Local Buckling of RBS Beams Subjected to Cyclic Loading

This paper presents an analytical study of local instability behavior in a reduced beam section (RBS) beam subjected to cyclic loading. A general finite-element method is used for numerical experiments here. Even though lateral instability in the RBS beam is prevented, strength deterioration may occur due to local buckling of the RBS portion. The writers suggest that stiffeners arranged in the RBS portion can delay the occurrence of local buckling. To address the possibility that reinforcement of the RBS portion might offset the advantage of RBS, the stress distribution of beam end of the RBS with stiffeners was compared to that of an RBS beam without stiffeners. Stiffening the RBS portion did not cause an excessive stress concentration. These analyses suggest that an RBS beam can be sufficiently strengthened by placing two stiffeners at the boundaries that divide the RBS portion into three equal regions and the stiffener thickness required is the same thickness as the web.