Snow/Wind Loads

Snow/wind loads can be generated by

• Clicking the Loads menu > Wind & Snow > Wind and Snow 2D/3D.
• Clicking .

Note: The Snow/Window Loads option is available only for plane frame and plane truss structures. You can generate snow/wind loads for 3D frames and 3D trusses. This option is unavailable if you have not defined a structure.

The Snow/Wind Load dialog has conditions for which snow/wind loads are generated:

• Envelope - Defines those structure elements for which snow and wind loads will be generated. The numbers of the selected nodes create the envelope. It is a required parameter for defining global snow and wind coefficients of a structure.
  Note: To correctly generate snow and wind loads this option must be specified.

  To select an envelope:

  1. Enter the numbers for consecutive nodes.
  2. Highlight the nodes in the drawing area.
  3. When defining the envelope manually, you can create either an open or closed envelope (depending on whether you go back to the first node.)
• Auto - Begins generating the automatic envelope. Parameters are set according to the selected options for automatic envelope recognition.
• Without Parapets - When selected, an envelope is generated automatically without regard to parapets.
• Without Cavities - When selected, an envelope is generated automatically without regard to cavities. Fictitious envelope elements are created instead.
• With Base Not on the Ground - When selected, an envelope is generated automatically without regard to a base on the ground; therefore, letting you create an envelope for aerodynamically insulated structures.
• Isolated roofs - If this option is selected, the structure is an isolated roof and loads are generated only on the isolated roof.

To define snow/wind loads, you must specify basic parameters for the structure:

• Total depth - Defines the building depth (length). It is a required parameter for defining global snow and wind coefficients of a structure.
  Note: To correctly generate snow and wind loads this option must be specified.
• Bay spacing - Defines the bearing element spacing on a structure length. It is a required parameter that accounts for the accumulation of loads from the appropriate side walls.
  Note: To correctly generate snow and wind loads this option must be specified.

At the bottom of the dialog, there are the following 2 options:

• Wind - When selected, creates wind load cases during the generation of snow/wind loads; when cleared, prevents Robot from creating wind load cases.
• Snow - When selected, creates snow load cases during the generation of snow/wind loads; when cleared, prevents Robot from creating snow load cases.

At the bottom of the dialog is the Display note after load generation option. When selected, Robot runs the text editor that displays the load values it calculated for individual snow and wind load cases. When cleared, Robot saves the files containing the calculation notes for the snow and wind loads cases to the local user folder \Users\...\Documents\Autodesk\Output.

Clicking Parameters opens the dialog for setting detailed parameters for snow and wind loads.

Note: This button is inactive until an envelope, building spacing, and depth are specified.