Recent Developments in the Australian/New Zealand Standard AS/NZS 4600 for Cold-Formed Steel Structures

摘要

The Australian/New Zealand Standard AS/NZS 4600 is currently under revision based in part on the latest edition of the North American Specification AISI S100:2012 and partly based on the latest research in Australia and New Zealand. The Direct Strength Method (DSM) of design has undergone substantial research since the 2005 edition of AS/NZS 4600 and this research is now incorporated in the revised edition. The new areas in the DSM include shear, combined bending and shear, combined bending and compression, sections with holes and inelastic reserve capacity. Further, the prequalified sections now include most sections with longitudinal web and flange stiffeners based in part on Australian research on high strength sections with multiple stiffeners. New areas in the Australian/New Zealand Standard include extension of Section 8 Testing to design based on testing, Section 9 Design for Fire, Appendix B Methods of Analysis including advanced analysis, and Appendix D Buckling moments and stresses for local, distortional and global buckling. Revisions of design rules for net section tension and block shear rupture at bolted connections based on Australian research, inclusion of oversize and slotted holes, and screwed connections in tension and shear now are also included. The paper includes the research basis of the latest revisions with the supporting references. The Australian Buildings Code Board (ABCB), which regulates buildings in Australia by way of the National Construction Code (NCC 2015), has recently changed the loading data for wind, snow and earthquake from 50 year to annual probability of occurrence. This has the effect of increasing the target safety indices. The paper describes the recalibration process for test based design "using the revised loading data.