ANALYSIS AND DESIGN OF SNOWSHEDS

Abstract

In snow bound areas, occurrence of avalanches is a common phenomenon. It causes not only disruption of traffic but also loss in terms of life and property. Snowshed is a structure to protect the roads and railways at points where they cross, defined avalanche paths. The snowsheds covering the full width of broad highways are very expensive. In the present study, to understand the avalanches in a closer detail, a general description is given. Avalanches are generally a part of valley glaciers which get detached from the main body under certain circumstances and roll down with considerable momentum along the steep slopes of mountains. The destructive effect of avalanches is the result of their kinetic energy, which depends on the specific gravity, of snow and of the speed of the avalanches. The snowshed is analysed for two cases (i) Columns not supporting retaining wall (ii) Retaining wall in built with the columns. For both cases the depth of snow on the snowshed is assumed as 9.0m and the frictional load due to avalanche is assumed as 23.5 kN/m2. For the first case, various curves have been drawn for different members of snowshed. These curve can be directly used to find out different forces including axial, shear and moment for a given span and spacing. For the analysis of snowshed, a computer program is prepared. Besides this, the analysis and the design of different members of snowshed, for the case of columns supporting retaining wall, is carried out and it has been found that the requirement of steel is very high.