The region close to plastic hinge is vulnerable to lateral instability due to the formation of the mechanism. A stable length between lateral restraint at the plastic hinge and adjacent lateral restraint plays a significant role in preventing lateral instability and until after the required hinge rotation has taken place. This phenomenon is studied for beams under uniform moment loading by carrying out an extensive parametric study on a mixed set of I-shaped hybrid and homogeneous plate girders using nonlinear finite element analysis. Geometric dimensions and steel grade of plate girder elements are varied to account for their effect on member slenderness. Effect of overall slenderness is included by varying lateral bracing configuration. Attention is given to the interaction between local and lateral buckling and their influence on inelastic rotation. Regression analysis of the database is carried out to arrive at a prediction equation for stable length to achieve the required rotation capacity. The equation is validated by applying it to thirty-nine selected experiments conducted by others and comparing results with the results of available prediction equations. Statistical analysis of the validation study shows that the proposed equation provides more refined results as compared to available equations. It is observed that use of the new prediction equation when used along with rotation capacity prediction equation suggested by authors in the previous study proves to be a rational solution as available stable length equations that are based only on geometric proportions of sections. At the end of the paper, a flowchart and demonstration examples for use of these equations are presented.

中文翻译：

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考虑延展性要求的非弹性设计中的稳定长度

由于机制的形成，靠近塑性铰的区域容易受到横向不稳定性的影响。塑性铰的侧向约束和相邻的侧向约束之间的稳定长度在防止横向不稳定方面起着重要作用，直到发生所需的铰链旋转之后。通过使用非线性有限元分析对 I 形混合和均质板梁的混合组进行广泛的参数研究，研究了均匀力矩载荷下梁的这种现象。板梁元件的几何尺寸和钢级是变化的，以说明它们对构件细长的影响。整体细长的影响包括在不同的横向支撑配置中。注意局部和横向屈曲之间的相互作用及其对非弹性旋转的影响。对数据库进行回归分析，得出稳定长度的预测方程，以达到所需的旋转能力。该方程通过将其应用于其他人进行的 39 个选定实验并将结果与​​可用预测方程的结果进行比较来验证。验证研究的统计分析表明，与可用方程相比，所提出的方程提供了更精确的结果。观察到，将新的预测方程与之前研究中作者建议的旋转能力预测方程一起使用被证明是一个合理的解决方案，因为可用的稳定长度方程仅基于截面的几何比例。在论文的最后，给出了使用这些方程的流程图和演示示例。