Eco-City (China). (Image provided by Marc Mimram)

Advanced technologies have allowed structural form finding to become an integral part of many recent design projects. How do you add your personal, creative touch to a process that can become largely computational? What are your thoughts on the role of this method for the future of engineering design?

MM: The process of computational form finding is a method of optimization and as such, it follows the development of the project. It is obviously important to develop the project with frugality but the rational process of development can be plural and the choice has to be related to the specific situation, taking into account the landscape, the topography but also the economical situation, the knowledge, the development of local craftsmanship, the local materials.

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Liu Shu footbrigde in the City of Yangzhou with a variable width of 3 to 5.7 m (Image provided by  Marc Mimram)

In the past decade, many of your larger bridge projects have been built in Asia or in North Africa in part because of more local design freedom. In your opinion, are there too many inhibitions in the field of construction in western countries? What could be improved to bring creativity and exploration back to construction while at the same time maintaining the high standards of safety?

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Keeping Sharks and Rocks Away: A few of the countless applications of nets

 

 

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Some of Frei Otto’s sketches from the Institute for Lightweight Structure’s “Netze in Natur und Technik” (1975)

 

Nets have been a perennial source of fascination in fields as diverse as engineering, architecture, art, and mathematics. As such, thinkers in these fields have come up with a dazzling array of applications and uses for nets, which force us to expand upon our preconceptions of what nets are and what they can be used for.

Pause for a moment – how many applications of nets can you think of? The late Frei Otto had a well-known interest in nets and their applications to structural engineering. A flip through a 1975 publication from the University of Stuttgart’s Institute of Lightweight Structures (of which Frei Otto was a director) reveals pages of sketches (see above and below) on net elements, forms, typologies, and applications. The applications range from the prosaic (tennis racquet, hammock) to the extraordinary (stadium roofs, bridges), to the bizarre (airplane barrier, anti-U-boat net).

Personally, my research concerns underwater cable nets, and I’m currently assisting with the design of a net with a very unique application: preventing shark attacks.

La Reunion, a French island in the southern Indian Ocean, is renowned for its surfing and beautiful beaches. However, this paradise has been suffering from a surge in shark attacks in recent years. Since 2011, there have been nineteen attacks, of which seven were fatal. The attacks peaked in 2013, which forced authorities to temporarily ban aquatic activities. As a result, the island’s economy has been strained, with beach-front businesses bearing the heaviest losses.

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“Net Out Of Order,” reads a sign on the empty Boucan Canot beach.

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Grow strong and live beautifully: Colombian bamboo structures

While the new group of senior students are getting up to speed with their senior theses, we look back in this weeks blog post on the work of Russell and Lu Lu in Colombia.

In March 2016 Russell Archer (’16) and Lu Lu (‘16) traveled to the city of Cali, Colombia and the coffee region (Spanish: Eje Cafetero) north of Cali where they visited a variety of structures made of south American bamboo species Guadua angustifolia, known as the “vegetable steel” for its impressive strength. These structures range from traditional vernacular houses, roofs and bridges designed by Simón Vélez, to classrooms designed by Andres Bappler. Russell and Lu were inspired by both the abundance and the level of sophistication found in these bamboo buildings.

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Left Image: Russell (right) and Lu (left) standing in front of a huge bamboo forest near a school building construction site at UTP campus in Pereira, Colombia. Right Image: A vernacular bamboo chair in a local bar.

Visiting Cali, Colombia and the surrounding regions showed us how bamboo is deeply ingrained as a part of daily life in Colombia, from chairs and fences to larger scale bridges and buildings. Much of bamboo design is driven by designer’s and builder’s knowledge of the material properties. This knowledge has expanded over generations and has added to the scale of the structures that can now be achieved. At the Universidad Technolόgica de Pereira (UTP), an arch bridge designed by Simón Vélez (http://www.simonvelez.net/) traverses a roadway connecting two parts of the campus. He also designed the CARDER regional office. These bamboo structures are representative of emerging efforts to locally enhance the perception of bamboo as a building material. The efficient joinery techniques that incorporate mortar inserted into the poles and steel bolts, are indicative of the sophistication involved in the bamboo design.

3 View looking across the bridge deck at the Universidad Technolόgica de Pereira by Simón Vélez. The bamboo poles are covered with dark coating that protect them from sun and rain.

4 Russell (left) discussing the structural system of the arch bridge with DAGMA architect Daniel (right)

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Interior Corporaciόn Autόnoma Regional de Risaralda(CARDER) where inclined bamboo poles support the roof Exterior of Corporaciόn Autόnoma Regional de Risaralda (CARDER) with structural timber and bamboo poles

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The refreshing tandem: the works of the engineer Laurent Ney perceived by the visual artist Toshio Shibata

What happens when an artist photographs the works of a master designer and builder? The recently published book Toshio SHIBATA / Laurent NEY shows how the photographer Shibata sees the work of Ney, not for its engineering logic but for its inherent poetry. In this book Ney generously shares with us his views on bridge design alongside the visual artistic perspective of  Shibata.  A most unexpected and refreshing tandem.  We are grateful for this blog text which is the introduction to  the book, published with author’s permission. The book  further showcases hundred photographs of the work by Laurent Ney taken by the Japanese artist Toshio Shibata and can be purchased through this link.

