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Home > Journal > Issue Ten > The art of building is indivisible! The art of building is indivisible! - Maurizio Scalera For the first time they allowed a renaissance of cast-steel in modern structural engineering. Utilized for example in the roof of Munich Olympics Arenas (1972) where the numerous saddles and joints with ever changing geometry could never have been realized without a new type of styro-foam forms for cast steel, or in the joints of the tubes and their connections with the concrete deck and the piers in the Humboldthafen Railroad bridge. The development of the new material Glass Fibres Reinforced Concrete (GRC) is also very interesting in which alkali-resistant glass-fibres are gunnited or mixed with the mortar resulting in a concrete that, in addition to its compressive strength, has a permanent tensile strength, and therefore appears to be ideal for shells like the one in the Garden Exhibition in Stuttgart (1977). Another new material used widely by SBP, especially in wide-span roofs of sport facilities or stadia, is the PTFE-coated glass-fibre membrane which offers several advantages against other materials: its limitless variety of shapes, its lightness also for large spans, quick and easy to assemble, dismantle and recycle, and the possibility of being a translucent fabric. On the other hand the costs are high and it doesn't last more than twenty-thirty years. With the PTFE they realized the roofs, among other projects, of Seville Olympic Stadium (1999), NSC Competition Pool and Outdoor Stadium in Kuala Lumpur (1997), Pusan Dome (2001) and the Frankfurt Stadium under construction (expected completion 2005). During the lecture he explained some principles behind his structural engineering applications by showing some apparently simple every day life examples. An ordinary wire kitchen sieve in reality is a sophisticated double-curved surface, made from plane square wire mesh and receiving its dome shape merely by changing the mesh angles. This geometric trick, combined with a stiffening cable-net structure, permits one to obtain the ideal shell, whether made in concrete, glass-grid or textile membrane, which is very light and efficient from a structural point of view (Museum Courtyard roof, Hamburg). Even the spoked wheel is a highly intelligent structure. The rim, soft by itself, becomes surprisingly stiff with the addition of thin pre-stressed spokes. Therefore this stratagem can be applied to a larger scale becoming a transparent diaphragm for the stiffening of tubes (cable net cooling towers and solar chimneys) or of cylindrical light-weight glass or membrane roof which absorbs the transversal loads acting from the rim to the hub (glass roof for DG-Bank, Berlin).
Also extremely important is the research made by SBP and the University of Stuttgart in the field of natural power, which has led to the application and production of new devices for the harnessing of solar power. The dish-Stirling system consists of a large parabolic mirror that concentrates the solar radiations onto a small heating surface with little tubes where a gas is heated to a temperature of almost 700�C which drives a Stirling engine generating electrical power. The new special features of this system are not the scientific principles, but the construction methods that make very large and accurate concentrators possible by the development of the stretched metal membrane technology with a thickness of just 0.5mm.
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