world architecture

Paris France
The Centre Nationale dArt et de Culture Georges Pompidou, commonly known as the Pompidou Center, is in the Marais district of Paris. Initially given the working title Beaubourg (after its site), the center was formally named for its initiator, French president Georges Pompidou (1911 1974), following his untimely death. In December 1969 he announced an international design competition for a monumental multiuse public library, modern art museum, and contemporary arts center. The winning team, chosen from 681 entries, was directed by two architects the Italian Renzo Piano (b. 1937) and the Englishman Richard Rogers (b. 1933). They were assisted by Gianfranco Franchini (one of Pianos erstwhile fellow students), and Ted Happold and Peter Rice of and structural engineering firm Ove Arup and Partners. Rice had been site engineer on the Sydney Opera House. Opened in February 1977, the Pompidou Center was a bold and innovative building redolent of the radical but unbuilt schemes of the Archigram group. Renowned for its highly flexible plan and the external exposure of its structure and services, the Pompidou Center was immediately acclaimed as the Parisian symbol of late-twentieth-century high-tech architecture.In his first year of office, President Pompidou decided that the library proposed by his predecessor Charles de Gaulle should have a broader function. A passionate champion of the arts, Pompidou envisioned a national center that would act as a focus for the extensive array of cultural activities then evident in Paris. He wanted a building complex that would encourage all forms of artistic expression, promote the connection between the arts and social life, and be widely accessible to the person in the street. Flexible and uninterrupted internal spaces were needed to enable exploitation of its multiuse focus and to meet changing needs. The design team coalesced early in 1971, following Happolds approach to Rogers about the competition they had collaborated before. Rogers was then partner with Piano, and they saw Beaubourg as an opportunity to correct their firms bleak work outlook. Piano, based in Genoa, Italy, was an architect and industrial designer. From the mid-1960s he had been experimenting with lightweight shells. One of his projects was the Olivetti plant in Scarmagno, Italy (1968) he also designed the buildings components. He met the Italian-born Rogers in London in the late 1960s, and they collaborated on the Italian Industry Pavilion at the 1970 Osaka Worlds Fair. Rogers had been a member of Englands Team 4 with Norman Foster. Over the next few years Piano and Rogers together produced the ARAM Medical Center in Washington, D.C. (1970), the Fitzroy Street Commercial Centre in Cambridge, England (1970), and offices for the B and B Upholstery Co. in Como, Italy (1971 1973). In several, aspects a totally flexible plan, an external steel structure as the basis of the esthetic, and the use of strong color the latter foreshadowed the Pompidou Center. The vast Plateau Beaubourg, cleared of dilapidated 1930s housing but surrounded by historic buildings, was selected as the site for Pompidous new arts complex. It was being used as a car park for the nearby food markets at Les Halles, then in the process of demolition. The architects retained about half the Plateau as a pedestrian open space, intended for meetings and street theater, as well as gardens and sculpture. The new building was pushed to the eastern edge alongside an existing street. Construction began in April 1972, and Beaubourg was inaugurated by President Valery Giscard dEstaing on 31 January 1977 it opened to the public two days later. Finished on time and under budget, it cost Fr 993 million (then U.S.$100 million). All the Pompidou Centers mechanical services are on the street side on the side facing the open space, external escalators within clear acrylic vaults give access to the buildings impressive interiors. To create uninterrupted internal spaces suited to unlimited uses, the steel-framed structure is outside the building, supporting an internal envelope enclosed by a glass skin. Six floors, 532 feet (166 meters) long and 192 feet (60 meters) wide, with movable suspended partitions, house a spectrum of functions, including a library, an art museum, and an industrial design center. There are also spaces for exhibitions, theater, dance, and musical productions, as well as a cinema, lecture and meeting rooms, a restaurant, and (more recently) an Internet cafe. The Piano and Rogers office designed the furniture, which was sympathetic to the buildings esthetic. Outside, the unavoidably expressed vertical, horizontal, diagonal, and crisscrossed prefabricated tubular steel structural components form grids and lattices to create the architectural composition of the facades. The frame, together with the escalators and circulation walkways, and the service ducts are painted green, blue, red, yellow, gray, or white, according to their function. The building is raised on pilotis doubtless the influence of Le Corbusier creating