Four Sports Halls by Giancarlo Mazzanti and Felipe Mesa, Plan:B, Medellín, Colombia

There is a pleasing symmetry in the plan that complements the Iván de Bedout football stadium with four new sports halls, across the street from the four new pools of the Aquatic Centre. These two ambitious projects fill out the expansive diamond of the Atanasio Giradot sports complex, and all were completed in time to host the 2010 South American Games. Like the pools, the halls have remained in constant use by schools and local leagues, and are open to the public for all but ticketed events. Their fretted metal sides allow everyone to glimpse a game for free, blurring the boundary between spectacle and circulation. Visual and physical permeability is a key element of the design.

Giancarlo Mazzanti, who is based in Bogotá, collaborated closely with Felipe Mesa of Plan:b in Medellín on the competition-winning entry, which combined speed and economy of construction with a response to the mountains that frame the Aburrá Valley. Decrepit structures were removed from the site, leaving only the concrete bleachers of the basketball court, seating 2,500 on two sides. This is the largest of the quartet, but it is fully integrated with the halls for volleyball and martial arts, each seating 1,600, and the 800-seat gymnastics hall.

They are independent units, but the roof vaults are extended to shelter the spaces between, so that they read from above or afar as a unified structure. The shadow these roofs cast on a sunny day further expands the composition, balancing the mass of the stadium.

The roofs that give the complex its distinctive profile were conceived for ease of manufacture and assembly. Lattice steel trusses were brought to the site in 12m lengths, bolted together and craned into place. They are set at 5m intervals and are supported at either end by double columns fabricated from reinforced concrete.

Roofs are oriented north-south to exclude direct sun and high-level slots at either end draw in fresh air for cross ventilation. Natural light is filtered through the opalescent polycarbonate panels beneath each arch and banks of lighting for nighttime events are contained within the beams. Well-insulated bands of composition board are wrapped over the arched trusses, and seven prefabricated shapes are used in different configurations to suggest a greater complexity of form.

For Mazzanti, the alternating strips evolved out of his unrealized proposals for the Spanish Cultural Centre in Bogotá and the Nevado del Ruiz refuge. And the rational construction that allowed the complex to be built in only 12 months draws on his experience in modular school building.

Both architects insist that the design was a joint effort, a meeting of minds on concept and form. Along with the Mazzanti’s Biblioteca de España, and the Orquideorama, on which Mesa worked with J. Paul and Camilo Restrepo, the sports halls are an inspired fusion of function and poetry. The undulating profile of the roof bands, coated in several shades of green, evokes the canopy of a rain forest as much as the mountains on the skyline. That impression of a man-made grove is heightened by the play of light through the perforated walls and the slender branching steel columns that support the extended roof plane.

Within each space, the structural skeleton is a metaphor for taut muscles and graceful leaps, and the volume it defines is equally dynamic.