Architecture

I

Introduction

Architecture, the art or science of designing and constructing buildings with durable materials following certain canons, so as to produce structures that are suited to their purpose, and that are visually stimulating and aesthetically pleasing. The English poet Sir Henry Wooton, quoting the Roman architect Vitruvius, stated that “Well building hath three conditions: Commoditie, Firmenes and Delight”.

Historically, architecture has followed a succession of recognizable styles that may, for example, be identified as Gothic, Baroque, or Neo-Classical; or it has a homogenous style associated with a particular culture, such as Greek, Roman, or Egyptian.

Architectural style, be it in a country house, factory, hotel, airport, or religious building, reflects the values as well as the needs of the society that produces it. However, it is governed not only by taste and aesthetic convention but also by a range of interrelated practical considerations; these are principally technology and available materials, an awareness of loads and stresses that certain parts of the building must bear, and the precept that the structure must fulfil the purpose for which it was built.

Vernacular architecture, not treated in this article, is distinct in that it follows no recognizable style, is usually the work of artisans with no formal training in architecture, and is usually made of materials available locally.

II

Building Materials

The availability of suitable materials is intimately linked to the development of skills needed to exploit them and influenced the shapes of buildings. Carpentry developed in areas of the world that were thickly forested. Although it has become scarcer, timber remains an important building material.

In other areas, stone and marble were chosen for important monuments because they are fireproof and durable. Stone is also a sculptural material; stone architecture was often integral with stone sculpture. The use of stone has declined today because a number of other materials, such as glass, steel, and prestressed concrete are more economical to use and assemble.

In regions where both timber and stone were scarce, earth itself was used as a building material. Mud or clay was compacted into walls or made into bricks that were dried in the sun. Later, bricks were baked in kilns, which gave them greater durability.

Thus, early cultures used substances occurring in their environment and invented the tools, skills, and technologies to exploit a variety of materials. The legacy they created continues to inform more industrialized methods.

Building with stones or bricks is called masonry. The elements cohere through sheer gravity or the use of mortar, first composed of lime and sand. The Romans found a natural cement that, combined with inert substances, produced concrete. They usually faced this with materials that would give a better finish. In the early 19th century a truly waterproof cement, the key ingredient of modern concrete, was developed.

Another 19th-century development was the production of steel on an industrial scale; rolling mills turned out shapes that could form structural frames stronger than the traditional wooden frames. Moreover, steel rods could be positioned in wet concrete, which greatly improved the versatility of that material, giving impetus early in the 20th century to new forms facilitated by reinforced concrete construction. The subsequent availability of aluminium and its anodized coatings provided cladding (surfacing) material that was lightweight and virtually maintenance-free. Glass was known in prehistory and, in the form of stained glass windows, is celebrated for its contributions to Gothic architecture. Its quality and availability have been enormously enhanced by industrial processing, which has revolutionized the exploitation of natural light and the transparent properties of glass.

III

Construction

When masonry materials are stacked vertically, as in a wall, they are very stable since every part is undergoing even compression. A more problematic aspect of construction, however, is presented by the need to span the space between walls so as to provide a building with a roof. The two basic solutions to spanning are post-and-lintel construction and arch and vault construction, and its offshoot the dome. In post-and-lintel construction, lintels, or beams, are laid horizontally across the tops of posts, or columns; additional horizontal elements span from beam to beam, forming decks that can support a roof or function as the floor of an upper storey. In arch, vault, and dome construction, the spanning element is curved rather than straight. In the flat plane of a wall, arches may be used in rows, supported by piers or columns to form an arcade; for roofs or ceilings, a sequence of arches, one behind the other, may be used to form a half-cylinder (or barrel) vault; to span large symmetrical spaces, an arch may be rotated from its peak to form a hemispherical dome.

Post-and-lintel construction can be executed in various materials, but gravity subjects the horizontal members to bending stress, in which parts of the member are under compression while others are under tensile stress. Wood, steel, and reinforced concrete are efficient as beams, whereas masonry, because it lacks tensile properties, requires much greater bulk and weight to be effective. Vaulting permits spanning without subjecting material to tension; it thus enables large areas to be roofed with masonry or concrete. The outward thrust of vaulting, however, must be counteracted by abutment, or buttressing.

Trussing, timbers forming a frame, is an important structural device used to achieve spans with less weighty materials. Spanning systems can be made of any appropriate material—most often wood, rolled steel, or tubing—and, by subdivision into triangles, can take almost any shape. Thus a frame composed of three end-connected members can be extended indefinitely by the principle of triangulation—attaching a horizontal tie beam to the bottom of two peaked rafters. Each separate part is then subject only to either compressive or tensile stress. In the 18th century, mathematicians learned to apply their science to the behaviour of structures, thus making it possible to determine the degree of stress in a given situation. This led to the development of space frames, which are simply trusses or other elements deployed three-dimensionally.

Advances in the science of analysing structural behaviour resulted from the demand in the 19th century for great civil engineering structures: dams, bridges, and tunnels. It is now possible to enclose space with suspension structures—the obverse of vaulting, in that materials are in tension—or pneumatic structures, the skins of which are held in place by air pressure. Sophisticated analysis is particularly necessary in the case of very tall structures, because stresses that could be exerted by the effect of wind or earthquakes then become a more important consideration than the effects of gravity.

Architecture must also take into account the internal functional equipment of modern buildings. In recent decades, elaborate escalator and lift systems, the control of temperature and humidity, air conditioning, artificial lighting, sanitation, fire precautions, and the distribution of electricity and other services have been developed. This has added to the cost of construction and has increased expectations of comfort and convenience.

Certain broad principles have always been discernible in the purposes for which buildings are constructed. The noblest works of architecture—temples, churches, mosques—celebrate the mysteries of religion and provide assembly places where gods can be propitiated or where the faithful can receive religious instruction and participate in symbolic rituals. Another important purpose has been to provide physical security: many of the world’s most permanent structures were built for reasons of defence.

Related to defence is the desire to create buildings that reflect civic pride or serve as status symbols. Palaces for kings and emperors unmistakably proclaimed their power and wealth. People of privilege have always been prominent patrons of designers, artists, and artisans, and their projects often represent the best work of a given period. Today large corporations, governments, and universities play the role of patron in a less personal way.

The proliferation of types of building today reflects the complexity of modern life. Modern Western architecture is overwhelmingly concerned with the creation of mass housing, large office buildings, shopping centres, and supermarkets, schools and universities, hospitals and clinics, and airports, hotels, and holiday resorts. Individual buildings are not seen in isolation, however. The attention of architects and their clients is increasingly focused on the interaction between new and existing buildings, and town planning takes into account the impact that new buildings have on particular urban neighbourhoods.

IV

The Ancient World

The architecture of the ancient world, of the Orient, and of the pre-Columbian Americas may be divided into two groups: indigenous architecture, or ways of building that appear to have developed independently in distinct, local cultures; and Western-style architecture, which ultimately traces its roots back to the systems and building methods of Greece and Rome. The oldest examples of architecture solid enough to have survived, if only in the form of vestigial traces, date from the development of the first cities.