STAAD.Pro Help

M. To add a GB50009 wind load definition

To add a wind load definition and load cases for the Chinese GB50009-2012 code, use the following procedure.

These steps are performed when adding a wind load definition in the Add New: Wind Definitions dialog.

This procedure is used to generate a series of wind intensity vs. height values based on the procedure of the GB 50009-2012 code.

  1. In the Load & Definition dialog, select the Definitions > Wind Load entry and then click Add. The Add new: Wind Definition dialog opens.
  2. Select GB 50009-2012 from the Code drop-down list.
  3. Click Add. The definition type is added to the Definitions > Wind Load entry in the Load & Definition dialog.
  4. In the Load & Definition dialog, select the new wind definition type and click the Add. The Add New: Wind Definitions dialog opens. The dialog now displays the Intensity and Exposures tabs.
    Note: The previously selected Code displays as a read-only selection.
  5. Click Generate. The Generate Wind Definition and Wind Load Case for Chinese GB 50009 dialog opens.
  6. Enter the parameters to calculate the height variation factor for the wind pressure, μz:
    1. Type the Building Height and Bottom Elevation
    2. Select the method to sub-divide the height above ground into discreet points of the wind intensity curve.
      • Segment Count to Divide Height (H) Equally - This is the segment count to divide equally the total height (H) of the current building. This is used to calculate the individual height (z) where the wind pressure needs to be calculated.
      • Equal Segment Length Along Height (H) - This is the segment length, and the length is equal. The length is along the total height (H) of the current building. This is used to calculate the individual height (z) where the wind pressure needs to be calculated.
      • Provide Special Height (z) - This is the special height (z) list. This is the individual height (z) where the wind pressure needs to be calculated. The delimiter for the individual height (z) can be comma (,) or space, such as 3,6,9.
    3. Select the Roughness Type.
    4. (Optional) Type a Modification Factor.
  7. Select the options used to calculate the wind shape factor, μs:
    1. Select the Shape Item ID from the drop-down list:
      • 30 : Closed Polygon Building
      • 37 : Circular Section Structure (Chimney)
    2. For closed polygon buildings, select the Secondary Shape Type from the drop-down list.
    3. Click Set Shape Factor to specify shape factor parameters in the Set Shape Factor dialog.

      For closed polygon buildings, refer to the dialog diagrams for definitions of the faces. For circular structures, select the change in diameter and specify the diameter values accordingly.

    4. Type shape factor values for each structure face and wind direction.
    5. Click OK.
    6. (Optional) Type the Interference Factor from Other Building value if appropriate.
  8. Specify the values for the reference wind pressure, w0:
    1. Type the Reference Wind Pressure value.
    2. (Optional) Type a Modification Factor value to use if appropriate.
  9. (Optional) If the wind-induced vibration factor, βz, along-wind is to be considered, do the following:
    1. Check the Consider Along-wind Vibration Factor option.
    2. Type the Damping Ratio to use. This should be greater than zero.
    3. Type the Basic Natural Vibration Period (T1) of the building.
    4. Select the appropriate Structure Type:
      • High-rise Building - The structure type of the current building is high-rise building. The high-rise building is the modern building which is very tall and has many levels or floors. The width of the windward face of the high-rise building is larger than that of the high-tower structure.
      • High-tower Structure - The structure type of the current structure is high-tower structure. The width of the windward face of the high-tower structure is far less than its height, and is also less than that of the high-rise building.
    5. Click Provide Width of Windward Face to specify the windward face dimensions based on the Structure Type selected.
  10. Generate wind load cases for the load definition automatically:
    1. Select the Wind Load Case tab.
    2. Check the Generate Wind Load Case option.
    3. Enter the range values in each of the global axis directions to specify the range of the wind load.
    4. If the structure is open, then check the Open option.
  11. Click OK. The Intensity vs. Height table is populated with the calculated values.
  12. Click Add. The wind definition and generated load cases are added to the model.
A series of four load cases are generated (one for each structure face), each with four load items for each of the four wind directions.
The wind load generation data is stored within the STAAD input file. Therefore, you can use the same procedure to modify the wind load generation to update the wind definition and load cases.