Chapter 3
Steel structures
3.1 Introduction
Steel is a material which has excellent struc-
tural properties. It has high strength in tension
and compression and is therefore able to resist
bending and axial loads with equal facility; it is
the strongest of the commonly used structural
materials, being approximately twenty times
stronger than timber and ten times stronger
than concrete. It is therefore used to make the
tallest buildings and the enclosures with the
longest spans. Its most common application,
however, is for building frames of moderate
span, in a wide variety of configurations.
3.2 The architecture of steel - the
factors which affect the decision to
select steel as a structural material
3.2.1 The aesthetics of steel
The visual vocabulary which is associated with
steel structures contains some of the most
powerful images of modern architecture. The
glass-clad framework (Fig. 3.6), the use of
slender, precisely crafted structural com-
ponents as visual elements (Figs 3.1 and 3.9)
and the celebration of structural virtuosity in
the form of either breathtakingly long spans
(Fig. 3.10) or very tall buildings (Fig. 3.11) are
all different aspects of the expressive, and
impressive, possibilities of steel. These
aesthetic devices have been used from the
beginning of the modern period and are still
part of the twentieth-century architectural
palette. They are often the primary reason for
the selection of steel as the structural material
for a building.
Steel became available as a building
material in the second half of the nineteenth
century, following the development of econom-
ical processes for its manufacture, and,
although its expressive possibilities were not
used initially, it was quickly absorbed into the
well-established tradition of metal-frame
building which had arisen in connection with
the use of cast and wrought iron (Fig. 3.2). IronFig. 3.1 Channel 4 Headquarters, London, England,- Richard Rogers & Partners, architects. Concepts such
as neatness, precision and high quality control are readily
conveyed by the use of an exposed steel structure. [Photo:
E. & F. McLachlan] 49