Buckling resistance of star-battened angle members made of high-strength steel

Recent upwards developments of the power grid requests lead to use of high strength steels (HSS) for the design and construction of higher and heavier loaded steel lattice transmission towers, or to strengthen the existing ones. Usually star-battened sections are preferred for the strengthening of individual members or in case of very high compression loads. Thus, the investigations focus here on the bearing capacity of a star-battened member made of two S460 L250x250x28 angles. The objective was to use a star-battened member made of two S460 L300x300x35 angles with a member length of 4486 mm that will be used in a specific project of 240 m high power transition tower. However, as the request in terms of length capacity cannot be met by the testing labs in Belgium, the studies have concentrated on the profile made of L250x250x28 angles. Firstly, a critical review of the current European normative documents (EN 50341, EN1993-1-3, prEN1993-3) has been made and the buckling resistance of the above-mentioned profile has been evaluated. Then, an experimental compression test has been performed for this member. The test has been complemented by a full non-linear finite element simulation by means of ANSYS software. Experimental, numerical and analytical results have been compared and discussed. Finally, conclusions were drawn considering the design of S460 starbattened members in compression. These studies are part of an ongoing project entitled "New steel" funded by Elia and ArcelorMittal and involving the University of Lie`ge.