Behaviour and capacity of steel angles in compression

轧制的单角钢型材经常用于各种结构中，包括例如钢托梁和桁架，以及格构式输电塔和类似的通信结构。在许多实际应用中，角材可以仅通过一条腿螺栓连接或焊接到其他结构构件上。这导致轴向载荷相对于横截面质心的偏心，从而导致双轴弯曲和压缩载荷情况下的可能扭转。这种连接结构与角形截面的非对称特性相结合，导致单角形构件的设计比双对称截面（如W形）的设计更复杂。对于角钢的设计，现行的单角钢构件LRFD规范（AISC 2000）建议使用与双对称截面类似的相互作用方程。使用这些方程的预测值与现有试验结果的比较表明，虽然在大多数情况下，方程是不必要的保守，但在其他情况下，它会导致不保守的设计值。在现行的加拿大钢结构设计规范（CSA S16-01）中，虽然建议使用相关方程进行角钢设计，但没有明确规定相关方程中使用的具体术语的确定。LRFD规范中相互作用方程保守性的不一致性以及加拿大钢结构设计规范中缺乏成文规定促使了这一建议。本建议的目的是研究长度细长比和端部偏心对相等和不相等支腿角的强度和性能的影响。将在不同的荷载组合下对实际尺寸的样本进行测试，并使用实验结果开发和验证分析模型。预计这一深入研究将进一步了解角钢的性能，并将对目前的设计程序进行重要的有益改进。

Rolled single steel angle sections are frequently used in a variety of structures including, for example, steel joists and trusses, and latticed transmission towers and similar communication structures. In many practical applications, angles may be either bolted or welded to other structural members by one leg only. This results in axial load eccentricity with respect to the centroid of the cross section resulting in bi-axial bending and possible torsion in the case of compression loads. Such connection configurations combined with the asymmetric characteristics of angle sections result in the design of single angle members more complex than that of doubly symmetric sections such as W shapes. For the design of steel angles, the current LRFD Specification for Single-Angle Members (AISC 2000) suggests the use of interaction equations similar to those developed for doubly symmetric sections. A comparison of predicted values using these equations with available test results has indicated that, while the equation, in most cases, is unnecessarily conservative, it results in  unconservative design values in  other instances. In the current Canadian steel design code (CSA S16-01), although the use of interaction equation is suggested for the design of steel angles, there are no provisions explicitly addressing the determination of specific terms used in the interaction equation. The inconsistencies in conservatism of the interaction equation in the LRFD specification and the lack of codified provisions in the Canadian steel design code motivated this proposal. The objective of this proposal is to study the effects of length slenderness ratios and end eccentricities on the strength and behaviour of both equal and unequal leg angles. Realistically sized specimens will be tested under different loading combinations and an analytical model will be developed and validated using the experimental results. It is anticipated that this in-depth study will further the understanding of the behaviour of steel angles and will result in important beneficial refinements to present design procedures.