Radical Sources of Design Engineering

24 Werner Sobek RADICAL SOURCES OF DESIGN ENGINEERING Helmut Jahn and Werner Sobek, Post Tower, Bonn, 2003 The Post Tower has a height of 162 metres (531.4 feet) and is marked by its highly dematerialised building envelope. The German architect and structural engineer, Werner Sobek is internationally renowned for his expertise in lightweight structures – an approach that is epitomised by the dramatic elegance of his glazed House R128. Here, Sobek explains how his practice has extended a highly specialised focus on ultra-lightweight facades to that of building structures, facade planning, and sustainable and low-energy solutions, interweaving research and innovation with design and consultancy work. 25 26 Werner Sobek, House R128, Stuttgart, Germany, 2000 opposite: R128 is a fully glazed fourstorey building which is completely recyclable. Moreover, it produces no emissions and is self-sufficient in terms of its energy requirements. It is thus the first example of the Triple Zero principle developed by Werner Sobek. below: R128 is the first building in which diametrical views and outlooks through the building are possible across four storeys. The development that has taken place in the Werner Sobek office over the last  years mirrors the changes that have taken place in the practice’s understanding of planning and design. Where services were initially offered as highly specialised designers and structural design engineers in the field of ultralightweight facades, this soon extended to the ‘in toto’ design of building structures, and within just a few years to include facade planning. It was vital to overcome the interface between the load-bearing structure and the facade, which taken together make up approximately  to  per cent of a building. The next logical step was to extend the firm’s expertise in the fields of energy saving and recycling-friendly design, and to aim to improve the emission characteristics of buildings with the founding of subsidiary company WS Green Technologies. Interwoven with this evolution of design engineering praxis has been the related orientation to research and experimentation carried out through the medium of an academic chair and the leadership of the Institute for Lightweight Structures and Conceptual Design (ILEK) at the University of Stuttgart. It is this duality of involvement that has enabled the firm to continuously refine and redefine the radical principles of design engineering. Transparency The design of housing is continually used by the practice to further develop its architectural concepts and underpin these with engineering advances. House R in Stuttgart () is just such an experiment.1 It is an attempt to comprehend the archi-/structural nature of three-dimensional transparency. The significance of R is to be found in the fact that transparency has here for the first time been achieved and experimented with in the third dimension, beyond the prismatic precedents of Mies van der Rohe and Philip Johnson. It is the first building in which interpenetrating sight lines are possible across four storeys. 27 27 Christoph Ingenhoven and Werner Sobek, European Investment Bank, Luxembourg, 2007 below: The entire 11 storeys are covered by a glass envelope so that large atriums are created between the seven wings making up the basic structure. Unlike the large vertical cable-stayed front facade, the completely glazed roof structure is continuously curved at the northwest side of the building. Christoph Ingenhoven and Werner Sobek, Lufthansa Aviation Center, Frankfurt, 2005 opposite top: The 10 fingers of the building are roofed by double-curved reinforced concrete shells. The atriums lying between the fingers are roofed by double-curved glazed steel-grid shells. The cable-stayed facades of the atriums are up to 25 metres (82 feet) high and can be deflected by up to 400 millimetres (15.7 inches) under wind load. In order to experiment with three-dimensional transparency and to experience its experiential and psychological attributes, the house was built as a personal lived-in experiment. Such a level of transparency can also be built on a large scale.2 The architect Christoph Ingenhoven has proven this time and again with his work: particularly significant examples of this are the European Investment Bank in Luxembourg () and the Lufthansa Aviation Center in Frankfurt (). The Lufthansa building is located in a very difficult urban environment between the airport, railway, dual carriageway and motorway. Despite this, all of the offices are open, flooded with daylight, naturally ventilated and offer wonderful views of the green inner courtyards. In this case the ideal of transparency is not restricted to the building envelope, but is continued throughout the inside of the building providing open, communicative structures that encourage interaction. These attributes also apply to the Post Tower in Bonn designed by Helmut Jahn (). The offices in this high-rise building are open to views of the surrounding area; it is possible to open windows on every level to allow fresh air into the rooms. These are examples of the experiential and environmental attributes of transparency.3 28 Helmut Jahn and Werner Sobek, Post Tower, Bonn, 2003 opposite bottom: The tower is enveloped by means of a second-skin facade. This allows windows to be opened even on the upper levels, and forms an integral part of the energy concept of the building, which is based on minimal energy inputs. A fundamental research question is: How does transparency relate to other design engineering principles that