a covered undercroft with space for shops. A 700-place car park is provided beneath the Plateau. The architects intention was compromised in the realization of Beaubourg for a variety of reasons: the cooler attitude of Pompidous successor, Giscard dEstaing public reaction to the unconventional design and of course the cost. Fire regulations were also an agent of change because the need to provide fire-isolated sections in such a large building confused the plans for total internal flexibility, achieved (according to the design) by having movable floors and walls. One of the abandoned proposals it had impressed the competition jurors was the display of information from the structural frame in the manner of Oscar Nitzchkes proposal for the unbuilt Maison de la Publicite (1932 1935). A lit screen was investigated but costs were prohibitive. Like the Eiffel Tower (1889), the Pompidou Center, while provoking controversy for its eccentric design, was a highly successful tourist attraction. Daily visitor numbers soon reached 20,000, four times the predicted traffic. Having welcomed some 160 million people in its first twenty years, the Center was closed for renovations from late 1997 until January 2000. Piano and Jean-Francois Bodin, designer of the Musee Matisse in Nice (1987 1993) and the renovated Musee dArt Moderne de la Ville de Paris (1992 1994), jointly supervised the Fr 576 million (U.S.$92.75 million) project. Essential maintenance including painting was carried out, the building and its infrastructure were modernized, and additional exhibition spaces were created by the removal of offices to an off-site location. A more orderly approach was taken to the use of the internal spaces by rationalizing use patterns. Access to the library from the

Qosqo (navel or center) in southern central Peru was once the ancient capital of the Inkan Empire. Continuously occupied for three millennia, the oldest living city in the Americas perches 11,150 feet (3,400 meters) above sea level in the Andes Mountains. Strategically located, Qosqo reached out to the entire Tahuantinsuyu (Land of the Four Quarters) by means of an extensive road network. In the days of its glory, the city boasted about 100,000 houses and somewhere between 225,000 and 300,000 citizens, many of whom lived in the neighboring farmland. The population compares with modern Rochester. Jersey City, or Anaheim. It was remarkable for its physical planning, its social organization, and the gold-festooned buildings of massive masonry that adorned it. Farmers and herdsmen of the Marcavalle culture established permanent settlements in the Qosqo Valley around 1000 b.c. The Chanapata followed 200 years later, and successive groups Qotakallis, Sawasias, Antasayas, and Wallas also occupied the site for about six centuries from a.d. 600. There is a tradition that Inkan Qosqo was founded some time in the eleventh or twelfth century by the legendary king Manco C

Greenwich England
The Queens House on the edge of the Royal Park at Greenwich near London was designed by Inigo Jones probably the greatest of all English architects early in the seventeenth century. It was a major architectural feat because it represented, all at once and in a single building, the introduction of a new kind of architecture in the face of a well-established and reactionary building industry. Before Jones (1573 1652) stepped on her architectural stage, England had been trying for almost a century to come to terms with the new forms of the Italian Renaissance. Henry VIIIs attempts to bring Italian craftsmen to England had been resisted by his subjects, and his later breach with most of Catholic Europe had stemmed the inflow of artistic ideas. The cultural standoff was maintained through Elizabeth Is long reign and well into the seventeenth century. Anything of the Renaissance that did reach England came, often in clumsy caricature, through northern European pattern books, and attempts to use supposedly Italian details in English architecture generated the epigram. The Englishman Italianate is the devil Inkarnate. Single-handedly, Jones changed that.His early life is obscure, but in 1603 he was working for the Earl of Rutland. Two years later Anne of Denmark, James Is queen, asked him to design scenery and costumes for a royal masque at the Palace of Whitehall. In 1611 1612 he briefly held the office of Surveyor to the Crown Prince, Henry, and shortly after his masters death, he was promised the position of Surveyor of the Kings Works. The following year Jones traveled in Italy with the Earl of Arundel and visited Venice, Vicenza, Bologna, Florence, Siena, Rome, and Genoa. He was impressed with modern Italian architecture and especially the country houses designed by Andrea Palladio (died 1580). He bought a copy of Palladios The Four Books of Architecture, published in Italian in 1570. Soon after returning to England Jones succeeded Simon Basil as Surveyor. His first royal architectural commission was for the Queens House for Anne of Denmark. James I often went down from London to Greenwich (perhaps for fear