Construction is one of the oldest human activities. Since the existence of man there has always been the activity of construction. And we know that construction is one of the components of architecture, the others being aesthetics (or form) and function. It is obvious that materials constitute the fundarnental part,the essence of construction and technology. We can not forget also that technology has always influenced the form of buildings. In every period technical possibilities provided by materials constitute a source of inspiration for architects. The Parthenon and a Gothic cathedral, both, are the products of techniques different in specificy.

Mankind lived for a long period using only the means of nature. Sometimes in caves if he was able to find one, or in open air in huts constructed by himself of tree branches covered by leaves or animal hides. In addition to shelter he also constructed megalithic monuments such as menhirs, dolmens and cromlecks.

Later, he used sucessively cob and clay, stone and wood. On one hand he tried to solve the problem of shelter, on the other he continued to create monuments such as temples and Egyptian pyramids. The massive construction system based on piling up of materials constitutes a characteristic which is common in every archaic architecture.

In every period, architecture had various functions. In ancient Egypt it is an architecture of tombs. The Greek period is for temples. Rome created amphitheatres, thermal baths, bridges and aqueducts.
The Middle Ages gave us a religious and military architecture; the Renaissance, palaces. The 19 th century constructed rental flats (in Europe). And the 20 th century created new functions such as industrial buildings, mass housing, etc.

Greek ternples are great sculptures without functional internal spaces.
The elernents of a Greek temple are an elevated stylobate on which are based a series of columns surmounted by a continuous entablature which supports a roof whose construction is of timber. Therefore the Greek construction system could be summarised by “columns + lintel course”.

Romans covered large spaces by using vaults or domes. The arch was invented by the Assyrians but they seldomly used arches because they did not have enough stone for their construction. The fact that the arch existed in Egyptian arehitecture and the vault in oriental architecture earlier than Rome is of course interesting; but we can not deny that Roman architects knew how to use these arches and vaults to conceive larger spaces and scales (1). The arch was largely used by Romans and they also are credited for being, the first in using it between two columns.

The Romans were using stone and brick as fundamental materials. They were also utilising a sort of cement with which they were preparing a kind of concrete. For example the cupola of Pantheon was constructed with this concrete. By using these materials and these means, Romans constructed large thermal baths, amphitheatres, palaces, bridges and aqueduets. Romans were not perhaps good artists but they were really good engineers.

Gothic architecture with its diagonal ribs and flying-buttresses cancelled the superfluous material of vaults and walls. In Gothic architecture the technique of diagonal ribs countered lateral forces; “flying-buttresses and counterforts became muscular arms capable to channelise forees” (2). We can say that Gothie work struggled against matter. But it does not particularly display a technical progress in the manner of constructing a building. There were always the same materials used and always with the same methods.

“Renaissance art did not display any sensational innovation in the field of construction either. The Florenee Cathedral as well as Saint Peters of Rome are colossal applications of the architectural principles known for a longtime. And here we are speaking about outstanding works which had the mark of a new style. But in contrary country houses began to submit to the influence of styles from the 18 th century” (3).

With the industrial revolution the structure of European society lost its social equilibrium and in this chaotic situation the new middle class, “bourgeoisie”, preferred an ecclecticist architecture. Thus the 19 th century architecture is only an architecture of facade which repeats old forms.

On the other hand the 19 th century was a century of industria1 inventions. Stee1 and concrete which are fundamenta1 materials of the 20 th century are products of the 19 th century.

The new materials and the new technological possibilities, the changing social structure and new needs, new functions of the secondary civilisation (industrial era) were not too late to require and to form a new architecture: Modern Architecture. “What we call Modern Architecture was born in the last ten years of the 19 th century and in the first years of the 20 th century by the conscioussness of certain architects and by the power of engineers and big contractors. Their reaction was violent and they immediately thought that housing had to benefit from technical progress” (4).

It is worth taking a close look at the materials of this new architecture. “Iron, as a formable material was known for almost five thousand years as witnessed by discoveries made in Mesopotamia and in Egypt. Producticon methods were so primitive that iron was produced only in very limited quantities and it was considered a precious metal and its use was not envisaged for construction” (5). Its use was reduced to clasp and fix masonry. It was in the 16 th century that the process of blast – furnace was used for the first time to produce cast iron.

The use of iron started just at the moment that creative inspiration seemed to get poorer. It was natural to wait for a rejuvenation of this material. In 1850 Théophile Gautier said: “A characteristic architecture is created immediately after the use of a new product provided by new industry.

The use of iron permitted and imposed several new forms as can be noticed in railway stations, in suspended bridges and in vaulted roofs of winter gardens:’ These hopes were deceiving at the beginning. The use of a new building material contains in itsef the possibility of a new language of form but in the condition that creative wish intends to make the best of it. It was not the case in the first part of the 19 th century, nor in the following years.

Iron such as we use today exists since the use of Bessemer (1855) and Thomas (1879) processes. In many works of this period iron is used frequently by an addition of decorative design borrowed from the forms of the past: for example the Coalbrookdale Bridge in England. This bridge marks the first important use of iron in a construction. In fact this is a structure in cast iron with a span of approximately 30 m. spanning the Savern river.