In a conversation which took place with Juan María Songel (GG Barcelona, 2008 p 91) Frei Otto regrets that the Olympic stadium roof could not be lighter, owing to the necessity to adapt it to a form previously designed by the winner of the competition, the architect Günter Benisch.
The engineer's desire was to achieve minimum impact on the park, like a veil laid over the hill. For the first time in his experimentation with cable mesh nets, the form was not generated by natural physical processes, but by a preconceived design.
Photos taken by a+t, available under request.
Frei Otto, Günther Benisch
The roof is suspended from 12 articulated steel masts of varying heights
The roof has a surface area of 74,800m2
A network of rectangular mesh pre-stressed cables, spaced at 75cm in both directions and with a varying intersection angle enabling them to be accommodated to the curvatures of the roof
The roof covering consists of a 2.9 x 29 m, 4 mm thick sheet of PVC-coated polyester fabric. To avoid deformation caused by temperature change, it rests on neoprene pedestals
Given the lack of previous experience working with these dimensions, the authors made an initial 1:125 scale model. Later workshop drawings were made of the whole roofing surface on 1:10, thanks to a computer program developed for the occasion
The original capacity was for 80,0000 spectators, later reduced to 69,000