Ayrton-Perry approach for the lateral-torsional buckling resistance of mono-symmetric I-section beams

• Extension of the new Ayrton-Perry approach to mono-symmetric I-section beams. • Calibrated numerical model for the force-displacement response of mono-symmetric beams. • Large parametric study for various loading conditions. • Forthcoming inclusion as an amendment to the new version of the Eurocode 3. The Ayrton-Perry approach is the base of the Eurocode 3 design rules for the verification of the buckling resistance of prismatic members, in which different buckling curves associated to different imperfection factors are suggested according to the sections, steel grades, and other parameters. In the revised version of Eurocode 3, the lateral-torsional buckling resistance of simply-supported doubly-symmetric I-section beams is prescribed using a formulation based on the Ayrton-Perry approach and combined with a calibrated generalized imperfection. However, for mono-symmetric I-beams, the General Case predicted in the last version of Eurocode 3 has been maintained, which results in large scatter and an inconsistent design. This paper extends the new Ayrton-Perry approach available in the new version of Eurocode 3 to deal with simply supported mono-symmetric I-section beams under different loading conditions. An advanced numerical model is built and validated to conduct a reliable parametric study in order to assess the available design methodologies and the proposed extended formulation. It is concluded that the proposed formulation exhibits safe-sided results which better agreement with experimental results and advanced numerical simulations, providing more economic and sustainable solutions for mono-symmetric members.