Wind Loading Surface Roughness Length versus Terrain Category

A simple spreadsheet making use of AS1170.2:1989 Appendix E. This appendix provided formula for converting surface roughness length (z0) into terrain category and for region A the calculation of the terrain adjusted wind speed or otherwise the terrain category multiplier (Mz,cat).

AS1170.2 commentary contains a design chart which identifies various terrains and gives the surface roughness length (z0). From this chart it is apparent that most rural properties are not TC3 but also they are not TC2. By the use of z0 an intermediate terrain category can be calculated and more economical designs are possible.

The spreadsheet can be downloaded here: surfaceRoughnessLength.xls

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Revisions:
[07/04/2014] Original
[23/04/2016] Changed download links to MiScion Pty Ltd Web Store