Bending collapse theory of thin-walled twelve right-angle section beams

•The theoretical bending collapse mechanism of the TTRS beams is presented.•The expressions of the bending moments are derived.•The c/h ratio has a great influence on the theoretical calculation.•The theoretical calculations have a good accuracy when 17.5

The present paper focuses on the bending collapse behavior of the twelve right-angle section (TTRS) beams. This paper presents the theoretical bending collapse mechanism of the TTRS beams around two axes based on the kinematic approach, and derives the expressions of the bending moments. The accuracy of the theoretical calculations are validated respectively by performing 36 groups finite element simulations including three kinds of materials, three different section dimensions and four different thicknesses. The results show that for 17.5