Major Works
To achieve efficiency of material use in thin shell structures, their form must reflect the forces flowing through them. In the German shell design and building tradition, we distinguish two approaches to the challenge of finding that 'right' form: the geometrical and the form-found approach.
Geometric Shape
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Geometry is a tool that has been used since antiquity for the development of architectural forms. These forms are thus limited by the rules imposed by analytical geometry and the designer's imagination. Through the centuries, architecture has developed around "simple" geometries chosen for their constructive or structural qualities. In Germany during the first half of the 20th century, the design of reinforced concrete roof shells was based mainly on these pure geometrical shapes. They were defined by elementary analytical formulas such as spherical or parabolic domes, cylindrical shells, hyperbolic parabolic roofs, etc. One reason of course was that geometrical shapes could be handled by analytical shell analysis developed by Franz Dischinger (1887-1953) and Ulrich Finsterwalder (1897 - 1988) who both worked for the German engineering company Dyckerhoff and Widmann. Dischinger tested his theory in the design of the shells of the Leipzig Grossmarkthalle (Leipzig, 1929), the at the time largest span reinforced concrete dome. In recent years innovative steel and glass lattice shells have been designed by Jörg Schlaich (1934 - present) and Hans Schober (1943 - present) from Schlaich Bergermann and Partners. The barrel and dome lattice shell over the courtyard of the Hamburg History Museum (1989, Hamburg) has announced the era of discrete shells. Surfaces of revolution, translational surfaces, and scale-trans surfaces lend themselves excellently to shell action and discretization into straight elements.
Form-found Shape
Of all traditional design parameters, the global shape mostly decides whether a shell will be stable, safe, and stiff enough. The curved form is of vital importance to achieve stability through membrane stiffness. Shell bending needs to be avoided by finding the "right" geometry, so that under self-weight only membrane action results. Membrane action makes efficient use of material. The important structural design challenge lies in the determination of that three-dimensional form. The Swiss engineer Heinz Isler (1926-2009) and the German architects Michael Balz and Frei Otto (1925 -present) have pioneered and experimented with physical form finding techniques. Isler and Balz inverted hanging membranes, subject to gravity load, to form the final shape of the Grotzingen Outdoor Theater Roof shell (1977, Aichtal). For the Balz house (1980, Stetten), they derived shell forms from a pneumatic process. Otto explored the potential of the inversed hanging network and invented 'bending active' lattice shell systems for the Multipurpose Hall of the Bundesgartenschau (1975, Mannheim).
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Below is a short list of notable German shell designs and how their form was generated. The linked essays were produced by the students in the CEE463 course "A social and multi-dimensional exploration of structures" in Fall 2012.
Structure Name |
Year | Structural Form | Student Authors |
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1980 | Form Found: Pneumatic | Anjali Mehrotra Victoria Richardson Sabrina Siu |
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1977 | Form Found: Hanging | Tessa Maurer Elizabeth O'Grady Ellen Tung |
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1975 | Form Found: Hanging | Jarred Mihalik Melody Tan Sekai Zengeza |
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1975 | Form Found: Hanging | Bennu Boyner Julie Ditchfield Mariam Wahed |
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1929 | Geometric: Dome | Gabriella Figueroa Thomas Mbise Margaret Owensby |
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1989 | Geometric: Barrel | Yerab Ermias Bar Shabtai Peter Szerzo |