of the plague) where Pleasaunce Palace stood on the site of the present Royal Naval College. Anne wanted a villa linking the palace garden and the Royal Park, which were divided by the main road between Deptford and Woolwich. Jones built the house with a two-story wing on each side of the road, joined at the upper level by a bridge, making it possible to pass from the palace gardens into the park without crossing the thoroughfare. When Anne died in 1619 work was halted. The basement and unfinished ground floor walls were covered with straw to protect them from frost, and a decade passed before work resumed. In 1629 Jamess son Charles I gave the house to his queen, Henrietta Maria, and Jones completed it for her. By 1635 the outside was almost finished. Apart from its ingenious siting, the house was un-English in a number of ways, most notably for its carefully proportioned H-shaped plan, that contrasted with the rambling layout of contemporary English houses. Spatial organization within the Queens House was symmetrical, geometrically laid out in keeping with the principles of visual harmony set down by Palladio. The Great Hall at the buildings core was a 40-foot (12-meter) cube, the pattern of its marble floor matching the geometrical composition of the ceiling panels. From one corner of the hall, the so-called Tulip Stair the first cantilevered staircase in England and of the kind recommended by Palladio led to the kings and queens separate apartments on the upper floor. Each suite comprised rooms planned to fit the court routine: a presence chamber, anteroom, privy chamber, antechamber, bedchamber, inner closet, and outer closet. A loggia on the south side of the house looked out across the Royal Park. Another major departure from convention was the outside appearance of the house. The park front had a loggia in the center of the second story, and the proportions of solids and voids can be related to Palladios Palazzo Chiericati at Vicenza (1550 1580). The riverfront had a central full-height projection to relieve its flatness a horseshoe stair led from the palace garden to the podium on which the Queens House stood. The building was crowned with a balustrade. The plain upper walls were set above a ground floor with regular, deep recessed joints. The stories also had windows of different heights, but in the eighteenth, century the ground floor windows were lengthened. All is not what it appears, because the house is built of brick covered with white stucco in imitation of stone and prompting the alternative name the White House. Although Jones believed that the outside of buildings should be solid, proportionable to the rules, masculine and unaffected, the interiors were a different matter, and the Queens House was lavishly decorated and fitted out. The ceiling panels of the Great Hall, showing Peace surrounded by the Muses and Liberal Arts, were painted in 1635 by the Italian father-daughter team Orazio and Artemisia Gentileschi. Henrietta Maria furnished the rest of her house so opulently that an impressed visitor exclaimed that it far surpasseth any other of that kind in England. But the fact was there was no other of that kind in England. The interior was possibly incomplete when civil war erupted in 1642. When the kings houses were seized by Parliament in the following year, Joness surveyorship was terminated. In 1645 he was arrested and his property confiscated that was put right a year later. The king was executed in 1649, and Jones died (some say of grief) in 1652. Anti-Catholic feelings compelled the queen to flee the country. Following the restoration of the monarchy in 1660, Charles II intended to live in the Queens House while building a new palace, but Henrietta Maria (now Queen Mother) moved in and remained until her death in 1689. Joness student and nephew John Webb undertook the restoration of the house in 1662, following his uncles meticulous documentation and adding two bridges to make the plan of the upper floor into a perfect square. In 1690 the Queens House became the residence of the Ranger of Greenwich Park, and in 1708 the ground floor windows and original casements were altered, spoiling Joness careful design. The house was painstakingly restored in the 1980s. It is difficult for us to grasp how innovative, even alien, the white, classical Queens House would have appeared in Stuart England. Inigo Jones had categorically departed from every English precedent, and his design was regarded by one critic as some curious device, because no one understood the theory upon which his architecture was based. His lead would not be followed for a hundred years. His architectural feat was achieved for a number of reasons: first, he was a new kind of architect, with royal patronage second, he was no slave to fashion but had a thorough commitment to the principles that underlay Italian Renaissance architecture and third, he was a practical man with consummate drafting skills that allowed him to communicate exactly what he required of the craftsmen, although they were unfamiliar with his kind of architecture.

