Basic Wind Data (ASCE 7 Wind Wizard)

Tekla Structural Designer
2021
Tekla Structural Designer

Basic Wind Data (ASCE 7 Wind Wizard)

Once the geometry has been confirmed, (for either method), you are then required to enter the basic wind data. The only difference between the two methods is that the Gust Effect Factor field is only shown for the All Heights Method.

Property/Buttons Description
Property
Basic Wind Speed (Clause 26.5.1) A strictly positive value is required with 90mph being the default.
Hurricane-Prone Region (Clause 26.2) The default is cleared, i.e. region not prone to hurricanes.
Directionality Factor, Kd (Clause 26.6, and Table 26.6-1) The default is 0.85, range 0.85 to 1.0 inclusive.
Note: There is no cross-checking to ensure that the model has met the load combination criteria. If that does not apply, then it is your own responsibility to enter the correct value of 1.0.
Enclosure Classification (Clause 26.10) Options are "Enclosed" and "Partially Enclosed" with default being "Enclosed".
Note: "Open" structures are not handled in the current version of the program
Gust Effect Factor (Clause 26.9.1) This will only be shown for the All Heights Method. The default value is 0.85.
Principal Axes There are always four directions shown for principal axes, being based on the Orientation of the Longitudinal Direction or Principal Axes depending on the method. You are not able to add, delete or modify any direction.
Exposure Category (Clause 26.7.3) Options are "B", "C" or "D" with default being "B".
Topographic Feature (Clause 26.8 and Figure 26.8-1)

Options are as follows, with the default being "None":

  • "None" - no feature, i.e. Kzt = 1.0.

  • "2D Ridge"

  • "2D Escarp" - 2D Escarpment

  • "3D Hill" - 3D Axisymmetrical Hill

Crest Height, H (Figure 26.8-1)

Height of the hill or escarpment relative to the upwind terrain.

The behaviour of this field depends on the Feature type as follows:

  • "2D Ridge" - non-zero values allowed, (negative indicates a valley).

  • "2D Escarp" - strictly positive values allowed

  • "3D Hill" - strictly positive values allowed

Crest Length, Lh (Figure 26.8-1) Distance upwind of crest to where the difference in ground elevation is half the height of the hill or escarpment.
Distance to Crest, x (Figure 26.8-1)

Distance upwind or downwind from the crest to the building site.

The value may be positive to indicate downwind, or negative to indicate upwind.

Buttons
Next Clicking Next takes you to the Results page.
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