Canopy for Stade Elisabeth, Paris

Against the backdrop of a large red-and-black mosaic, the architect has drawn a wavy line on a series of thin legs to create a shelter above an existing 50 m long rostrum. The drawing is simple: a 15 mm steel sheet and 45 round steel supports, 55 mm in diameter, are arranged more or less at random on the three steps of the rostrum. The curve was optimised to prevent spread forces in the roof plate from causing buckling and the ten five-metre sections of sheet steel were bent in the workshop and invisibly joined on site using countersunk bolts in overlapping half-thickness edges. The columns have to support the top both vertically and horizontally. Because the 15 columns in the front row are located approximately in the middle of the 5 m wide canopy, they bear almost all the weight. By contrast, the columns in the back rows, which carry only a small proportion of the weight, react most rigidly to the horizontal loads and thus perform a bracing function.