Bexley Heath England
Designed for William Morris in 1859 by his friend and coworker Philip Webb, the Red House in the London suburb of Bexley Heath has been called a cornerstone in the history of English domestic architecture. Much more than that, although in one sense a piece of eclectic architecture, it was a milestone in the way that architects designed houses, making the house to fit the occupant, rather than (as had been the case) forcing the occupants to fit the house: the earliest glimpse of functionally constrained design. Early in the twentieth century the German critic Hermann Muthesius recognized it as the first house to be conceived as a whole inside and out, the very first example in the history of the modern house. At that moment, the ideas behind it were taken up and developed by the American architect Frank Lloyd Wright and fed back into the European Modern Movement. The now-famous English social reformer, designer, novelist, and poet William Morris (1834 1896) originally intended to become a Church of England priest. While at university he decided to devote himself to art. He then worked briefly for the Gothic Revival architect G. E. Street, but influenced by the Pre-Raphaelite painters Edward Burne-Jones and Dante Gabriel Rossetti, soon turned, also briefly, to painting. In 1857 he met Jane Burden, one of Rossettis models, and two years later they were married in Oxford. Morris was financially independent his annual income of

Berlin Germany
The restored Reichstag in Berlin, designed by the London architectural firm of Foster and Partners, epitomizes a new kind of architecture one that respects the physical and cultural environment and takes account of the past while assuming responsibility for the future. The institution known as the Reichstag was set up in 1867 by the German Chancellor Otto von Bismarck to allow the bourgeoisie to have a role in the politics of the new empire, a confederation of princely states under the King of Prussia. From 1871 the Reichstag met in a disused factory until a neo-Renaissance building (1882 1894) was created for it by the Frankfurt architect Paul Wallot. After the reunification in 1990, the new Germanys Parliament, comprising the two houses known as the Bundestag and Bundestat, made Berlin the capital of the Federal Republic of Germany in June 1991. It also voted, by a small majority, to move its own seat from Bonn to Berlin, locating it in the historic building. The monument was in a sorry state and held memories of the failure of the Weimar Republic and the disastrous Third Reich. Before the notorious Berlin Wall came down, it was cut off from the old center, just outside the boundary now it is in the middle of the city. The Reichstag building had been patched up in the cold war years, and the facades and the interior underwent desultory restoration in the 1960s. It was used as a historical museum between 1958 and 1972, and spasmodically for meetings of the West German Parliament. In June 1992 an international architectural competition was held to restore the Reichstag, and eighty architects submitted proposals. Following some debate and a second stage of the competition among the three shortlisted entries, Foster and Partners were awarded the commission in July 1993. The consulting engineers were Leonhardt Andra and Partner, the Ove Arup Partnership, and Schlaich Bergermann and Partner. The Foster partnership originally proposed a huge mesh canopy supported on columns to enclose Wallots building and extend it into the Platz der Republik. Axel Schultes and Charlotte Franks urban plan for the Spreebogen district of Berlin, the result of a contemporary competition, set the framework for new buildings and called for a rebriefing and consequent changes to the design. Building work began in July 1995 and the new Reichstag was opened in April 1999 it cost DM 600 million (approximately U.S.$330 million). According to the architects, their final design was constrained by four factors: the history of the Reichstag, which in its earliest days had symbolized liberty the day-to-day processes of the Parliament questions of ecology and energy: and (naturally) the economics of the project. Because Wallots building was to be preserved as far as possible, the Reichstag is a living historical museum that frankly shows the scars of its past pockmarks caused by shells, charred timber, and Russian graffiti from the post World War II occupation are all left visible. Because it was believed that the processes of democracy should be transparent, Wallots formal west entrance was reopened to serve for all users of the building, politicians and public alike. The great steps lead to a tall, top-lit narthex on entering, the visitor is confronted by a glass wall that defines the lobby beyond that, another transparent partition gives a view into the parliamentary chamber. Members of the public may occupy public balconies or follow interlocking spiral ramps to a viewing deck that looks down into the chamber from within the cupola. The functional needs of the Parliament required the demolition of many of the accretions of the earlier refurbishment.Visually and structurally, the design is dominated by a new glass-and-steel hemispherical cupola at the center of the restored building, which replaces and evokes the war-damaged original dome, removed in 1954. But the cupola is more than an esthetic or symbolic choice. At its center a curving, inverted cone of mirrors reflects daylight into the plenary chamber. The cupola is fitted with a movable sunscreen: in summer it tracks and blocks the sun to prevent overheating of the interior in winter it is set aside to allow warming sunshine to penetrate into the building. The cone also acts as a convection chimney fresh air enters the building through air shafts and rises through the floor of the chamber. As it heats up it is drawn into the cone, and an extractor expels it from the building. An aquifer at a depth of 100 feet (30 meters) stores cold water that is circulated through pipes in the Reichstags floors and ceilings in the summer. Warmed in the process, the water is then pumped into another subterranean lake, 1,000 feet (300 meters) beneath Berlin. At that depth it retains its heat, and in winter the process is reversed to heat the building. The Reichstag power plant that drives the pumps is fueled by renewable grape seed oil. In the 1960s the restored Reichstag emitted 7,700 tons (7,000 tonnes) of carbon dioxide a year the new building emits 440 tons. Germany has been a world leader in energy conservation, and the building that now symbolizes national unity fittingly exemplifies that mind-set.

