Double-sided weld is an effective way to improve the fatigue performance of orthotropic steel bridge decks (OSBD). However, the fatigue performance and optimization design methods of double-sided welds connecting the U-rib and the deck in OSBD require further study. In this paper, the finite element modeling method suitable for the notch stress approach in double-sided welds is discussed, and its variance from that of the single-sided weld is revealed. All possible fatigue failure modes of double-sided welds, the transfer phenomenon of fatigue crack initiation location and the change of fatigue failure modes under different vehicle loading conditions are revealed. It is further discussed that how the change of the deck plate thickness and the weld foot length alters the fatigue failure mode under the same loading condition. According to the above analysis, in order to obtain the optimal fatigue performance of double-sided welds, an optimal design method based on the fatigue damage factor per unit time under real vehicle loading conditions is proposed. The analysis results show that the fatigue failure modes of the double-sided welds of the U-rib-to-deck welded joint in the OSBD is determined by three factors: loading condition, deck plate thickness and weld foot length. According to the optimization factor proposed in this paper, the thickness of the deck plate and the length of the weld foot can be reasonably determined under different traffic loading conditions, so that the fatigue performance of the rib-to-deck joint in the OSBD is optimized.

双面焊缝是改善正交异性钢桥面板（OSBD）疲劳性能的有效方法。但是，在OSBD中连接U型肋和甲板的双面焊缝的疲劳性能和优化设计方法需要进一步研究。本文讨论了适用于双面焊缝缺口应力方法的有限元建模方法，并揭示了其与单面焊缝的差异。揭示了在不同的车辆载荷条件下，双面焊缝的所有可能的疲劳失效模式，疲劳裂纹萌生位置的传递现象以及疲劳失效模式的变化。进一步讨论了在相同的载荷条件下，盖板厚度和焊脚长度的变化如何改变疲劳破坏模式。根据以上分析，为了获得最佳的双面焊缝疲劳性能，提出了一种基于实际车辆载荷条件下单位时间疲劳损伤因子的优化设计方法。分析结果表明，OSBD中U型肋对甲板焊接接头的双面焊缝的疲劳失效模式是由三个因素决定的：加载条件，盖板厚度和焊脚长度。根据本文提出的优化因子，可以在不同的交通负荷条件下合理确定盖板的厚度和焊脚的长度，从而使OSBD肋骨-甲板接头的疲劳性能达到优化。提出了一种基于实际车辆载荷条件下单位时间疲劳损伤因子的优化设计方法。分析结果表明，OSBD中U型肋对甲板焊接接头的双面焊缝的疲劳失效模式是由三个因素决定的：加载条件，盖板厚度和焊脚长度。根据本文提出的优化因子，可以在不同的交通负荷条件下合理确定盖板的厚度和焊脚的长度，从而使OSBD肋骨-甲板接头的疲劳性能达到优化。提出了一种基于实际车辆载荷条件下单位时间疲劳损伤因子的优化设计方法。分析结果表明，OSBD中U型肋对甲板焊接接头的双面焊缝的疲劳失效模式是由三个因素决定的：加载条件，盖板厚度和焊脚长度。根据本文提出的优化因子，可以在不同的交通负荷条件下合理确定盖板的厚度和焊脚的长度，从而使OSBD肋骨-甲板接头的疲劳性能达到优化。分析结果表明，OSBD中U型肋对甲板焊接接头的双面焊缝的疲劳失效模式是由三个因素决定的：加载条件，盖板厚度和焊脚长度。根据本文提出的优化因子，可以在不同的交通负荷条件下合理确定盖板的厚度和焊脚的长度，从而使OSBD肋骨-甲板接头的疲劳性能达到优化。分析结果表明，OSBD中U型肋对甲板焊接接头的双面焊缝的疲劳失效模式是由三个因素决定的：加载条件，盖板厚度和焊脚长度。根据本文提出的优化因子，可以在不同的交通负荷条件下合理确定盖板的厚度和焊脚的长度，从而使OSBD肋骨-甲板接头的疲劳性能达到优化。