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Building Design/Architecture - Prehistory, Medieval Architecture—romanesque And Gothic, The Renaissance And The Baroque, The Industrial Revolution—new Materials - Classical architecture

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Architects design buildings, but architecture is more than just building design and more than just art on a massive scale. Architecture is about light and space. It is about stimulating emotions in the people who see and inhabit the structure. Architecture creates an environment, whether it is the uplifted spirituality of the Chartres Cathedral, the drama and anticipation of the Schauspielhaus auditorium, or tranquil serenity of Fallingwater. It is experiential. When you approach or enter a building you move through the space, the scale changes, the proportions shift around you. This is what makes architecture glorious; the way it manipulates light.

Structure is fundamental to architecture. For a design to move from the mind of the architect to reality, there must be a method of building it. The development of structural forms has thus been a driving force in architecture, every bit as much as changes in social order and historical events. Through history there have been relatively quiet periods of stylistic development, interspersed with almost muscular leaps of structural innovation such as the Roman period, the Gothic period or the Industrial Revolution.

The Greeks

Ancient Greek architecture was a miracle of style, balance, and harmony, with a powerful simplicity whose influence persists in architecture to this day. It is distinctive and immediately recognizable, a graceful massing that creates a sense of dignity, wisdom, and timelessness. The Greeks believed in human intellect and rational thought, in community, and the achievements of the living, rather than the cult of death featured in earlier civilizations. Accordingly, their architectural focus was on public buildings: temples, theaters, civic structures. They were the pioneers of city planning.

Greek society was built upon democracy, stressing the involvement of the individual in government and culture. This was reflected in their architecture. Structures were rarely aligned with one another but were instead set at angles to enhance the individuality of the structures and draw the viewer into participating in the process. The viewer's viewpoint was not strictly regimented, as we will see in later eras, but instead allowed to form naturally.

The elements of classical Greek structures are simple and few, yet carefully organized to create an overall effect. The primary structural form was trabeation—stone columns supporting lintels. There were three styles, or orders, of Greek architecture: the Doric, the Ionic, distinct styles that originated in different parts of the country, and the Corinthian, which is essentially a spin-off of the Ionic order. The structural elements, proportions, and composition of a building were defined by its order. Doric structures, in particular, followed a rigidly prescribed design, evolving toward the ideal Doric form expressed in the Parthenon. Symmetry of proportion runs through the structures, with set ratios of building length to width, and column height, diameter, and spacing. The Ionic style was less rigidly defined than the Doric, though proportion was still important, and the Corinthian order differed from the Ionic only in column design. In fact, the names of the orders are most often associated with the capitals or decorative tops of the columns used in the buildings. Doric columns are simple angled tops, Ionic columns are delicate scrolls, and Corinthian columns are crowned with a delicate, leafy capital.



The Romans

Roman philosophy and engineering fundamentally changed the way people thought about architecture. The Romans took previously invented structural elements, such as the arch and vault, to the limits of their potential. The Greeks, for example, dabbled with concrete and in later periods occasionally used arches, but only as freestanding decorative elements. In the hands of the Romans, these same two concepts were used to build the Colosseum.

The development of the rounded arch was critical to Roman architecture. In our earlier discussion of trabeation, we pointed out the lintel as the weak element of the structure. The tensile strength of the lintel limits the size of the opening and the load that can be carried, because the load on the lintel is only supported at the ends. In the non-supported portion of the lintel, the lines of force are aimed through the lintel to the ground. In an arch, on the other hand, the lines of force from the load are directed through the curve of the arch to the supporting piers, and from there to the ground. The supporting pier strength is limited by the compressive strength of the stone, which is far greater than its tensile strength. Moreover, the form of the arch and arch elements is such that the structure actually becomes stronger with a uniform load placed on top of it.

Rounded arches can be placed in a row to make a barrel vault, which means that a significant amount of space can be roofed over. The Romans developed a number of variations on the barrel vault, changing the way that space could be enclosed. The disadvantage of the barrel vault is that it requires continuous support along the sides, limiting the number of window openings permitted in the sidewalls. One answer to this was the groin vault, a structure consisting of two intersecting barrel vaults. Whereas the weight and force of the barrel vault is carried all along the line of the supporting wall, the groin vault concentrates weight and force in the corners of the structure, permitting a more open space and windows. The hemispherical dome, which can be thought of as an arch in three dimensions, was another variation on roofing. This form appears time and time again in Roman architecture, most notably in the Pantheon.

Another important Roman development was that of improved concrete. For several centuries, a concrete made of lime, sand, and water had been used sporadically by various builders. The Romans added a volcanic ash called pozzolana to their concrete, obtaining a stronger mortar that had the added advantage of setting up in water, allowing underwater construction. The Romans mixed this concrete with gravel or chips of stone and molded it into blocks or even arches and vaults, simplifying construction methods.

The Romans considered architecture differently than the Greeks. The Greeks emphasized structure and form, the Romans emphasized space. Whereas Greek architecture was exterior, focused on the outside, on creating an experience for the viewer, Roman architecture was interior, based on the idea of creating an environment for the inhabitants. The Romans were more pragmatic than spiritual. Rather than focusing on temples, they built sumptuous bath houses, theaters, and other public spaces. Great administrators, they created the basilica to house government offices. The interiors of their buildings focused on space, on creating spaces to serve man, spaces that were emotionally and functionally pleasing. The Romans were also sophisticated urban planners, designing freeform civic centers, or forums, and rigidly styled castrum, a combination military outpost/colonial settlement in newly conquered territory.


Byzantine

After the fall of the western Roman Empire, the creative focus of architecture moved to Constantinople, located at the site of the Hellenic city of Byzantium. Most of the surviving structures from this period are churches. Rather than the long, axial floor plan characteristic of Roman barrel vaulted structures, Byzantine designs tended toward a centralized, vertically focused structure crowned with a dome that flooded the interior with light. Light, form, and structure in these churches were orchestrated to express the spiritual ideas of the new Christian religion, to exalt the worshippers.

Byzantine churches achieved the floating effect of the central dome by the use of pendentives and pendentive domes. A hemispherical dome requires a circular base to support it fully, like that on the Pantheon. Interior spaces, however, tend to be square. Ancient architects wishing to top a non-circular space by a spherical dome added diagonal elements across the corners, called squinches, which helped support the structure. The Romans developed a more sophisticated method of support called the pendentive. A pendentive is a spherical, inverted triangle that rises from its point and curves downward. It is essentially a section of a domed surface and as such can be constructed to fully support a hemispherical dome. More important than the full support, though, is the nature of that support. The structural support of a dome on a cylinder or on squinches is visually dense, giving a sense of massing and of enclosure. A dome on pendentives appears to rise from only four points, giving the impression of floating overhead, adding to the otherworldly effect of the church interior.

The spiritual effect of the floating domes was enhanced by the use of light and ornamentation. Hagia Sophia, the most spectacular of the Byzantine churches, is flooded with light from a multitude of wall openings. A row of windows around the base of the dome adds to the impression of a magically hovering surface, as do the additional half domes and colonnades in the lower levels. To look up from the floor of the building is to look into a gleaming, billowing surface that appears to follow no known rules of structure, generating an exaltation of religion in its intensity.


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