Ice Load

1 · Input data

The ice load D_i from freezing rain to ASCE/SEI 7-22 Section 10.4 — the design ice thickness t_d of Equation (10.4-5), the ice area or volume on each member, and the weight of the ice in pounds. Enter each member on the shape that suits it and the page returns the ice load on each member and the total D_i. The nominal ice thickness t is an input, and this page will not invent one. Figures 10.4-2 through 10.4-5 are contour maps carried as raster images: their text layer holds the captions and the Notes and no contour value, so no thickness can be read from this source. Read t, in inches at 33 ft, from the map panel for the structure’s Risk Category, or from the ASCE Atmospheric Ice Geodatabase at the ASCE 7 Hazard Tool, which the maps’ Note 6 permits. The ice density defaults to the 56 pcf floor of 10.4.1 and K_zt to 1.0 for flat terrain; the Risk Category, the map region and a single height for the whole card are optional and may be left blank. This page produces the ice load D_i only: wind acting on the ice-covered structure is Section 10.5, a separate section with its own force coefficients, and it is its own page. A row you leave completely blank is not used; a row with anything in it is a member, and the page refuses it by name if a value it needs is missing. Press Compute D_i when the card is complete.

The members to be loaded

Each row is entered on one of four shapes. Choose the shape first and the geometry cells change what they ask for: a round member takes a circumscribing diameter D_c and a length, a flat plate takes the area of one side A_s, and a dome or a sphere takes a radius r. The orientation — vertical or horizontal — is the 10.4.1 permission to multiply V_i by 0.8 or 0.6, and applies to a plate, a dome or a sphere only; leave it empty to take V_i unreduced, and leave it empty on a round member, which has no V_i to reduce. A cell the chosen shape does not use is labelled “not used for this shape”.

2 · Solution