STRUCTURAL DESIGN FOR ARCHITECTURE

Structure and architecture

Fig. 1.20 Forth Railway Bridge,

Scotland, 1882-90, Henry Fowler

and Benjamin Baker, engineers.

Two types of structure are visible

here. Short-span viaducts,

consisting of parallel-chord

triangulated girders, are used at

each end where the ground

conditions allow closely-spaced

foundations to be provided. The

two deep river channels

separated by the island are

spanned by an arrangement of

three pairs of balanced

cantilevers. The configuration of

the bridge was determined by a

combination of site conditions,

structural requirements and

function. [Photo: P. & A.

Macdonald]

keep beam spans short. Very large single-

storey structures have, however, been

constructed (see Section 6.2).

1.5 Structural design

As with any other type of design, the evolution
of the form of a structure is a creative act
which involves the making of a whole network
of interrelated decisions. It may be thought of

as consisting of two broad categories of activ-

ity: first, the invention of the overall form and

general arrangement of the structure and,

secondly, the detailed specification of the

precise geometry and dimensions of all of the

individual components of the structure and of

the junctions between them.

In the case of an architectural structure both

of these activities, but especially the first, are

closely related to the broader set of decisions

connected with the design of the building. The 17