Multiple flaws are widely observed on the surface of corroded steel bridge wires, and the interaction between flaws can increase the stress intensity factor (SIF) to drive cracking. But the flaw combination criterion provided for plates in codes is not straight-ford to evaluate interacting surface cracks in steel wires. A model containing twin co-planar semi-elliptical surface cracks throughout a circular cross-section is thus established to investigate crack propagation of steel wires under axially tension in terms of initial crack shape, size and relative spacing. A new combination rule using a virtually effective crack is then proposed for interacting co-planar surface cracks based on the SIF amplification effect, which is quantified as a function of the initial crack aspect ratio, crack depth and relative spacing. The shape development of twin surface cracks is also simulated by numerical analysis based on the Paris law. The results show that the multiple-crack growth is sensitive to both the initial crack size and relative spacing, and the interaction should be considered for the neighbouring cracks when their relative spacing is within the crack depth range (s ≤ a). The comparison of the predicted fatigue lives between twin cracks and corresponding effective crack confirms the feasibility of the presented combination criteria.

在锈蚀的钢桥线表面上广泛观察到多个裂纹，并且裂纹之间的相互作用可以增加应力强度因子（SIF）来驱动裂纹。但是，在规范中为钢板提供的缺陷组合准则并不是很容易评估钢丝中相互作用的表面裂纹。因此，建立了一个在整个圆形横截面上包含双共面半椭圆形表面裂纹的模型，以研究在轴向张力下钢丝的裂纹扩展，包括初始裂纹形状，尺寸和相对间距。然后，基于SIF放大效应，提出了一种使用几乎有效的裂纹的新组合规则来相互作用共面的表面裂纹，并根据初始裂纹纵横比，裂纹深度和相对间距进行量化。根据巴黎定律，通过数值分析也模拟了双表面裂纹的形状发展。结果表明，多裂纹扩展对初始裂纹尺寸和相对间距均敏感，当相邻裂纹的相对间距在裂纹深度范围内时，应考虑相互作用。小号 ≤ 一个）。对双裂纹和相应有效裂纹之间的预期疲劳寿命的比较证实了所提出的组合标准的可行性。