Flexural behaviour and design of cold-formed aluminium channel sections with elongated and circular web holes

Résumé fourni par la source

The use of cold-formed aluminium (CFA) channel sections in harsh environments could be a feasible alternative to cold-formed steel (CFS), where web holes are often provided in the beam member to accommodate electrical and plumbing services. When web depth is limited, elongated holes are preferred over circular ones, though they can considerably reduce flexural capacity. To mitigate this effect, stiffeners are often added around the hole edges. Currently there is very limited research available on the flexural behaviour of CFA channel sections with different types of web holes. This study investigates the moment capacity of CFA channels with various types of web openings, using experimentally validated finite element (FE) models. A comprehensive parametric study is conducted using 1168 FE models to investigate the effects of cross-section size, web hole shape and size, and stiffener length for four different cases: (i) elongated unstiffened, (ii) elongated stiffened, (iii) circular unstiffened, and (iv) circular stiffened CFA channel web holes. It is shown that the moment capacity of the sections considerably decreases as the web hole length-to-depth ratio ( b/d ) increases, with greater impact at higher hole diameter-to-depth ratios ( a/d ), on average by 14.3 % and 9.3 % for channels with unstiffened and stiffened web holes, respectively. The results also indicate that the current Direct Strength Method (DSM) design equations are conservative by 11 %, 9 %, 19 %, and 13 % for unstiffened elongated, stiffened elongated, unstiffened circular, and stiffened circular web holes, respectively. As a result, two sets of new DSM-based design equations are proposed for each scenario to predict local buckling and distortional/local-distortional buckling of CFA channel with web holes. Finally, the robustness of these equations is confirmed through reliability analysis, with a reliability index greater than 2.5 for all cases.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.