Steel structures
tension and compression. Its deficiencies -
poor durability, poor performance in fire, the
difficulty of shaping it into useful components,
the high weight of the components - were not
significant, and would be overcome by employ-
ing other technologies. The large ecological
cost, in terms of transportation of raw materi-
als and of the high energy consumption and
pollution associated with its manufacture,
were not an issue at the time. So far as the
modernists were concerned, here was a new
and exciting material whose expressive possi-
bilities, if explored, might lead to a truly
appropriate architectural vocabulary for the
twentieth century.
The technology of the steel framework
contributed to the aesthetics of architecture in
the 1920s and 1930s in two quite separate
ways. Firstly, it was crucial to the development
of the glass-clad building; secondly, it made
tenable the overt use of structural elements as
constituents of a modern visual vocabulary.
These two aspects of the aesthetics of
Modernism were, and still are, often combined
by architects and confused by critics. They are,
however, different and distinct aspects of the
relationship between architecture and the
structural technology of steel frameworks.
The aesthetic programme of the glass-clad
framework is concerned with 'transparency'.
This, and the use of 'crystalline' form, were
given symbolic meaning in the 1920s by the
Expressionists, notably Bruno Taut. One of the
most striking images to be published by this
group, however, was the well-known glass
skyscraper project of Mies van der Rohe (Fig.
3.4). Despite its Expressionist genesis this
building form survived the gradual triumph of
Rationalism - the Rationalists could regard the
glass-clad frame as a logical and honest reduc-
tion of the elements of a tall building to its
bare essentials - and was used at every scale
in the architecture of Modernism, from small
domestic buildings to the corporate sky-
scrapers which dominate the skylines of most
capital cities.
Among the visual sources of this architec-
tural vocabulary of glass and steel were the
iron-framed warehouses, factories and railway
Fig. 3.4 Glass skyscraper project, 1922, model. Mies van
der Rohe, architect. In the early twentieth century many
visionary architects considered mass-produced high
quality glass to be the ultimate modern building material,
principally because it allowed the exterior of a building to
be 'dematerialised'. The almost featureless high-rise struc-
ture faced in glass was an important architectural innov-
ation of the early modern period.
53
