Lateral torsional buckling (LTB) of I-beams is characterized by simultaneous lateral deflection and twist. In this paper the influence of destabilizing and neutral effects of loadings and the possibility of the occurrence of web distortion, which characterizes the lateral distortional buckling (LDB), is numerically investigated. Recent research has shown divergences between the standard procedures of the American Institute of Steel Construction, Australian Standards and Eurocode with LTB numerical results. In addition, some procedures have recently been proposed for correcting possible deviations between the results of numerical analysis and standard procedures. In order to investigate this situation, elastic stability and physical and geometrical nonlinear analyzes are performed, using GBTul and ABAQUS softwares, respectively. The numerical model is calibrated considering experimental tests. The beams are simply supported, with fork supports at the ends, and subject to neutral and destabilizing effects of loading. The beams are subject to uniform bending, mid-span concentrated load and uniformly distributed loads. The parametric study is performed by varying the geometric cross section parameters. The results are compared with international standards and analytical procedures. It is concluded that the influence of destabilizing and neutral effects of loadings is responsible for providing non-conservative results when compared to the American Institute of Steel Construction procedure. The occurrence of LDB in hot-holled I sections influences the lateral stability strength of I-beams, but it is not predominant. With the possibility of using the elastic critical moment obtained by the elastic stability analysis, the conservative situation of EC3 is verified. The Australian Standards procedure is in agreement with all the situations analyzed.

工字梁的横向扭转屈曲（LTB）的特征是同时发生横向偏斜和扭曲。本文通过数值研究了载荷的失稳和中性效应的影响以及发生腹板变形的可能性，腹板变形是横向变形屈曲（LDB）的特征。最近的研究表明，美国钢结构学会的标准程序，澳大利亚标准与具有LTB数值结果的欧洲规范之间存在分歧。另外，最近已经提出了一些程序来校正数值分析结果和标准程序之间可能的偏差。为了研究这种情况，分别使用GBTul和ABAQUS软件进行了弹性稳定性以及物理和几何非线性分析。考虑到实验测试，对数值模型进行了校准。梁的支撑简单，末端有叉形支撑，承受中性和不稳定作用。梁要承受均匀的弯曲，中跨集中载荷和均匀分布的载荷。参数研究是通过改变几何截面参数来进行的。将结果与国际标准和分析程序进行比较。结论是，与美国钢结构学会程序相比，载荷的不稳定和中性作用的影响可提供非保守的结果。在热孔I型截面中LDB的出现会影响工字梁的侧向稳定性强度，但不是主要因素。可以使用通过弹性稳定性分析获得的弹性临界矩，从而验证了EC3的保守情况。澳大利亚标准程序与所分析的所有情况相符。