Structural Design for Architecture
represent the best compromise between
complexity and simplicity for buildings which,
though not necessarily of small scale, have no
requirement for large interior spaces and
therefore for long spans. At the other extreme- the very long span - highly complex systems
such as steel-cable networks or doubly-curved
reinforced concrete shells were seen to provide
the best structural solutions. For intermediate
spans, intermediate levels of complexity are
appropriate.
A happy consequence of regarding the
achievement of maximum economy of means
as the principal criterion of good structural
design is that it is also the condition which is
likely to result in the lowest-cost structure.
Although monetary cost is, in important ways,
an artificial yardstick, it is in fact related to the
totality of the resources, of all kinds, which
must be committed to a structure.
A factor which affects the precise level of
complexity which is appropriate for a particular
structure is the economic climate in which it
will be built. If, for example, the cost of labour
is low in relation to that of materials, which is
the normal situation in a non-industrialised
economy, a more complex (and therefore more
efficient) structural form is justified than if the
reverse is true. The structure type which is
most appropriate for a particular span in an
industrialised economy, in which labour costs
are high, might therefore be simpler than the
most appropriate type of structure for the
same span in a 'developing' country.
As was noted above, good examples of well-
resolved architecture of the 'structure
accepted' type are found in the early modern
period. This was due to the happy compatibil-
ity of the favoured orthogonal aesthetic with
the post-and-beam structure, which is the
most appropriate structure type for the
relatively short spans which occur in the
majority of buildings.^7
To summarise, the building designer who
wishes to achieve technical as well as aesthetic
and programmatic excellence must select a
type of structure which is truly appropriate for
the span and load conditions involved. This is
likely to have a fairly profound effect on the
overall form of the building and in such a case
the technical and aesthetic agendas must be
made compatible. Because the range of struc-
tural options may be limited, particularly by
the span involved, the approach to the
aesthetics must be flexible. Where this
methodology is adopted the structural solution
will inevitably be an adaptation of one of the
basic forms of structure outlined in the follow-
ing chapters.2.2.4 Structure symbolised
One of the features of buildings designed in
accordance with the 'structure accepted'
approach discussed above is that the structure
itself rarely constitutes a prominent part of the
visual vocabulary and may even be entirely
hidden from view. The objective of the 'struc-
ture accepted' approach is not overly to
express the structure visually but to ensure
that it will be well designed and well
integrated with all other aspects of the build-
ing. Where the relationship between structure
and architecture is of the 'structure symbol-
ised' type, the structure is emphasised visually
and constitutes an essential element of the
architectural vocabulary.
In the 'structure symbolised' approach the
structure is treated as a set of visual motifs
and decisions concerning the size, shape and
arrangement of the structural elements are
influenced as much by visual as by technical
criteria. The technical performance of the
structure is secondary to its aesthetic role and
the technical quality of the structural design is
frequently compromised as a result. This is an
inevitable consequence of this method of
working and must be accepted if it is used.
In recent architecture the 'structure symbol-
ised' approach has been employed almost
exclusively as a means of expressing the idea of
technical progress and has therefore been
associated principally with the Modern7 In the context of architectural structures the
post-and-beam arrangement is non-form-active. For
short spans, this is, in most cases, the best structural
solution. See Macdonald, Structure and Architecture,
30 Chapter 6 for a discussion of this.