Monday, April 07, 2014

Wind Loading BCA Importance Levels

A simple spreadsheet that maps Building Code of Australia (BCA) importance levels against the annual probabilities of exceedance (actually mean return periods). Excel trend line facilities are then used to get a formula so that any mean return period can be mapped to an importance level.

Whilst AS1170.2 allows for any mean return period, the BCA has limitations, which are not always suitable, starting with the fact that the BCA is primarily about habitable buildings and anything which is not a habitable building becomes BCA class 10. However the BCA is not suitable for design of any structure classified as class 10. For example a garden shed or carport may be suitable to be designed to BCA volume 2, but a 600m high radio mast is not.

Additionally importance level 2, with mean return period (R) of 500 years is not suitable for all buildings, and then again an importance level of 1 (R=100 years) is not always suitable, therefore helpful to identify alternative importance levels: to show that have importance between 1 and 2.  For those who prefer importance levels.

The spreadsheet can be downloaded here. bcaImportanceLevels.xls

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