TOWARDS AN APPROPRIATE FATIGUE LOADING SEQUENCE FOR ROOF CLADDINGS INCYCLONE PRONE AREAS

Currently two different fatigue tests are being used to investigate th e fatigue susceptibility of roof claddings in the cyclone prone areas of Australia. In order to resolve this issue a detailed investigation was conducted to study the nature of cyclonic wind forces using wind t unnel testing and computer modelling and the fatigue behaviour of meta l roof claddings using structural testing. This led to the development of an accurate, but complicated loading matrix for a design cyclone. Based on this matrix, a simplified low-high-low loading sequence has b een developed for the testing of roofing systems in cyclone prone area s. This paper first reviews the currently used fatigue loading sequenc es, then presents details of the cyclonic wind loading matrix and fina lly the development of the new simplified loading sequence. This simpl ified sequence should become the only suitable test for most of the cy clone prone areas of Australia covered by Region C which suffers from Category 4 cyclones. For Region D which suffers from Category 5 cyclon es, the same loading sequence with 20% increased cycles has been recom mended. An experimental programme to validate the new simplified loadi ng sequence has been proposed.