Rigid Buildings of All Heights - Geometry (ASCE 7 Wind Wizard)
The following geometry items are required for this method. You can override calculated dimensions using your engineering judgement.
| Property/Buttons | Description |
|---|---|
| Property | |
| Ground Level in Model (Ignore Wind Below) | If for some reason, the level 0.0 feet in the Tekla Structural Designer model does not correspond to the ground level, for example you have used a site datum rather than a building datum, then this field allows you to set the appropriate value so that the reference heights for the wind can be calculated correctly. The default is zero. The allowed maximum is the minimum wall or roof height. Changing the value in this field will cause the Mean Roof Height to be recalculated, unless you have chosen to override that dimension. |
| Orientation of Principal Axes |
This is similar to the Orientation of Longitudinal Direction relative to axes (Figure 28.4-1) for Low-Rise Buildings. Although there is no need to distinguish between the Longitudinal and Transverse axes for this method, the wind X axis will be aligned to this direction with the Y axis at right angles. The vortex view will be slightly different to the Low-Rise one to reflect that. Due to the potential complexity of the model, the Wind Wizard... will only attempt to determine the correct angle for the axes if the building is also suitable for Low Rise, otherwise zero is used as the default. |
| Mean Roof Height, h (Clause 26.2) |
For this method, the actual reference height is only be used for the pressure on windward walls. For all other walls, and roofs, a single height is used to determine the pressure for each direction. By default, the height is calculated as for Low-Rise Buildings except that there is no single value of θ, so the eaves height is only used if all the roof angles are <= 10°. You are able to override the calculated value by checking the box. |
| Level of Highest Opening in Building, zi (Clause 27.4.1) | For this method, qi is evaluated at height h for all cases except for positive internal pressure in partially enclosed buildings, where it should be evaluated at the level of the highest opening. However, the clause allows h to be used even for this case, so the default is for the box to be checked and the level to be automatically updated as the Mean Roof Height changes. |
| Overall Building X Dimension and Overall Building Y Dimension (Clause 26.3) |
These dimensions are calculated from the smallest enclosing rectangle (considered over all roof and walls only), relative to the given orientation of the Principal Axes - see figure below. You are able to override each calculated value by checking its box. These values will then be used to derive the L and B dimensions for each wind direction. For X Axis, L = X Dimension, B = Y Dimension. For Y Axis, L = Y Dimension, B = X Dimension:
|
| Design Pressure Factor (Figure 27.4.8 and Clause 27.4.6) | This defaults to 75%, but the commentary suggests that this may not cover all cases so you are allowed to change it. A single factor is used for all Torsional loadcases. |
| Eccentricity (Figure 27.4.8 and Clause 27.4.6) | This defaults to 15% but again, the commentary suggests that this may not cover all cases so you are allowed to change it. A single factor is used for all Torsional loadcases. |
| Buttons | |
| Next | Clicking Next takes you to the Basic wind data page. |
