Stepwise regression approach for lateral-distortional buckling capacity assessment of cellular steel beams

Assessment of the ultimate capacity of the cellular steel beams subjected to the lateral-torsional buckling containing web distortion (lateral-distortional buckling) was rarely investigated. So far, there is no accurate formula to predict the lateral-distortional buckling (LDB) capacity of such members. Here, extensive simulations (660 specimens) based on the nonlinear finite-element analysis (FEA) were carried out to simulate the cellular steel beams in distortional buckling mode. The influence of eight parameters that may affect the LDB capacity was deeply investigated. Then, the stepwise regression (SR) approach progressed as a predictive model to obtain a formula for measuring the failure moment capacity of the cellular steel beams. The data were used for the SR model development obtained from the FEM simulations that were done initially. It was attempted to derive an exact enough formula, which considers all the variables that may affect the LDB capacity of cellular steel beams. The validation of the SR model has been also further verified. Finally, a comparison was performed between the proposed formula and the predictions obtained from AS4100, EC3, and, AISC codes. It was shown that the proposed formula is enough to exact and applicable to use by practicing engineers. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.