Opening the Snow/Wind Load dialog and clicking the Permeability tab displays the following dialog.
The dialog lets you define the permeability of a structure wall. Wall permeability has a direct effect on generating internal wind pressure coefficients. When you select an option, its diagram displays in the upper-right corner of the dialog.
The dialog is divided into 3 fields with groups of specific options:
- In Side wall permeability field specifies the left and right side wall permeability. Values for permeability specified in the Left Side and Right Side fields are global permeability values for all members on the left or right side of a structure. Permeability is always expressed in %. For a completely open wall, the permeability value is 100%; whereas, for a completely closed wall, it is 0%.
Robot allows more detailed calculations of permeability on the left or right side of a structure by letting you specify different permeability values for individual members. To do so, select the Advanced option and click Parameters to Parameters of permeability display the dialog.
- In Front and rear wall permeability of field specifies the front and rear wall permeability. Permeability is always expressed in %.
For a completely open wall, the permeability value is 100%; whereas, for a completely closed wall, it is 0%.
- The Door field has the following options:
- Left side - When selected, the door is located on the left-side wall of the building. The permeability value for this wall can be specified in the field on the right.
- Right side - When selected, the door is located on the right-side wall of the building. The permeability value for this wall can be specified in the field on the right.
- Front - When selected, the door is located in the front wall of the building. The permeability value for this side can be specified in the field on the right.
- Rear - When selected, the door is located in the rear wall of the building. The permeability value for this side can be specified in the field on the right.