Concrete is a combination of small aggregate (sand), large aggregate (gravel), a binding agent or matrix, and water. Historically, lime was used as a matrix, mostly for mortars that had no large aggregate. In 1774 the British engineer John Smeaton added crushed iron-slag to the usual quicklime-sand-water mix, making the first modern concrete for the foundations of the Eddystone Lighthouse off the English coast. Fifty years later, a new matrix was discovered. Portland cement, a calcium silicate cement made with a combination of calcium, silicon, aluminum, and iron, is the basis of modern concrete. In 1824, the English stonemason Joseph Aspdin made it by burning (on his kitchen stove) finely ground limestone and clay, then grinding the combined material to a fine powder. It was named for its original use in a stucco that imitated Portland stone. However, the burnt clay yielded silicon compounds that combined with water to form a much stronger bond than lime. It was to revolutionize the architectural and engineering world. For the next thirty years or so, plain concrete, because of its tremendous compressive strength (resistance to crushing), was used for walls. Sometimes it replaced brick as fire-resistant covering for iron-framed structures. Reinforced concrete, developed first by the French, combines concretes compressive strength with the tensile strength (resistance to stretching) of metal at first, iron and later steel reinforcing bars or wire. The first person to employ such construction was the Parisian builder Fran

Swindon England
High-technology (usually contracted to high-tech) architecture was a movement born in the 1960s and sustained through the 1980s. It sought to express zeitgeist the spirit of the age defined by its followers as resting in the technological advances of industry, communications, and travel, including aerospace developments. These advances offered an alternative building approach. High-tech architects produced machinelike structures of flexible plan, applying lightweight materials such as sheet metal, glass, and plastic to innovative structural techniques they employed easily assembled, sometimes mass-produced, building components. Usually, the structure was made explicit (often reinforced by colorful paintwork). Sometimes the services were exposed. Constructed between 1980 and 1983, the Renault Distribution Center at Swindon, about 100 miles (160 kilometers) southwest of London, was and continues to be regarded as the archetypal high-tech building. The brief called for a building that established a progressive corporate identity and stood out from the featureless industrial shed typical of the area. It was to suit multiple functions, be quickly constructed, and capable of later extension. Architect Norman Foster of Foster Associates, together with the engineering firm of Ove Arup and Partners, responded with a design for a visually arresting, structurally self-explicit building that dominated what has been described as an otherwise bleak landscape. Foster was born in 1935 in Manchester, England. He trained as an architect and town planner at the University of Manchester (1956 1961) before undertaking a masters degree in architecture at Yale University (1961 1962). Soon after, following a brief period with Richard Buckminster Fuller, he returned to England to set up practice with his wife Wendy and Richard and-Su Rogers. They worked as Team 4 between 1964 and 1967 until the partnership was superseded by Foster Associates, now Foster and Partners. In the late 1960s Foster and Richard Rogers made a significant architectural statement at Swindon with the Reliance Controls Factory (1967), one of the last Team 4 projects. Its elegance, use of off-the-shelf components, exposed steel structural bracing, metal cladding, wall-high glazing, flexible plan, and focus on improved employee working conditions all challenged the conventional wisdom about industrial buildings. Reliance Controls was an early example of high tech. Almost two decades later the Swindon landscape was again confronted this time by the unconventional form of the Renault Center. Brilliant yellow (Renaults corporate color) cable-stayed tubular steel masts supported a reinforced polyvinyl chloride (PVC) membrane roof that covered spaces for spare parts warehousing, visitor reception, distribution and regional offices, vehicle showroom, after-sales maintenance training, and staff dining. Its expressive, detailed outline and functional, worker-friendly spatial arrangements were characteristically Fosteresque, balancing the high-tech approach with client and social needs. In its marketing literature, Renault enthusiastically reproduced images of its marqueelike center, regarding it as the quintessence of its corporate image. When presented with plans for the sloping 16-acre (6.5-hectare) site, the local authority consented enthusiastically to the unexpected design and to the proposed 67 percent land coverage (the usual limit was 50 percent). The prefabricated rectangular building was formed as a series of suspended modules forty-two in total comprising 52-foot-high (16-meter) masts, connected to pin-jointed portal frames. Each module measured 91 feet (24 meters) square and was 25 feet (7.5 meters) high at the edge and 31 feet (9.5 meters) in the center. As extensions were required, modules could be unbolted and new ones added. Initially, thirty-six modules were devoted to warehousing, the rest located at the narrower end of the site where the building tapered to a generous entry and porte cochere. The fully exposed, repetitive mast arrangement flowed graciously beyond the external walls, glazed for showroom and dining but sealed elsewhere with steel skins. Ample natural lighting was achieved by clear glass panels inserted where the mast pierced the roof membrane and by a louvered roof light at the apex of each module the louvers could be opened for ventilation. The building was centrally heated and lit according to the function of the space. Foster Associates designed the furniture. The Renault Distribution Center has been described as ushering in the firms Hong Kong and Shanghai Bank headquarters (1979 1986) in Hong Kong, also noted for its extrinsic structural expression. However, unlike the sprawling Renault building, the bank headquarters is a soaring triple-layered tower (the tallest forty-one stories) with immense tubular steel trusses from which the floors are suspended. Many consider tins Fosters magnum opus.

