Abstract The hot spot stress method recommended by the CIDECT Design Guide 8 cannot be directly used in the fatigue design of galvanized tubular steel connections since: (1) the hot-dipping process can sometimes significantly change the residual stress magnitude and distribution at the welded joint; and (2) sufficiently large vent and drain holes must be specified at the welded joint location prior to galvanizing, and quite often at the locations recommended by the design guide for calculation of hot spot stresses. Hence, the existing formulae and charts for determination of Stress Concentration Factors (SCFs) may not be applicable. In this study, Finite Element (FE) modelling was performed to examine the existing SCF formulae for welded rectangular hollow section (RHS) T-connections under brace in-plane bending. The FE models were validated by comparison of the experimental results from six large-scale connection tests. A parametric study including 192 FE models with varied hole locations, brace-to-chord width ratios, chord wall slendernesses, and brace-to-chord thickness ratios, shows that the existing SCF formulae can lead to unsafe predictions. Critical hot spot stress locations are thus identified. The effects of both brace in-plane bending and chord loading were studied. New design formulae that take the vent and drain holes into account are proposed. These formulae are shown to provide more accurate predictions of SCFs in such connections.

中文翻译：

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带镀锌孔的 RHS T 型连接在面内弯曲下的应力集中系数

摘要 CIDECT 设计指南 8 推荐的热点应力方法不能直接用于镀锌管钢连接的疲劳设计，因为： (1) 热浸工艺有时会显着改变焊接接头处的残余应力大小和分布。 ; (2) 必须在镀锌前在焊接接头位置指定足够大的排气孔和排水孔，而且通常在设计指南推荐的用于计算热点应力的位置。因此，用于确定应力集中系数 (SCF) 的现有公式和图表可能不适用。在本研究中，进行了有限元 (FE) 建模以检查在支撑面内弯曲下焊接矩形空心截面 (RHS) T 型连接的现有 SCF 公式。通过比较六次大规模连接测试的实验结果，对有限元模型进行了验证。一项包含 192 个具有不同孔位置、支撑与弦宽比、弦壁细长和支撑与弦厚比的 FE 模型的参数研究表明，现有的 SCF 公式可能导致不安全的预测。从而确定关键热点应力位置。研究了支撑面内弯曲和弦载荷的影响。提出了将通风孔和排水孔考虑在内的新设计公式。显示这些公式可以更准确地预测此类连接中的 SCF。和支撑弦厚比，表明现有的 SCF 公式会导致不安全的预测。从而确定关键热点应力位置。研究了支撑面内弯曲和弦载荷的影响。提出了将通风孔和排水孔考虑在内的新设计公式。显示这些公式可以更准确地预测此类连接中的 SCF。和支撑弦厚比，表明现有的 SCF 公式会导致不安全的预测。从而确定关键热点应力位置。研究了支撑面内弯曲和弦载荷的影响。提出了将通风孔和排水孔考虑在内的新设计公式。显示这些公式可以更准确地预测此类连接中的 SCF。