Rotation capacity of I‐shaped beams collapsed with lateral‐torsional buckling under reversed axial forces

Abstract

Abstract I‐shaped beams installed in a braced structure are subjected to reversed axial forces during earthquakes. Previously, we have derived the evaluation index and formulae for beams that collapsed with dominant local buckling. In this paper, we present additional experiments and numerical analyses conducted to clarify the influences of lateral‐torsional buckling on structural performances. Based on the results obtained, a new evaluation index is proposed by employing the normalized slenderness ratio introduced in this research. Finally, the applicability of the previous equation of Bauschinger effect coefficient is investigated to calculate the hysteretic energy dissipation.

Keywords

• I‐shaped beam
• reversed axial force
• lateral‐torsional buckling
• rotation capacity
• energy dissipation capacity