Investigation on shear behaviour and design for aluminium alloy with circular edge stiffened holes with shear span ratio 1

Abstract

Cold-formed aluminium (CFA) structural members are increasingly being adopted in engineering applications due to their favourable strength-to-weight ratio, corrosion resistance, recyclability, and long-term durability in harsh environments. A promising application lies in lightweight framing systems, where circular service holes in the web accommodate mechanical, electrical, and plumbing (MEP) installations. However, such openings significantly reduce shear capacity, leading to premature buckling and distortion. This study investigates the shear behaviour of CFA channel sections with unstiffened and edge-stiffened circular web holes through nonlinear finite element (FE) analysis, validated against experimental results from the literature. The FE models demonstrated strong predictive capability, with mean FEA-to-test ratios of 1.02 for aluminium and 1.07 for cold-formed steel, and low coefficients of variation (<0.06). A comprehensive parametric study is done by simulations evaluated the effects of hole size, stiffener length, section depth, thickness (2.0- 3.5 mm), and alloy grade (H36 and H38). The results showed that unstiffened holes reduced shear capacity by up to 60% (at dw/d1-0.6), while edge stiffeners effectively regained 15-40% of the lost strength. Increasing thickness from 2.0 to 3.5 mm more than doubled shear capacity,and the H38 alloy consistently outperformed H36 due to its higher yield strength. Comparisons with international design standards ([AISI 2016], [AS/NZS 2018], and [ADM 2015]) revealed that current provisions are conservative for plain webs but underestimate the strengthening contribution of edge stiffeners. To address these shortcomings, new design equations based on a modified Direct Strength Method (DSM) were proposed, incorporating shear reduction factors and elastic buckling coefficients tailored for aluminium members with web perforations. The findings contribute to safer and more efficient design of cold-formed aluminium systems, supporting the integration of perforated channels in modern construction practice.