Estadio Ciudad de la Plata, Buenos Aires, Argentina

The Outstanding Structure Award Committee, chaired by William J. Nugent, USA, presents the Outstanding Structure Award 2012 to the: Estadio Ciudad de la Plata, Buenos Aires, Argentina; ‘a quintessence of innovation,this 53 000-seat stadium features a striking, twin-peaked, Teflon-covered roof structure comprised of a one-of-akind spatial network of pre-stressed steel cables and lightweight steel columns’. The Award will be officially presented in Buenos Aires at a Plaque Presentation Ceremony.

Weidlinger Associates, Inc., designed the stadium with architect Roberto Ferreira and Associates, Barcelona, Spain, in the late 1990s; however when Argentina’s economy faltered, it was only partially constructed. The La Plata football stadium opened in 2003 with its essentials only - a natural grass playing field and seating bowl - and lacking its signature twin-peaked dome. In 2001, when construction was interrupted, the triangular steel truss perimeter compression ring had already been completed and placed atop the seating berm, and materials that had been purchased for the dome were stored, awaiting a resurgence of the Argentine economy. In 2009, with the notification that Argentina had been chosen to host the 2011 Copa América, construction was resumed.
 
Originality and Innovation
La Plata Stadium is the first polytetrafluoroethylene (PTFE, commonly known as ‘Teflon’) covered stadium in South America and the first designed to use a fabric with a 24 % translucency. Its design is based on the concept developed by architect Roberto Ferreira, which employs a unique dogbone configuration to provide separate identities for the two football teams that reside there. In plan, the two intersecting circles have 85 m radii, but their centres are only 48 m apart. An arch resists the structure’s outward thrust across its pinched-waist centreline. The dome’s patented Twinstar design is the first anywhere to adapt the tensegrity roof concept to a twin-peak contour. It forms a figure-eight-shaped central opening by using tension to resist global distortion. To accommodate the unconventional geometry of the stadium, the main roof structure was formed using tensioned steel cable hoops at three levels, along with vertical columns, diagonal cables, and ridge cables. It is defined as a ‘spatial network in a state of self-stress’. The system works like a truss in which the bottom chord is interrupted and then follows the line of hoop cables around to the opposite side of the arena. As a truly three-dimensional system, it benefits from the triangularisation of structural elements, which improves its load-carrying capability and permits unconventional geometry.

Sustainability Considerations
La Plata’s dome is constructed of extremely durable fabric and steel. The PTFE-fibreglass membrane it is clad in allows sufficient sunlight to nourish the stadium’s natural grass playing field. The fabric is capable of withstanding temperatures from −100°F (−75°C) to 450°F (232°C) and is flame-resistant, waterproof, and impervious to ultraviolet rays. All steel elements were fabricated locally. The durability and relatively low cost of the fabric make it an extremely economical construction material. The roof is open along the perimeter to allow air to circulate naturally without forced ventilation in the final configuration of the roof, which will be closed.