Treffer: Snow pressure on cableway masts : Analysis of damages and design approach

Cableway masts are often built in slopes exposed to snow pressure. In areas with large snow depths and low ground roughness the creeping and gliding snow cover can exert huge static loads (> 100 kN m-1) on a narrow mast. Three case studies are examined where masts from cableways were completely destroyed by snow pressure forces. The snow pressure equations applied in practical use are explained and illustrated with examples. The equations are based on the snow pressure theory given in the Swiss guidelines for the design of snow supporting structures. The snow pressure depends mainly on the snow depth, snow density, slope angle, gliding factor and efficiency factor. The efficiency factor describes the ratio of the real snow pressure to that on an infinitely long plane. Further, the calculation results are compared with measurements from Norway. To prevent damage the mast can either be designed to the expected snow pressure or the gliding of the snowpack can be prevented by increasing the ground roughness by structural measures e.g. by narrowly spaced poles. Finally, we discuss possibilities for verifying and improving the presented design approach.