ultimately contribute to ecological design? Werner Sobek seeks to build structures that do not consume fossil fuels, do not generate any emissions and are completely recyclable. All of these things should belong to the fundamentals of designing; a point that also applies in particular to higher education at our universities, just as much as questions of structural stability, facade technologies and so on. Lightweight Lightweight constructions are a precondition for transparency. Lightweight construction means the dematerialisation of objects, to optimise weight to the limit of the possible, reducing integrated grey energy.4 The search for lightweight constructions is the search for boundaries. Designing the lightest possible constructions can be equated with feeling one’s way towards the limits of what is physically and technically possible. It is about the aesthetics and physics of the minimal, and it is about stepping across the dividing lines between scientific disciplines. As far as constructions that bridge long span widths, reach great 29 heights or move are concerned, reduction of self-weight load is an economic necessity and is also often the precondition for physical implementation. Irrespective of scale, lightweight design means savings on the mass of material deployed, and for the most part, also with regard to the amount of energy used. It is here that the ecological aspect begins: building light becomes a theoretical and ethical position. A resolute approach to lightweight constructions requires modifications to the traditional structures of the design process. Establishing system geometries, forming and proportioning load-bearing structures as well as the selection of materials must primarily adhere to the requirement to save weight with other requirements taking on secondary importance; for example, those resulting from architectural considerations or from manufacturing techniques. Moreover, it is not possible to create a design of structural systems of minimal weight on the basis of a simple addition of the geometrically determined building components such as supports, balconies, arches, slabs, shear walls and so on. It is much more the case that the architect or engineer creating a lightweight construction designs spatial force paths, in other words, purely statically conditioned structures, for which he or she subsequently selects suitable materials. 30 Thus the logic of lightweight building is a radical, or fundamental, principle for ecological design.5 One example of researching the boundaries of extreme lightweight construction is the glass dome developed for the ILEK building (). The .-metre (.-foot) diameter dome consists of glued panes of glass of just -millimetre (.-inch) thickness. In other words, the ratio of thickness to the span is :. Other examples include the canopy developed for the pope’s visit to Munich () and the building envelope for Station Z in Sachsenhausen (), the latter having been created by the Stuttgart architect HG Merz. The membrane facade planned by Werner Sobek for Station Z is stabilised by a vacuum – an example of creative building with energy. Geometry In discussing new structures, the question posed is: What is ‘new’? Developing force conditions has nothing to do with lining up basic, geometrically determined building blocks. The task is much more about developing structures that are nothing other than the materialisation of three-dimensional, perfectly designed systems of forces. This is the only possible way to obtain structures that have a high level of structural logic and make very Werner Sobek, Papal Baldachin, Munich, 2006 opposite: On the occasion of his first official visit to Germany, in September 2006, Pope Benedict XVI celebrated a Mass in front of more than 250,000 pilgrims near the New Munich Trade Fair Center. The altar was roofed by a filigree membrane structure to protect him against possible rainfall. Dr Lucio Blandini, Glass Cupola, Institute for Lightweight Structures and Conceptual Design (ILEK), Stuttgart, 2005 above: This prototype of a frameless structural glass shell was designed to demonstrate the structural efficiency as well as the aesthetic quality to be achieved by combining glass as the structural material with adhesives as the joining system. The shell spans 8.5 metres (27.8 feet) and is assembled by gluing only 10-millimetre (0.39-inch) thick spherical glass panes at the edges. HG Merz and Werner Sobek, Station Z, Sachsenhausen, Germany, 2005 below: To protect the remains of the crematorium of the Sachsenhausen concentration camp, a protective shelter was erected in the form of a translucent envelope structure with a homogeneous surface. The roof was designed and built as a membrane structure stabilised by a partial vacuum. Irrespective of scale, lightweight design means savings on the mass of material deployed, and for the most part, also with regard to the amount of energy used. 31 Ben van Berkel (UNStudio) and Werner Sobek, Mercedes-Benz Museum, Stuttgart, 2006 The Mercedes-Benz Museum is not only a tribute to one of the leading car manufacturers in the world, but also a unique demonstration of what structural engineering may achieve today. There are virtually no right angles or plane surfaces in the whole building, which was planned completely in 3-D. 32 efficient use of materials. Consequently, they radiate a very special form of inherent beauty.6 Designing engineering is about the design of the threedimensional flow of forces whose design space is dictated by architectural, climatic or other conditions. It is only after these force conditions have been