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From Toshio SHIBATA / Laurent NEY – (August 19, 2016). Publisher: MER. Paper Kunsthalle.

Introduction

The design of a bridge starts with the context, a context that includes more than just the physical context of the site, its natural surroundings and landscape. A context in its broadest sense takes in historical, technological, industrial, economic, ecological and procedural considerations, all of which are subject to material and procedural constraints, which the project’s author must respect or, better still, transcend.

The work itself, the creative act, is the projection of the imagined object into the future context of the site. The insertion of this object will of course change the context of the site, as the object becomes part of the place, it becomes a place in itself, it becomes context.  The context or the landscape finds itself altered by this insertion, its reading is modified. One can ask oneself if this reading has been improved or not by it, but of course there is no definitive answer to this question, it is eminently subjective. This is where an outsider’s view, such as that of artist-photographer Toshio Shibata, can reveal a denser reality that can be read on various levels.

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De Lichtenlijn Footbridge, Knokke, BE ©Toshio Shibata for Laurent Ney, Design©Laurent Ney

There are a number of different things that I hold to be especially important in the design of a bridge:

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What is the Optimal Shape for a (trussed) Arch?

Arch bridges date back to Antiquity. Steel trussed walkable arch (such as the one shown in the picture above) can be attractive because they can be prefabricated and thus speed up construction time on site. The deck can be cambered to either allow vertical clearance below and compensate for deflection under its own weight. However the maximum slope of the walkable arch is set by accessibility slope guidelines and needs to be shallow. Because of this shallowness, the arch is prone to in-plane snap-through buckling. This means that the arch can assume an inverted equilibrium position. Since the bridge is also lightweight, it natural vibration can coincide with the pedestrian-induced vibration as was experienced by the visitors to the Millenium Bridge on the day of its opening. When that happens, resonance occurs which can lead to severe structural damage.

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Illustration of arch snap-through buckling (Left) and resonance (right)

So what happens when we try to optimize the buckling or dynamic behavior of the walkable trussed arch bridge by allowing the nodes of the truss top chord to displace? The resulting truss forms, optimized in 2D (nodes only allowed to move in x,y plane) and 3D (nodes allowed to move in all 3 directions) are given in the table below.

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Mass Imperfections.

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The curved shapes of hand-made figurines are widespread in the Bethlehem’s tourism industry. What is intriguing about all these crafts is the precision of the forms given the basic tools used for their fabrication. An established hierarchy and apprentice curriculum maintains the artisans’ skills to a certain standard. Becoming an olive-wood master carver is, among other skills, being able to reproduce a complex-geometry shaped figurine while only looking at it.

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Olive wood artisan – Credits: AAU ANASTAS

The process of fabrication of olive-wood objects in Bethlehem calls high-tech mass customization into question. Mass imperfections is a project that experiments the potential of artisanal fabrication for the construction of large-scale structures.

The project experiments the ability of craftsmanship of stepping back into the forefront of the fabrication processes. Mass imperfections challenges high tech fabrication processes by monitoring and anticipating imperfections of highly skilled artisans.

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Revisiting a senior thesis: smart structures

Imagine having a lazy Sunday and laying out in the sun, but never having to get up and move your shade umbrella to a more optimal place throughout the day. This kind of technology is possible when structures and technology combine to make “smart” structures. Your umbrella could be a structure that senses the location of the sun through the solar panels on its covering, and depending on the amount of sunlight available, create optimal umbrella structure shapes for you.

How can this be done?

“Smart structures” are in fact highly possible. For my senior thesis at Princeton, I studied these adaptive sun shading structures, and my built model was composed of a pre-stretched dielectric elastomer adhered to an inextensible compliant frame. At a small scale, these built flexible models could furl and unfurl predictably. However, these built models were very small and labor intensive. What if there was a way to numerically compute possible “smart” structure shapes to more quickly iterate through different designs? In addition to verifying the built flexible models, I strove to understand if a computational method called dynamic relaxation could be employed for the analysis of dielectric elastomer minimum energy structures (DEMES).

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Photos of the DEMES structure studied

So can dynamic relaxation be employed for the analysis of DEMES?

The short answer is yes, it seems like it can.

Dynamic relaxation, a common structural form finding method, was chosen as a numerical simulation technique to simulate the curling action the DEMES. Dynamic Relaxation introduces a fictitious inertia and damping terms into the equations of motion, formulating a static system as the equilibrium state for a group of damped vibrations.

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DEMES equilibrium shape obtained with the dynamic relaxation model

Comparing computed shapes to the physically modeled stretched elastomer structures, there was a noted correlation between equilibrium angle and applied voltage for a biaxial stretch when using a modified Dynamic Relaxation algorithm with bending and clustered elements. Overall, while I found that a numerically modified structure is influenced by material uncertainties approximated input values, the Dynamic Relaxation technique was found capable of predicting the shapes and elastic energy of DEMES.

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