Lateral torsional buckling of steel beams with beam and shell elements

Abstract

This thesis investigates the lateral torsional buckling (LTB) of steel beams using beam element in STAAD and shell element in ANSYS. It aims to improve LTB prediction accuracy through comparative analysis of Eurocode 3 (EN 1993-1-1:2005, EN 1993-1-1:2022 ) and AISC 360-16 design codes, utilizing STAAD.Pro Advanced for computational modeling and ANSYS for finite element analysis (FEA).The study explores LTB phenomena, focusing on factors influencing LTB resistance, including the 3-factor formula, correction factors for load application points, and cross-section asymmetry. Simply supported and fixed supported beams are modeled in STAAD.Pro and validated with ANSYS simulations.

Findings show significant differences in LTB resistance predictions between the design codes. Eurocode 3 (EN 1993-1-1:2005) provides higher resistance values due to detailed considerations of load height and moment gradient effects, while AISC 360-16’s conservative approach does not address these factors, leading to potential safety discrepancies under nonstandard loading conditions. Benchmarking results of ANSYS align closely with manual calculations and STAAD outputs, confirming the reliability of theoretical methods. The thesis emphasizes using multiple validation methods to ensure robust LTB predictions.