EN 1991-1-3 NF Snow loads family

 

The EN 1991-1-3 NF Snow loads family is created when the Eurocodes 1 (EC1) - France climatic standard is selected for the current project.

EN 1991-1-3 NF Snow loads family - Properties

Family

• Name: the default name of the family.

• No.: displays the ID number of the family.

Snow category

• Category: allows the selection of the snow region type. When selecting user-defined, is possible to define custom values for the combination coefficients.

Combinations

Define properties that are taken into account when generating concomitance combinations. See Configuring load cases combinations.

• Group loads: when enabled, each load case inherits "combinations" properties from the corresponding load case family and will be grouped as a generic load case in the concomitance matrix.

• Effect: sets the load case as "Leading", "Accompanying" or both.

• Coefficient γ EQU: partial factor for wind action considered in the EQU ultimate limit state (according to table A1.2 (A) from EN 1990)

• Coefficient γ STR/GEO: partial factor for wind action considered in the STR/GEO ultimate limit state (according to table A1.2 (B) from EN 1990)

• Ψ0 coefficient: factor that defines the combination value of a variable action (see clause A1.2.2 and table A1.1 from National Annex of NF EN 1990)

• Ψ1 coefficient: factor that defines the frequent value of a variable action (see clause A1.2.2 and table A1.1 from National Annex of NF EN 1990)

• Ψ2 coefficient: factor that defines the quasi-permanent value of a variable action (see clause A1.2.2 and table A1.1 from National Annex of NF EN 1990)

Color

• View / change the representative color for the family.

Situation of the project

• Exceptional snow accumulation: enables/disables the snow accumulation option.

• Exceptional snow fall: enables/disables the exceptional snow.

• No accumulation on NS and AS: if enabled, the undrifted snow arrangement (or uniform snow or case (I)) will not feature any snow accumulation. The accumulations on parapet walls will only be featured in the drifted snow arrangements (cases (II) and (III)).

Parameters

• Typical value: defines the snow region. Each region is defined by certain snow loads values. To set custom values for the snow loads, select Other.

• The button displays the snow regions map and allows the selection of the corresponding region.

Regions for EN 1991-1-3 NF snow loads family

• Snow load: automatically calculated according to the selected region. A custom value (in kN/m2) can also be set.

• Exceptional snow load: automatically calculated according to the selected region. A custom value (in kN/m2) can also be set.

• Exposure factor: allows the selection of the location type: swept by the winds, normal or protected.

• Thermal factor: the thermal coefficient (Ct) varies in special cases (when the roofs have high thermal transmittance ( > 1 W/ m2 K ), in particular for some glass covered roofs, because of melting caused by heat loss). In all other cases, Ct = 1.00.

• Altitude: allows the definition of the location altitude.

Tip

Click a section of the properties window. Notice the bottom area of the window; it displays a short description of the active cell's content.

 

Accessing the properties

After creating a snow load case family: in the Project Browser, expand the Loading group and select Snow EN 1991-1-3 NF.