Hybrid Forms of Construction in Structural Planning

Author: Volker Schmid

Hybrid materials and forms of construction are key technologies today. The upper part of the fuselage of an Airbus A380 consists of glass-fibre-reinforced aluminium (GLARE), for example. This laminated composite material is made up of a series of thin layers of aluminium and glass-fibre-reinforced synthetic. The advantages of the respective materials improve the impact- and flame-resistant behaviour of the fuselage. Above all, though, the GRP that is incorporated reduces the speed with which cracks spread. New composite substances and the incorporation of traditional materials help to extend the technical and design scope of engineers and architects. In the Metropol Parasol project in Seville, steel, concrete, multi-veneered ­layers of wood, and polyurethane thick-film coatings were combined and assembled to form a new kind of hybrid overall structure. Hybrid forms of construction have been used for centuries in building, of course. In 1811, the architect François-Joseph Bélanger and the engineer François Brunet erected the iron lattice-shell dome over the courtyard of the Bourse de Commerce in Paris. Initially, it was covered with iron sheeting. In 1838, this was replaced with glass. Today, calculations show that the stability of the dome was achieved only through the effect of the glass. In 1826, the engineer Henri Navier wrote that once the nature of the forces is known that have an effect on the construction, one can choose the most advantageous material for each part. “Hybrid”, “composite” and “mixed” forms of construction are not precisely defined and are used in this paper to refer to the same thing. As Navier argued, hybrid forms of construction are based on the division of an object into its functional, technical elements. These may be subject to quite different forms of loading and can be efficiently implemented with various materials and structural forms.