Limitations (ASCE 7 Wind Wizard)
Throughout the development of the Wind Wizard extensive reference has been made to these references and we consider it advisable that you are fully familiar with these before using the software.
In addition, because wind loading is complex and its application to general structures even more so, it is essential that you read and fully appreciate the following limitations in the software:
Note: Unless explicitly noted otherwise,
all clauses, figures and tables referred to are taken from ASCE 7-10. Ref 1
Geometry
The shape of the building must lie within the shapes that are valid according to ASCE 7-10 Clauses 27.1.2 and 28.1.2:
- It should be a regular shaped building or structure
- It should not have response characteristics making it subject to across-wind loading, vortex shedding, instability due to galloping or flutter; or have a site location for which channeling effects or buffeting in the wake of upwind obstructions warrant special consideration.
Although the software will generate wind loads for many situations - it is up to you to accept that the loads generated are suitable according to ASCE 7-10.
Other documented limitations include:
- Buildings must be enclosed or partially enclosed.
- Open sided buildings are not considered.
- Only rigid buildings are considered, not flexible buildings.
- Zones and loadcases are not generated for components and cladding.
- You will need to establish and enter the wind data yourself.
- Roof types must be set manually.
- Barrel-vault and domed roofs are not considered.
- Parapets and free-standing canopies are not considered.
- Roof Overhangs are not explicitly handled.
- There is no special handling for Multi-Bay roofs as they are not covered explicitly in ASCE 7-10.
- There is no special handling for troughed roofs as they are not covered explicitly in ASCE 7-10.
Loaded area
The difference between the loaded area of wall panels and roof panels defined at the centre-line rather than the sheeting dimension is ignored.
Wind direction
- All outward faces within 60 degs of being perpendicular to wind direction - loads applied as windward normal to face. All inside faces within 60 degs to wind direction - loads applied as leeward normal to face. All other faces considered as side.
- Orthogonal wind directions at the definition of the user.
Design wind load
The design wind load is not explicitly checked to ensure it is greater than the minimum of 16 psf - (as per Clause 27.4.7 for the Directional method, or 28.4.4 for the Envelope procedure.)
However, the average wind pressure for each of Windward, Leeward and Side directions is provided for you to manually check this is satisfied.
Additional wind loads
There may be situations when you perceive a need to manually define loads that cannot be determined automatically. You can do this by defining additional wind loadcases to contain these loads and then include these with the relevant system generated loads in design combinations in the normal way.