The Aluminum rods of British Pavilion in Shanghai are void or soild?

Friday, September 24, 2010

Sagrada Famillia

“An End in Sight for a Centuries-Old Building Project?”

By Josephine Minutillo

In recent years, ramped up efforts and state-of-the-art technology have speeded construction at Barcelona's famously unfinished Sagrada Família Church

hartres Cathedral’s imposing spires, rising heroically above the wheat fields in the countryside southwest of Paris, are a testament to the interminable construction that went into Medieval churches. While the shorter spire was begun in the 12th century, its taller, more flamboyant neighbor was not completed until some 400 years later. The campaniles of Barcelona’s Sagrada Família (Holy Family) church are equally impressive, and along with the cranes that hover above them, represent the most visible elements of an unmissable construction site in the center of a bustling metropolis—a unique, modern-day example of a complex building more than 125 years in the making.

Unlike Romanesque and Gothic cathedrals, in which the master builder remains largely unknown, the Sagrada Família is the vision of one very well-known architect—the eccentric Catalan Antoni Gaudí, whose Modernista buildings created a sensation in fin-de-siècle Barcelona. But much like Chartres, which battled destructive fires on numerous occasions, construction of the Sagrada Família suffered huge setbacks during the devastating Spanish Civil War in the decade after Gaudí’s death in a streetcar accident in 1926. Crucial drawings and building models were lost during the conflict, making Gaudí’s ultimate vision for the temple less clear for his successors. Efforts to interpret that vision have been the source of controversy ever since. (Manifestos are presented every few years urging a halt to construction, claiming the building as it exists today is just a caricature of Gaudí’s work.)

While progress on the building in the decades that followed may have seemed slow, less than 10 percent of the planned church had actually been built during Gaudí’s lifetime. (The first stone was laid in 1882, a year before Gaudí was appointed architect.) The continuation of construction depended on several factors, not least of all funding. As an expiatory church, the Sagrada Família relies entirely on private donations; no money is received from the government or Catholic Church. When more towers began to rise, slowly revealing what would be Gaudí’s most radical design, the construction site gained increasing appeal as a tourist destination. The donations of a steady stream of visitors—nearly 2.5 million annually—coupled with advances in construction technology, have brought astonishing progress to the building in recent years.

Among the technological advances is a “file-to-factory” construction system. Since the usual trinity of plan, section, and elevation was not sufficient to translate Gaudí’s unusual forms to the stone masons who would create the building elements by hand, intricate scale models were needed to illustrate the components’ irregular structure and fanciful shapes. Today, complex computer drawings feed information to a stone-cutting machine and other fabricators, thus eliminating one of the most time-consuming aspects of the building’s earlier construction.

But the surviving pieces of those early models proved invaluable for determining—beyond a doubt, in the opinion of some—Gaudí’s audacious design. “If the Casa Milà had been left half-built and the models partially destroyed, there would be no hope whatsoever to restore it according to Gaudí’s wishes because it was a free-form building,” says Mark Burry, referring to Gaudí’s famous apartment complex in Barcelona’s Eixample district, begun in 1905. Burry, a professor at the Royal Melbourne Institute of Technology (RMIT), in Australia, has written and lectured extensively on the Sagrada Família. His involvement with the project began 30 years ago, when in a student thesis project he himself questioned the contemporary builders’ authority to continue construction.

According to Burry, Gaudí began to use a codex of very rich geometries in his last years. Some model fragments contain important information, like the intersection of three surfaces, or triple points. Enough of these triple points exist, along with photographic documentation of lost models, to provide strong evidence for the final design. “Gaudí came up with a language which allows us to readily assimilate the role of his successors,” Burry explains. “If he hadn’t used this language, we would have been inventing for ourselves, and the criticism that the building gets from time to time would be valid. But what has been built after his death has come directly from this evidence, so there’s no question of its being somebody else’s interpretation of what Gaudí would have done.”

Up until the early 1980s, architectural work at the Sagrada Família was overseen by former collaborators of Gaudí’s, who were well past retirement age by then. The current head architect, Jordi Bonet, was also privy to firsthand accounts of Gaudí’s design process from his father, Lluís, another collaborator. But Bonet says that kind of intimate knowledge of the project is not necessary to continue with construction in the future. “Gaudí knew it would be impossible to finish the church within his lifetime,” Bonet explains. “So he developed a new architecture that was different from his previous work. It is a synthesis of form and structure based on geometry. And because geometry is an exact science, we can build it today precisely the way Gaudí pictured it in his head.”

udí did, however, draw on the knowledge he gained from earlier projects: in particular, the crypt for the Colònia Güell chapel, another unfinished religious structure built for a worker’s village outside Barcelona. It was for this project that Gaudí developed his famous hanging model—one of the first known adaptive or parametric models—using small bags of birdshot attached to an adjustable web of string. His invention allowed gravity to inform the structural design. But while Gaudí created the somewhat irregular, circular plan for this chapel, he had to work within a Gothic Revival Latin Cross plan already in place at the Sagrada Família. “If you liberated the design to allow gravity to truly inform it, it wouldn’t necessarily conform to bays of equal length, and the proportional system of the Sagrada Família would have been compromised,” says Burry. “But Gaudí used the same principle, relying on the static resolution of forces. The lessons he learned from the Colònia Güell chapel were applied to the Sagrada Família to the extent that the columns, where possible, are aligned to take forces axially, and that accounts for the branching.”

