STRUCTURAL DESIGN FOR ARCHITECTURE

Structural Design for Architecture

Fig. 2.4 Sailing Yacht

'Gipsy Moth IV. In the

construction of ships and

yachts timber has been

used to produce a wide

variety of complex shapes.

The material itself places

little restriction on form

but the production of

geometries like that illus-

trated is highly labour

intensive and therefore

expensive. [Photo: The

Maritime Trust]

26

the objects concerned are made from steel. A

similar statement could be made of reinforced

concrete but in this case the exemplars would

perhaps be grain silos or water towers. Timber

too is capable of being used in a very wide

range of shapes although, because timber is

less strong than steel or reinforced concrete,

these are of a smaller scale. Again, ships and

yachts serve as examples of the level of

complexity of form which is possible (Fig. 2.4).

In all of these examples a criterion other than

structure, such as hydrodynamic performance

or adherence to fashion, was the dominating

influence on the form which was chosen.

The structural factor which is common to the

three materials considered above (steel,

reinforced concrete and timber) and which

allows them to be shaped into almost any

form, is that they can all resist tension,

compression and bending.^4 The high strength

They can therefore be used to make any type of struc-

tural element: form-active, semi-form-active or non-

form-active. The same cannot be said of masonry,

which has very limited tensile strength and therefore

also limited bending strength. As is shown in Chapter

5, the need to prevent significant tensile stress from

developing imposes constraints on the structural forms

of masonry.

of steel and reinforced concrete, together with

the fact that very effective structural joints can

be made between components of these mater-

ials, are additional factors which make possi-

ble the creation of practically any form.

It may seem surprising therefore that, in the

period since these materials became widely

available to the builder in the late nineteenth

century, architects have availed themselves so

little of the potential for the free invention of

form which they made possible. Instead, archi-

tects have, for the most part, generally contin-

ued to produce buildings with plane vertical

walls and horizontal or pitched roofs which are

not significantly different in overall shape from

the traditional architectural forms which were

evolved from the much more restrictive struc-

tural technology of masonry. There have been

several reasons for this, most of which were

not technical.

Perhaps the most significant reason for the

apparent lack of basic (as opposed to superfi-

cial) complexity in the architectural forms of

the twentieth century has been cultural. In the

period in which the freedom to experiment

with form has been available it has not gener-

ally been fashionable for buildings to be given

irregular or curvilinear forms. For ideological

reasons, modernity preferred to accept the

vocabulary of orthogonality, which symbolised