Let us return to the first architecture class on structures and the classification of structural efforts. In most structures, whether natural or man-made, compression forces are the primary actors. These are efforts undertaken with equal and opposing loads, applied in the interior of the structure, which tend towards the shortening of the piece in one direction - or compressing it, as the name indicates. It is not difficult to find examples of this: for example, a stone wall or a wooden log can resist the weight of a covering through internal compression efforts that are inherent to each material. Tension efforts, on the other hand, tend to lengthen components in the direction of the applied force of action. Steel, for example, is a material with good tensile strength. It is used in reinforced concrete precisely in the parts where the piece is in traction. But it is also possible for a structure to only have tensile parts, as is the case of membrane, tensioned, or tension structures, which consist of surfaces pulled by the action of cables or ropes in which the masts absorb compression efforts.
Frei Otto
The Architectural Lab: A History Of World Expos
World Expos have long been important in advancing architectural innovation and discourse. Many of our most beloved monuments were designed and constructed specifically for world’s fairs, only to remain as iconic fixtures in the cities that host them. But what is it about Expos that seem to create such lasting architectural landmarks, and is this still the case today? Throughout history, each new Expo offered architects an opportunity to present radical ideas and use these events as a creative laboratory for testing bold innovations in design and building technology. World’s fairs inevitably encourage competition, with every country striving to put their best foot forward at almost any cost. This carte blanche of sorts allows architects to eschew many of the programmatic constraints of everyday commissions and concentrate on expressing ideas in their purest form. Many masterworks such as Mies van der Rohe’s German Pavilion (better known as the Barcelona Pavilion) for the 1929 Barcelona International Exposition are so wholeheartedly devoted to their conceptual approach that they could only be possible in the context of an Exposition pavilion.
To celebrate the opening of Expo Milano 2015 tomorrow, we’ve rounded up a few of history’s most noteworthy World Expositions to take a closer look at their impact on architectural development.
AD Classics: German Pavilion, Expo '67 / Frei Otto and Rolf Gutbrod
The pivotal turning point in the late Frei Otto’s career – capped by last month’s Pritzker announcement – came nearly fifty years ago at the Expo ’67 World’s Fair in Montreal, Quebec. In collaboration with architect Rolf Gutbrod, Otto was responsible for the exhibition pavilion of the Federal Republic of Germany, a tensile canopy structure that brought his experiments in lightweight architecture to the international stage for the first time. Together with Fuller’s Biosphere and Safdie’s Habitat 67, the German Pavilion was part of the Expo’s late-modern demonstration of the potential of technology, pre-fabrication, and mass production to generate a new humanitarian direction for architecture. This remarkable collection at the Expo was both the zenith of modern meliorism and its tragic swan song; never since has the world seen such a singularly hopeful display of innovative architecture.