Experimental and Numerical Investigations on Closely Spaced Built-Up Angle Members

This paper presents the results of 10 laboratory tests performed on closely spaced built-up members fabricated from hot-rolled angle sections. Such members are of special interest in the construction and reinforcement of steel lattice towers used for telecommunication or electrical transmission lines. The angle sections used in this study were star-battened with pinned support conditions. In particular, two configurations were studied: star-battened angles with equal sections (SBE) (composed of two chords with the same section), and star-battened angles with unequal sections (SBU) (composed of two chords with different sections). The influence of connection spacing along the members and different types of connections (fully preloaded bolts, partially preloaded bolts) were also studied. In addition, the important influence of geometric imperfections on failure load and failure mode were analyzed. In this paper, a numerical model is introduced after the laboratory tests are presented. The model was built in ANSYS version 18.2 and was validated based on the results obtained during the experimental campaign. The numerical results highlighted the sensitivity of failure modes to initial imperfections (out-of-straightness, load eccentricity). Last, the validated numerical model is thought to be used in a wider parametric study with the aim of developing new design recommendations.