Shear design rules for roll-formed aluminium lipped channel beams

Abstract

Aluminium sections are significantly used as primary load bearing members in the building industry due to its corrosion resistance, ease of fabrication and erection, and high strength-to-weight ratio. Roll-formed aluminium lipped channel beam (LCB) is one of these sections which are typically used as roof purlins, floor joists and rafter. However, LCBs are vulnerable to buckling failures due to the increased web slenderness and low elastic modulus compared to steel. Hence an experimental study was conducted at Griffith University to investigate the shear behaviour of these sections. Finite element models of aluminium LCBs were then developed and validated with test results. A detailed parametric study was also undertaken with different sections, web slenderness, aluminium grades and aspect ratios to obtain the shear strengths and shear buckling characteristics of aluminium LCBs. The ultimate shear capacities of aluminium LCBs obtained from the tests and finite element analyses (FEA) were compared with the current shear design rules of Australian/New Zealand Standard and Eurocode for both aluminium structures and cold-formed structures as well as direct strength method (DSM). The comparison showed that these current shear design rules are not suitable to predict the shear capacities of aluminium LCBs. Hence new design rules were proposed in this study to accurately predict the shear capacities of roll-formed aluminium LCBs. This paper presents the details of the experimental and numerical studies and the development of shear design rules based on Australian/New Zealand Standard, Eurocode and DSM.