It also accounts for the fact that none of the columns in the Sagrada Família are completely vertical. Even the soaring, treelike columns that run the length of the central nave (reaching heights of close to 150 feet) are slightly inclined. While none of these columns were built before Gaudí’s death, existing plaster models show Gaudí’s experiments with counter-rotated columns (whose profile transforms from circular to square to star-shaped along its length) and structural trees (whose upper branches carry and distribute the load from the vaults, thus eliminating the need for exterior buttressing like most Gothic cathedrals). Just prior to branching, the column forms a node, or knot, which is based on a variety of forms varying from ellipsoids to more abstract formations.

The columns’ upper branches also serve to connect with the ceiling vaults in a novel way. “Gaudí sought a continuity between the columns and vaults in parabolic and spiral column forms,” says Jordi Faulí, assistant head architect. “He did not achieve this with total success until he created the counter-rotated double-helix and adopted the hyperboloid for the skylights of the vaults.” The vault is organized in concentric circles around a large central hyperboloid which is 13 feet in diameter. Columns and skylights alternate in these concentric circles. In planning the vaults of the central nave, which were built during the 1990s, Gaudí used regular surfaces based on hyperboloids to form the oculi and capitals, and hyperbolic paraboloids for the transitional elements between them.

The hyperboloid is one of several ruled surfaces—surfaces, like cones and cylinders, generated by connecting line segments between corresponding points—Gaudí employed at the Sagrada Família. (Similar geometries can be found at Colònia Güell, where he used hyperbolic paraboloids extensively.) But Gaudí was working without precedent, never having seen a building with a significant array of ruled surfaces. He also did not explain in sufficient detail how he intended to translate them into built form, leaving his successors with a substantial challenge—one that has been met by the use of parametric modeling.

The Sagrada Família’s incorporation of such complex forms lent itself to the emerging digital technology of the late 1980s, an undertaking spearheaded by Professor Burry. “Trying to draw Gaudí buildings is a very thankless task,” Burry says from experience. “I have become the only person on the project to work on both analog drawings and digital modeling.”

The first digital model was produced in 1989, but architectural software proved insufficient for resolving Gaudí’s interweaving geometries. By the next year—and concurrently with Frank Gehry’s office—Burry’s team was creating models using advanced surfacing software designed for the aeronautical industry. (Today, the team of architects and engineers in Barcelona uses a combination of programs including CATIA, Rhino, and Mechanical Desktop by Autodesk, and several of Burry’s Melbourne-based collaborators at the Spatial Information Architecture Laboratory at RMIT use Gehry Technologies’ Digital Project.) Used early on as a time-saver in the process of “reverse engineering,” flexible modeling software later provided an opportunity to experiment iteratively, backtracking and direction-changing with relative ease, and allowed the ready assembly of libraries of parts. The Sagrada Família was also one of the first projects to experiment with rapid prototyping, but it is a combination of digital and physical models, as well as sketches, that inform design even today.

The building materials currently used are in keeping with those selected by Gaudí. They include stone columns and windows (made with granite, basalt, porphyry, and stone from the nearby Montjuïc), vaults of exposed reinforced concrete and flat brick (made using a traditional Catalan technique of superimposed layers of mortared tile and brick), stone roofs, and Venetian-glass mosaics. Steel-reinforced, high-resistance concrete allows some of the larger columns to be built according to Gaudí’s design while meeting current regulations.

The models were traditionally made of gypsum plaster, but more recently have also been mechanically produced using polystyrene or polyurethane. Polyester and fiberglass are also used for making molds. The formwork for the large hyperbolic paraboloids is made of a metal skeleton that is subsequently lined with medium-density-fiberboard paneling. The metal formwork for the smaller paraboloids is covered with a combination of epoxy resins and sand. The skylight hyperboloids are produced with wooden ribs.

Despite 7,000 daily visitors, many of these elements are fabricated on-site and hoisted into position by both traditional methods and specially created machinery. While there are those who are concerned for the safety of visitors, concern for the safety of the building has arisen recently since the Spanish government approved plans to build a high-speed rail line linking Madrid and Barcelona. That line would pass below grade near the church foundations (already flanked by two subway lines). New controversy has since erupted over the already much-debated building.

According to Bonet and his supporters, boring tunnels for the new train would almost certainly wreak havoc on the building; he calls the plan to have a train run so close to its structure irresponsible and reckless. Just this past March, a similar construction project for a metro line in Cologne, Germany, is said to have caused the devastating collapse of the city’s archives building, resulting in the loss of life and irreplaceable historic documents, and generating discussion throughout Europe about such construction projects.

Although the Sagrada Família was included on UNESCO’s list of World Heritage Sites, the World Heritage Committee, which met this summer in Seville, Spain, went against recommendations from the International Council on Monuments and Sites and decided not to place the building on its endangered list, saying it was not in danger of suffering damage from construction of the rail line. Though boring has not started, preliminary work has begun just a mile away from the church as the debate continues in Spanish courts.

While controversies persist, one lingering question remains: Will the building ever be complete? Gaudí used to say that his client “was in no hurry.” In the decades following Gaudí’s death, the running joke was that the Sagrada Família would get finished “in 10 years.” But now there are real dates. For the past several years, construction has been going on in every part of the building, and has reached a point where there does in fact seem to be a light at the end of the tunnel.

Plans call for all interior spaces to be completed and domes sealed by this time next year. The finished, 48,000-square-foot enclosure would make it possible to open the church for worship. But much work is still left to be done. The biggest project yet to be undertaken is the construction of additional towers—taller than existing ones—including an enormous, 550-foot-tall central one (that would exceed in height most high-rise buildings in the city), and the Glory Facade (the last of the three facades). Still, if you ask the current team if the Sagrada Família will ever get finished, their answer is a resounding yes. A potential target date may even be set—2026, the centennial of Gaudí’s death.

No comments: