Max Bögl, Studium an der TU München und ETH Lausanne, seit 1997 Architekturbüro mit Andreas Gierer, Gesellschafter und Aufsichtsratsvorsitzender der Max Bögl Bauunternehmung. Andreas Gierer, seit 1997 Architekturbüro mit Max Bögl, seit 2005 Lehrauftrag für Methodik der Darstellung und Gestaltung an der Akademie der Bildenden Künste München, seit 2010 Professur für Entwerfen, Darstellen und Gestalten an der FH Kaiserslautern.
16 Pollerleuchte aus faserbewehrtem Sichtbeton, in einem Vorgang mit dem Kopf nach unten gegossen; Architekten: Bögl Gierer in Zusammenarbeit mit Lichtplaner Markus Widmann 17 Maschinenbauteil aus Beton mit polierter Oberfläche 18 Maschinenbauteil aus Beton mit gefräster Oberfläche 16 Polished luminaire bollard in fibre-reinforced exposed concrete; cast in a single process with the head downwards; architects: Bögl Gierer in collaboration with lighting planner Markus Widmann 17 Concrete machine component with polished surface 18 Concrete machine component with milled surface
Max Bögl studied at the Technical University in Munich and the ETH Lausanne. Since 1997, architectural practice with Andreas Gierer; partner and chairman of board of Max Bögl construction company. Andreas Gierer: since 1997, architectural practice with Max Bögl; since 2005, lectureship in the methodology of representation and design at the Academy of Fine Arts, Munich; since 2010, professor for design, visual representation and planning at the University of Applied Sciences, Kaiserslautern. 16
ally prestressed. With an additional in-situ reinforced concrete layer, they can span distances of up to 27 m. Openings are generally formed at works. • Prestressed hollow-core slabs are capable of bearing full loads immediately after assembly. No additional support is necessary during erection. The individual elements are rigidly connected by grouting the reinforced joints. Depending on the live loading, a floor slab 40 cm deep can span distances of 13 –15 m without intermediate support. Down to the 1990s, prefabricated forms of construction could be justified only where a large number of identical elements occurred. Special units immediately reduced the economic viability of a scheme. In view of the largely automated process of prefabrication today, the situation has changed markedly. Although individual elements still reduce the economic practicability, variations can now be computer controlled. Above all, geometries that are curved in two dimensions are subject to CNC and can be formed with the greatest precision. One approach is to prefabricate standard rough castings that can be individualised through further processing. Conditions in fabrication workshops today allow a high degree of precision in the production of precast reinforced concrete elements, which makes itself apparent in aspects such as the incorporation of anchors, electrical installations, thermal activation, etc.
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Assembling precast units on site and installing any supports for this purpose calls for threaded couplings or similar components. Their position should be determined in such a way that they will not be subsequently visible. Alternatively, they can be used as a design feature. With prefabricated elements, greater scope exists for surface design than with in-situ concrete. Additives and pigments can be employed to modify the appearance, or moulds can be laid in the formwork to create relief patterns. Steel shuttering and computercontrolled compaction of the concrete result in a very smooth surface (Figs. 5, 10). Subsequent grinding can bring out the aggregate, and colouration can lend the concrete a stone-like character. The quality of the jointing pattern plays an important role in the overall impression created by a facade. The treatment of the edges of slabs is, therefore, of special importance. Standard details can be formed by inserting a 45° triangular strip in the shuttering, by using sealing strips, or by constructing silicone joints with a radius of 3 mm (Figs. 5, 10). The width of joints will depend on the length of the constructional element and other factors; e.g. the greater thermal loading to which south-west facades are subject. Care must be taken with the edges of concrete units, since they can easily be damaged during transport and assembly. Although they can be repaired, this will usually remain evident afterwards. The
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joints of curtain walls can be left open, whereas in the case of sandwich elements, the joints must be flexibly sealed (Figs. 9 –11), otherwise moisture will enter the construction. By finishing the sealant below the surface level, shadow joints can be formed. In recent years, the cement and concrete industry has developed many new materials. These include high-density, self-compacting concretes, and fibre and textile reinforcement. Concrete with a density of 100 – 200 N/mm2 and a specific gravity of roughly 2.6 kg/dm3 are referred to as “high-density” types. With these, the cross sections of components can be reduced considerably. Using high-density concrete with textile reinforcement, a 12 cm conventionally reinforced facade slab could be manufactured to a thickness of 3 cm, since the covering layer can be considerably thinner. The textile and carbon industries have only just begun to explore here. In addition, subsequent thermal treatment of concrete reduces any changes of form to a minimum. Methods of working finished elements are advancing, too. Concrete can now be worked to a hundredth of a millimetre precision (Figs. 13, 17, 18). The same applies to shuttering. Concrete is becoming a rival material to steel in certain areas (Fig. 17). In mechanical engineering, for example, its property for damping vibration and its inertia when subject to temperature changes are of great advantage. Using fibre reinforcement, finely shaped concrete furnishings and other objects can be manufactured. For instance, a double washbasin, weighing roughly 200 kg, has been developed for commercial uses; and a bollard luminaire (Fig. 16), containing a large metal box with LED and electrical installations, has been cast in a single working process. Manufacturing precast concrete components has thus become a high-tech activity (Figs. 13, 17, 18), and it is worthwhile for architects to consider the subject of prefabrication more closely, since technology and automation will continue to gain ground. Similarly, wood and concrete hybrid forms of construction – already found in many realms, such as housing construction today – are yet another topic for the future.
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