For the 1988 Swiss Building Fair, staged in Basel over a period of six days, the Swiss Association of Manufacturers of Precast Cement Elements commissioned Calatrava to develop an innovative structure that would demonstrate modern concrete casting technology at the experimental level.
Calatrava set the normally rigid, static material in motion, to challenge the fixed spatial image of concrete as construction. Calatrava's concept was also intended to present a challenge to the manufacturers by exploring the engineering problems associated with casting high-strength, dynamically loaded concrete, using oiled, linoleum-lined compound-curve precision formwork. To achieve a very compact, fine-grained, silk-like finish, careful consideration of steel reinforcement and meticulous temperature control of the curing process were required.
Each of the 14 individually cast elements of this articulated 'rib-cage' were 7.8 meters long. They varied between 10 and 52 centimeters in width and weighed 1.2 tons. Balanced on trunnions that rested on concrete brackets cantilevered 1.86 meters out from the rear support wall, these graceful aerodynamic ribs were connected at their innermost ends via a series of cranks to a row of excentric pins, which in turn were connected at progressively staggered angles to an endless chain. This drive configuration imparted a cyclic wave motion to the slender tips extending above the floor. In this case, Calatrava investigated a mobile structure that could be experienced spatially: the periodic motion of the roof imparted a rolling, volumetric change to the space below. This kinetic use of a slender yet heavy concrete form proved to be highly successful. Although the motion was slow, the material was fully able to withstand the inherent flexing of the design, and the fine finish was durable. Indeed, the structure has since been moved to an outside site and shows little sign of weathering.
1989 - 1989