The Houston Astrodome in Texas, opened in 1966, was the first stadium with a roof over the playing area. It set a trend for sports fields for the next twenty years. Its roof, designed to resist 135-mph (216-kph) winds, has a clear span of 642 feet (196 meters) it is 208 feet (64 meters) high at the apex. It was not, however, the first arena to have a roof. It was predated by almost 2,000 years by the Flavian Amphitheater in Rome, better known as the Colosseum. The Colosseum measured 620 by 510 feet (189 by 156 meters), and the perimeter of the fourth story had stone brackets supporting wooden masts from which an awning (velarium) was suspended across the interior to shield spectators from the sun. The velarium, was not fixed teams of sailors handled the rope-and-pulley system that allowed it to be opened and closed depending on the weather. The Toronto SkyDome, designed by architects Rod Robbie and Michael Allen and inaugurated in June 1989, was the first modern stadium with a fully retractable roof. SkyDome provides 2 million square feet (186,000 square meters) of usable floor space for up to 30,000 spectators. The 8-acre (3.24-hectare), 11,000-ton (10,000-tonne) roof rises 282 feet (86 meters) above the field level. It consists of a fixed panel and three movable panels, framed with steel trusses and covered with a polyvinyl chloride (PVC) membrane laminated to an insulated steel sheet, moving on a system of tracks and bogies. The roof can open in twenty minutes to uncover the entire field area and over 90 percent of the seating. Since SkyDome, many similar structures have developed the new technology that enables very large buildings, once considered static, to become (at least in part) flexible an architectural feat. Amsterdam Arena, the Netherlands, was opened in September 1996, the first retractable roof stadium in Europe. The stadium is 540 feet (165 meters) wide and 770 feet (235 meters) long the roof, soaring 255 feet (78 meters) above the playing field, consists of two movable panels that retract across the short span. The designer was Rob Schuurman. Bank One Ballpark in Phoenix, Arizona, designed by Ellerbe Becket, was completed in early 1998. Two 200-horsepower motors open or close the retractable roof over the 48,000-seat stadium in under five minutes. Each half of the roof consists of three movable trusses that telescope over a fixed end truss. Either side can be opened to any position, independently of the other. The 52,000-seat Colonial Stadium in Melbourne, Australia, was opened in 2000. Its 540-foot-span (165-meter) retractable roof, employing a lightweight space-truss structure, opens or closes in less than eight minutes. Other arenas, such as the Sports Park Main Stadium of the Oita Prefecture, Japan, and Miller Park, Milwaukee, Wisconsin, were completed in 2001. The former, designed by Kurokawa Kisho Architectural Urban Design and the Takenaka Corporation, has a retractable 895-foot-diameter (274-meter) hemispherical steel-framed shell roof Miller Park has a seven-panel roof.

