STRUCTURAL DESIGN FOR ARCHITECTURE

Fig. 4.2 Hennebique's system for reinforced concrete,

which was patented in 1897, was one of a number which

were developed in the late nineteenth century and which

led to the subsequent widespread use of the material for

multi-storey structures.

with which its properties can be augmented.

The most important of these is steel, in the

form of small-diameter reinforcing bars, and

this produces the composite material

reinforced concrete, which possesses tensile

and flexural strength as well as compressive

strength. Reinforced concrete can therefore be

used to make any type of structural element.

Concrete can be either cast directly into its

final location in a structure, in which case it is

said to be in situ concrete, or used in the form

of elements which are cast at some other

location, usually a factory, and simply assem-

bled on site, in which case it is referred to as

precast concrete. The relative advantages of

the two types are reviewed in Section 4.4. Both

in situ and precast concrete can be produced in

ordinary reinforced form or in pre-stressed

form. The distinctions between these types are

discussed in Section 4.3.2.

4.2.1 The aesthetics of reinforced concrete

The opportunities which reinforced concrete

offers in the matter of architectural form can

be seen by examining the range of building

types for which it has been used during the

relatively short period in which it has been

available as a structural material.

Although a type of concrete was used to

good effect by the architects and engineers of

Roman antiquity the modern material,

reinforced concrete, dates from the nineteenth

century. 'Roman' cement, the forerunner of the

present-day Portland Cement, was patented in

the UK by ). Aspden in 1824, but the earliest

uses of reinforcement in concrete appears to

have occurred more or less simultaneously in

France and USA where, in the 1880s and 1890s,

Francois Hennebique (Fig. 4.2) and Ernest

Ransome, respectively, each developed framing

systems for buildings based on this principle.

Another early innovator was Robert Maillart,

whose development of the two-way-spanning

4.2 The architecture of reinforced

concrete - the factors which affect

the decision to select reinforced

concrete as a structural material

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Structural Design for Architecture