Length over which the end-effect loads impinge (measured along the contour line)

Пояснение:

With finite width of the supporting surface in the contour line, incremental end-effect loads occur by virtue of the fact that the snow can flow laterally around the surface, so that a lateral restraining effect occurs. The end-effect loads are dependent not only on the factors determining the snow pressure on an infinitely wide surface, but also on the dimensions, shape and surface roughness of the grate, and even more so on the glide factor. The basic snow pressure distribution is shown in Fig. 17. For practical calculations, the end-effect force is substituted by an equivalent, constant, force per meter run S'R acting over the length Д1 (see Section 5.5.2.4).

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Указания по расчету снеголавинных нагрузок при проектировании сооружений, ВСН 02-73 Вам в помощь.