optimised as much as possible that the designer turns to materialising the force fields with the material most suited to the task. For two-dimensional designs this is purely a finger exercise, but a huge amount of effort and creativity is required when such design is undertaken for threedimensional structural integration. New structures frequently involve innovative geometries. In this context, however, it is not simply a matter of optimising the building from an architectural point of view, but also from the standpoints of creating energetic structural planning and production techniques. If this is not accomplished, the resulting buildings tend rather to represent aesthetically motivated endeavours potentially limited in their habitability or usability. Working with double-curved structures, or with biomorphic structures or bubble systems, requires a deep understanding of analytical geometry. This alone provides the basis from which it is possible to make assessments regarding the feasibility of producing the structures, as well as with regard to special issues of the building process. The Mercedes-Benz Museum in Stuttgart () is an example of the structural and materialisation conditions of complex geometrical structures.7 The double-curved, exposed concrete surfaces were created using a large number of formwork panels, each with a different border, produced utilising a water-jet cutting process to a tolerance of less than  millimetre (. inches). The formwork panels were curved on site and provided a faceted surface. Sustainability If aspects of sustainability and recycling are integrated with complex geometries and dematerialised structures, the necessity for new tools and methods becomes imperative. Building must make huge changes in the face of rapidly accelerating urbanisation, the induced consumption of energy and the resulting emissions. We have simply neglected to develop the appropriate answers to these problems through research and to develop the tools and methods with which to create the solutions. Today, very few succeed in building structures that fulfil the simple demands required to achieve a Triple Zero rating (zero energy consumption, zero emissions (not just CO2) and zero waste creation). First examples such as R, and House D which is currently being planned, are experimentally pushing the production of tools in the realisation of ecological values. It is now necessary to take a holistic view of building and design processes, considering the entire life cycle and beyond. If the components of a building are analysed, it can quickly be concluded that the load-bearing structure has a life cycle of  The imperatives of sustainability will lead to fundamental change in the traditional relationships between architects and structural design engineers, and other engineering and management consultants. years and more; while in facade technology a generation cycle is significantly less than  years, and in technical building services the generation cycles are even shorter. Consequently, buildings should be designed in a manner that allows the individual components to be removed and replaced more easily as their various service life-cycles dictate. The imperatives of sustainability will lead to fundamental change in the traditional relationships between architects and structural design engineers, and other engineering and management consultants. Putting sustainability into practice requires that each individual design engineer takes into consideration complex interrelating issues such as maintenance, repair and recycling. It requires the complete integration of aspects such as energy saving, emissions reduction and more. This cannot be achieved with the sequential planning processes as currently practised. We need to institutionalise new approaches to integral, cross-disciplinary design processes.8 This might enable those of us in new integrated teams of the design engineering professions to undertake a comprehensive examination of all relevant aspects of significance for a building and its users across its entire life cycle. It would then be possible to dedicate ourselves to the most important challenges for this century’s architects and engineers: to make ecology breathtakingly attractive and exciting. 1 Notes 1. Werner Blaser and Frank Heinlein, R128 by Werner Sobek, Birkhäuser (Basel), 2001. 2. Frank Heinlein and Maren Sostmann, Werner Sobek: Light Works, AVEdition (Ludwisburg), 2008. 3. Werner Sobek, ‘Engineered glass’, in Michael Bell and Jeannie Kim (eds), Engineered Transparency: The Technical, Visual, and Spatial Effects of Glass, Princeton Architectural Press (New York), 2009, pp 169–82. 4. Werner Sobek and P Teuffel, ‘Adaptive lightweight structures’, in JB Obrebski (ed), Proceedings of the International IASS Symposium on ‘Lightweight Structures in Civil Engineering’, Warsaw, 24–28 June 2002, pp 203–10. 5. Werner Sobek, Klaus Sedlbauer and Heide Schuster, ‘Sustainable building’, in Hans-Jörg Bullinger (ed), Technology Guide. Principles – Applications – Trends, Springer (Heidelberg), 2009, pp 432–35. 6. Adolph Stiller (ed), Skizzen für die Zukunft. Werner Sobek – Architektur und Konstruktion im Dialog. Müry Salzmann (Vienna), 2009. 7. Susanne Anna, (ed), Archi-Neering: Helmut Jahn and Werner Sobek, Hatje Cantz (Ostfildern), 1999. 8. Conway Lloyd Morgan, Show Me the Future: Engineering and Design by Werner Sobek, AVEdition (Ludwigsburg), 2004. Text © 2010 John Wiley & Sons Ltd. Images: pp 24, 29(t) © HG Esch; pp 26-7, 32 © Roland Halbe; pp 28, 29(b) © Andreas Keller; pp 30, 31(b) © Zooey Braun photography; p 31(t) © ILEK 33