| 摘要 |
Method for designing a corrugated roofing sheet (1) made of natural fibres, notably cellulose fibres, impregnated with bitumen comprising a uniform pattern of mutually parallel alternating corrugations borne by a mid-plane (4), said corrugations defining rounded crests (2) each separated from the next by a rounded trough (3), the crests and trough being connected by alternately inclined portions (5, 5'), the transverse offset between two successive crests (2) being equal to the transverse offset between two successive troughs (3) and defining the pitch P of the corrugations, the sheet (1) having a thickness E of material substantially constant over its extent, the sheet having a height H defined as being twice the distance between the mid-plane (4) and the exterior surface of a crest (2) or twice the distance between the mid-plane (4) and the exterior surface of a trough (3), these two distances being identical. The height H, thickness E and pitch P values for the sheet are determined by solving the inequation Fi < H3/(8 x E x (H + P)) < Fs where Fi = 25 mm and Fs = 35 mm. A sheet with dimensions H, P, E corresponding to the inequation is also considered. |
