Monosymmetric sections made from I-section beams with a channel cap welded to the top flange find use in crane runway beams or girders for medium duty cranes of moderate spans. These beams are susceptible to lateral-torsional buckling when the compression flange is laterally unsupported. In order to determine the critical elastic buckling moment several geometrical parameters must first be determined. Two of these are the shear centre location and the monosymmetry constant. These properties may be cumbersome to evaluate for these sections. A general equation for locating the shear centre is developed in this study and may be particularly useful for combinations of I-section and channel that are not standard or not found as standard combinations in books of data. The result is then used, in conjunction with other relevant properties, to evaluate the monosymmetry constant of the section using an approach previously suggested by other researchers. This approach is demonstrated to produce acceptable results when compared to benchmark values from books of data as well as output from suitable software. A suitable adjustment to the monosymmetry constant evaluated from the suggested approach is proposed and shown to give generally conservative values while retaining acceptable accuracy.

由I型截面梁制成的单对称截面，其通道盖焊接到顶部法兰，可用于中等跨度的中型起重机的起重机跑道梁或大梁。当压缩凸缘在横向上不受支撑时，这些梁易于发生横向扭转屈曲。为了确定临界弹性屈曲力矩，必须首先确定几个几何参数。其中两个是剪切中心位置和单对称常数。这些属性可能难以评估这些部分。在这项研究中，开发了一个用于确定剪切中心的通用方程式，该方程式对于非标准或在数据手册中未作为标准组合找到的I型截面和通道的组合可能特别有用。然后将结果与其他相关属性一起使用，使用其他研究人员先前建议的方法来评估截面的单对称常数。与数据手册中的基准值以及适当软件的输出相比，该方法可产生可接受的结果。提出了从建议的方法评估的对单对称常数的适当调整，并显示出通常的保守值，同时保持了可接受的精度。