Structure and architecture
complicated to construct. Combined-action
structures are therefore used in situations in
which intermediate levels of efficiency are
required, for example in the medium-span
range. They are most often found in the form
of skeleton-frame arrangements.
Fig. 1.13 Olympic Stadium, Munich, Germany, 1968-72.
Behnisch & Partner, architects, with Frei Otto. The struc-
ture of this canopy consists of a network of steel wires (the
very fine square mesh) supported on a system of masts
and cables. The pattern of heavy rectangular lines results
from the flexible joints between the cladding panels.
Highly efficient structure types such as this are required
where long spans are involved. [Photo: A. Macdonald]
1.4 Structural materials
The form and general arrangement of architec-
tural structures are greatly influenced by the
properties of the materials from which they are
constructed. For this reason the basic structure
types appropriate to the four principal materi-
als of steel, reinforced concrete, masonry and
timber are described in separate chapters.
Each material has its own individual charac-
teristics in terms of physical properties and
manufacture which contribute to determining
the structural forms for which it is most
suitable. These issues are considered in detail
in the chapters on individual materials. Only
the most general aspects are reviewed here.
The properties of materials which affect the
load-carrying performance of a structure are
strength, elasticity and, to a lesser extent,
specific gravity (which determines the self-
weight of structural elements). Other signifi-
cant physical properties are durability (i.e. 11