Concrete is made by mixing broken stone or gravel and sand (aggregate), a bonding agent, and water, and allowing the mixture to harden through chemical process into a solid mass. So-called cementitious materials had been used in ancient Egypt about 3,000 years earlier and later by the Chinese, Minoans, and Mycenaeans, but this synthetic stone a new building material was developed and exploited by the Romans from about the third centuryb.c. Ambrose advised his protege Augustine: When in Rome, live as the Romans do when elsewhere, live as they do elsewhere. Throughout the Roman Empire, the architecture they built was a weighty presence imposed upon the subject peoples a consistency probably more to serve the colonizers, isolated from the familiar things of home, rather than for the colonized. Throughout history architecture has provided a social anchor for migrant peoples. The Roman way was to come, to see, to build, and there was, especially in the days of imperial expansion, a need to build quickly and in a familiar way. That was made possible by the use of concrete. The Romans used concrete (opus caementicium) for all parts of their structures: foundations, walls, and roofs. It was made by combining pozzolana (a volcanic earth found in many places in southern Europe) with lime, broken stones, bricks, tufa, and sometimes pumice. Such a mixture could set even underwater. Lime was obtained by crushing limestone or seashells, or sometimes replaced by gypsum as a binding agent. The Romans placed a very dry mix of pozzolana and wet lime, layer for layer, over rock fragments, and carefully tamped it into place. Its structural strength depended upon what is now called the water-cement ratio: the higher the proportion of bonding agent to water, the stronger the concrete. The combination of a dry mix and thorough consolidation made the material extremely durable. At first, concrete was limited to places where it would not be seen. For foundations, it was placed between wooden form boards that were stripped once the mixture had hardened. For building above the ground, its brutal appearance, once the formwork was removed, presented an esthetic problem. Because the many advantages strength, versatility, economy, availability, and speed of erection more than offset that single disadvantage, the Romans simply used more presentable materials to face the concrete, usually as a lost formwork. For example, as late as 20 b.c. the architectural theorist Vitruvius recommended building two face walls of squared stone (opus quadratum), 2 feet (0.6 meter) thick, tying them together with iron cramps, and filling the cavity with tamped concrete. But that was for prestigious buildings, and a number of alternative wall constructions had already been developed. From around 200 b.c., slabs of volcanic tufa were used as permanent facings far more common was the technique known as opus incertum, which employed small, random pieces of tufa, carefully packed together. Over time the shapes were made increasingly regular, and by about 50 b.c. 4-inch-square (10-centimeter) pyramidal tufa blocks were employed. Set diagonally, their sharp apexes penetrated about 10 inches (25 centimeters) into the concrete infill, providing an excellent bond. Because of its netlike appearance, the method was called opus reticulatum. By then, fired clay bricks were also being used for facing. Over the next two centuries the predominant technique was opus testaceum, flat slice-of-pie-shaped bricks, tied at intervals with bonding courses through the wall. The late empire saw a further variation, called opus mixtum, consisting of alternate courses of brickwork and small squared stones. It is stressed that these systems provided only a presentable surface: the real work of the wall was done by the immensely strong concrete mass, which normally supported innovative superstructures, also made of concrete. Unfinished concrete was not only unattractive to the eye but it also presented an architecture that was, to the Roman mind, inappropriate in appearance. They therefore covered it, whether brick faced or not, with a variety of decorative surfaces: stucco (a mixture of marble dust and lime) perhaps 3 inches (7.5 centimeters) thick in up to five layers, and molded, patterned, painted, and sometimes veneered with mosaics of marble and even glass tesserae. The most important buildings had marble veneers, held in place by bronze pins and nonstructural architectural orders applied as pilasters or half-columns that masked the concrete structure and reduced the visual scale. Roman public architecture existed to move in and through, rather than around. Such urban buildings as the thermae (bathhouses) and basilicas (law courts) demanded interior spaces uncluttered by columns that could accommodate huge gatherings of people. In order to achieve vast interior spaces, the Romans exploited the semicircular arch, a technology inherited from their Etruscan forebears. The arch and its three-dimensional extensions, the vault (a prismatically extended arch) and the dome (a rotated arch), could span large distances without intermediate supports. With characteristic directness, Roman engineers found expedient solutions. A small rectangular room could be covered by a semicircular barrel vault carried on continuous parallel side walls. A square room could be roofed by a cross vault (two barrel vaults placed at right angles), supported by piers at the corners and allowing the space to be lit from all sides. Larger rectangular spaces could be enclosed by a procession of such vaults built side by side. A polygonal space received a hemispherical dome and an apse a half-dome, carried on drums above the base walls. By using concrete for these roof structures, the Romans enclosed volumes that would not be equaled for over 1,000 years. The simplest barrel vaults consisted of a series of parallel brick arches cross-tied as in opus testaceum and filled between with concrete that is, the concrete was packed into brick compartments. The whole structure was supported by wooden centering until the mortar had set. Other vaults and domes were directly formed in mass concrete. The technique had two main advantages: once the centering was designed and placed, it employed unskilled labor, and it enabled complex plan forms to be roofed without the cost of dressed stone construction. Often, the weight was reduced by using hollow clay boxes or even wine jars, especially in the groins of cross vaults alternatively, vaults were lightened by forming recesses or coffers in their undersides. Domes were generally much thicker toward their base and therefore appeared externally as inverted saucers, while inside they were hemispherical. As they rose, lighter materials, such as pumice a stone that floats were used for aggregate. In order to underline the achievement of the Roman engineers and architects, it is helpful to consider the size of some concrete structures a couple of examples may suffice. The concrete barrel vaults that spanned the 76-foot-wide (23-meter) side aisles of the fourth-century-a.d. Basilica of Maxentius in Rome were 8 feet (2.45 meters) thick. The 142-foot (43-meter) concrete dome of the Pantheon, also in Rome, is 4 feet thick (1.3 meters) at its apex and 20 feet at its base. The massive loads of these roofs were carried to the ground through huge piers or thick walls, and their horizontal thrusts resisted by buttressing elements integrated with the architectural design.

