User documentation
This calculation is presented in three layouts – Full, Standard and Brief
Dialogue
National annex selector
Combobox "National Annex" is used for selecting proper annex for calculation of the snow load.
Snow load requires selecion the national annex, because in Standard EN are not defined characteristic values of snow load on the ground.
For explanation of the National annex parameters related to snow load select national annex from the list below.
General properties
General properties are similar to all snow load forms.
Checkbox "Print headline" represent official name for calculation. User can change it by uncheck "Print headline" and check "Print userdefined headline" and write his own headline into appropriate string line.
Checkbox "Print the geometry of the roof" show/hide block with Dimensions of the construction
Checkbox "Print the calculation of the load at unit lenght of the roof" show/hide calculation of the Load at unit length in the direction of roof
Checkbox "Undrifted snow" show/hide the calculation of undrifted load case (i)
Checkbox "Drifted snow" show/hide the calculation of drifted load case (ii)
Geometry of the roof
Height from the eaves to the ridge is in meters. Limits are from 0 to 50 m.
Width of the roof arch is in meters. Limits are from 0 to 100 m.
Loaded width of the roof where β <= 60° is in meters. Limits are from 0 to 100 m.
For British and Irish national code is necessary to define also Angle between horizontal and the tangent to the roof at the eaves in degrees. Limits are from 0° to 90°.
Parameters of the snow load
These parameters are depended on selected National annex.
Exposure coefficient
These parameters are depended on selected National annex.
Thermal coefficient
These parameters are depended on selected National annex.
Calculation
Dimensions of the construction
Values in this block are defined in the dialog. This block can be hidden by checkbox "Print the geometry of the roof".
Characteristic value of snow load on the ground and Coefficients
These parts of calculation are described in the annotation for Coefficients for the snow load
Calculation of snow load - Case (i) - Undrifted snow
Calculation of undrifted snow is independent on selected national annex.
s = μ3,1 • Ce • Ct • sk
S = s • ls
Calculation of snow load - Case (ii) - Drifted snow
Calculation of drifted snow is dependent on selected national annex.
Standard calculation is described.
s1 = 0,5 • μ3,1 • Ce • Ct • sk
s2 = μ3,1 • Ce • Ct • sk
S = (s1 • ls) / 4 + (s2 • ls) / 4
Explanation of symbols
b - Width of the roof arch [m]
h - Height from the eaves to the ridge [m]
ls - Loaded width of the roof where β <= 60° [m]
s - Snow load at the unit area [kN/m2]
sk - Characteristic value of snow load on the ground [kN/m2]
S - Snow load at unit lenght of the roof [kN/m]
μ3,1 - Shape coefficient