Ninth International Conference on Advances in Steel Structures (ICASS’2018) 5-7 December 2018 - Hong Kong, China Proceedings of the ninth international conference on Advances in Steel Structures Edited by Siu-Lai Chan, Tak-Ming Chan and Songye Zhu. Copyright © 2018 by The Hong Kong Institute of Steel Construction. EXPERIMENTAL INVESTIGATION OF THE MEMBER BUCKLING OF COLD-ROLLED ALUMINIUM ALLOY 5052 CHANNEL COLUMNS Ngoc Hieu Pham 1 *, Cao Hung Pham 1 and Kim J.R. Rasmussen 1 1 School of Civil Engineering, The University of Sydney, New South Wales, Australia E-mails: ngochieu.pham@sydney.edu.au, caohung.pham@sydney.edu.au, kim.rasmussen@sydney.edu.au Abstract: In recent years, BlueScope Permalite in Australia has used the existing rolling system for cold-formed steel sections to successfully roll-form aluminium alloy sections. In comparison with the conventional extrusion method, the roll-forming process is faster, more cost-effective and may enhance the strength of the aluminium alloy. This paper presents a series of compression tests on cold-rolled aluminium alloy 5052 lipped channels subjected to member buckling. A total of 28 tests of three commercially available sections including C10030, C25025 and C40030 were conducted. Two end boundary condition configurations were designed for test rigs. In the first configuration, the end sections of the specimens rotate freely about the major axis whereas rotation about the minor axis is restrained. In contrast, for the second configuration, restrained and free rotation conditions are used for major and minor axes respectively. Both flexural-torsional buckling and local-global interaction buckling failure modes were observed during the tests. The experimental results are compared with the predictions in Specification for Aluminum Structures 2015 by The Aluminum Association. Keywords: Cold-rolled Aluminium Alloy; Experimental Investigation; Member buckling; Channel columns. DOI: 10.18057/ICASS2018.P.111 1 INTRODUCTION Aluminium alloy structures have increasingly been used in structures such as bridges, building facades, roof and wall systems [1] due to their excellent corrosion resistance, high strength to weight ratio and the convenience of transportation and assembly. Two methods are normally used to produce aluminium alloy sections. The first and conventional method is extrusion commonly used around the world whereas roll-forming is the second and new method recently introduced by BlueScope Permalite in Australia [2] to produce roll-formed aluminium alloy sections. In recent years, BlueScope Permalite has successfully roll-formed two trial sections, including Channel and Zed sections, within acceptable dimensional tolerances, and demonstrated that it is possible to roll-form other aluminium alloy sections by utilizing the existing rolling system of cold-formed steel sections. It is found that the roll-forming process is faster and more cost-effective than the extrusion process, and may enhance the strength of the material. Hence, the competitive advantages of roll-formed aluminium sections should be commercialized in the worldwide market. Currently, there are no design guidelines for cold-rolled aluminium alloy members. Past research has focused on extruded aluminium alloy and has produced a huge amount of experimental data. However, experimental studies of cold-rolled aluminium alloy members remain limited. Roll-formed aluminium sections considered as thin-walled sections are therefore prone to local, distortional and global buckling instabilities. Hence, the behaviours of