Saltash England
The Royal Albert Bridge at Saltash, completed in 1859, was Isambard Kingdom Brunels last bridge and probably his finest work. Certainly, it was one of the great engineering feats of the nineteenth century, because (it is widely agreed) of its size, its economy of design, its revolutionary superstructure, and not least because of the way in which Brunel solved difficult logistical problems. It was one of the first bridge projects on which compressed air was used to allow underwater foundation work to proceed. Dividing Cornwall from the rest of England, the tidal reaches of the River Tamar were once a major maritime thoroughfare. The twelfth-century port of Saltash lies on the west shore of the Tamar Estuary near the English Channel coast, nearly facing Plymouth on the opposite side. A railroad into Cornwall, the county in the extreme southwest of England, was first proposed in 1844. The Cornwall Railway Company was formed in 1845, and it successfully applied for the necessary act of Parliament to provide either a steam ferry to transport trains across the 1,100-foot-wide (336-meter) 85-foot-deep (26-meter) river or to build a bridge. The project was delayed because the Admiralty was concerned about restricted access to the Devonport naval base, close to Saltash. Finally, in 1852 Brunels proposal for a bridge with two main spans was adopted because a single pier in the river would offer least hindrance to water traffic. During the construction the plans were changed for financial reasons Brunel designed the bridge for a single-track railroad. The authorities demanded a clearance of 100 feet (31 meters) under the bridge at high tide.The Royal Albert Bridge is 2,240 feet (683 meters) long. Each of the two main spans is 455 feet (140 meters), and the 17 side spans of the long, curving approach viaducts vary between 70 and 90 feet (21 and 28 meters). Brunel first proposed a single-span bridge but because of difficult ground conditions changed the design. Brunel found a firm base on rock in the middle of the river for the center pier, at a depth of more than 87 feet (27 meters) below high-water mark. Debris had to be cleared to expose a good foundation. To that end, a. 95-foot-tall (29-meter) iron cylinder, 35 feet (11 meters) in diameter, was fabricated onshore. A dome was constructed about 20 feet (6 meters) above its lower end, and a 4-foot-wide (1.2-meter) gallery, divided into 11 compartments, was built around the cylinder below the dome. The cylinder was floated into position and sunk to the riverbed in June 1854. Compressed air was fed into only those compartments where men were working, obviating the need to supply it to the whole space under the dome all the time. The foundation was cleared, and the rock was leveled with a 16-foot-thick (5-meter) base layer. By the end of 1856 the circular granite center pier was completed to a height of 12 feet (3.7 meters) above river level. Four hollow octagonal cast-iron columns, 10 feet (3 meters) in diameter and stiffened by cross-bracing, rise from the center pier to the same height as the tapering masonry piers at the ends of the approach viaducts. Two columns support each of the huge main trusses. Those trusses were fabricated on the riverbank. Each comprises a curved, wrought-iron elliptical tube 16.75 feet (5.1 meters) wide constrained by the single-track railroad and 12.25 feet (3.7 meters) high, forming a flat arch that carries the weight of the superstructure. The arch is connected to massive catenary iron chains at eleven equidistant points by pairs of vertical standards, braced by diagonal bars the chains support the girders under the railroad deck, 110 feet (34 meters) above high-water mark. Beginning on 1 September 1857, the first 1,200-ton (1,016-tonne) truss was floated into position on four pontoons. Through the combined efforts of 500 men on shore and on five vessels at strategic points in the river, it was put into place with great accuracy. As the masonry pier progressed, the truss was raised a little at a time by hydraulic jacks. By July 1858 it had reached its full height, and the second was ready for floating into position. The process was repeated for the second truss. At their landward ends, the trusses are carried by piers, with arched openings through which the railroad passes. The bridge was opened by Queen Victorias consort, Prince Albert hence the name on 3 May 1859, just a few months before its creator, Brunel, died. Its construction made possible a continuous rail journey between London and Truro. A branch line to Falmouth opened in 1863 and was later extended to the new docks then being built. A neighboring suspension bridge carrying the A38 road over the Tamar was completed in 1961. Early in 1998 the Royal Albert Bridge was refurbished. The