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全空间S-N曲线是利用时序准则进行钢箱梁正交异性桥面板疲劳评估的基础。首先基于钢桥设计规范给出的有限疲劳寿命区S-N曲线,从理论上推导了覆盖低周疲劳寿命区、有限疲劳寿命区和高周疲劳寿命区的一般全空间S-N曲线模型。进一步针对小型汽车和日常风等荷载引起的低水平应力幅以及地震和强风等荷载引起的高水平应力幅,引入高周疲劳损伤累积因子和低周疲劳强度调整因子分别对低水平应力幅和高水平应力幅造成的疲劳损伤进行计算,提出一种适用于钢箱梁正交异性桥面板疲劳评估的全空间S-N曲线模型。在此基础上对模型参数的几何意义进行了解释。最后采用正交异性桥面板顶板-U肋疲劳试验数据对模型参数进行了估计,得到了具有最佳拟合度的全空间S-N曲线和具有99%保证率的疲劳评估全空间S-N曲线。研究结果表明,该文提出的全空间S-N曲线模型能准确描述钢箱梁正交异性桥面板在各种应力幅下的疲劳损伤累积特性。研究结果可为钢箱梁正交异性桥面板的疲劳评估奠定基础。
Full-space S-N curve is the basis for the fatigue assessment of steel box girder orthotropic bridge deck by using the time-series criterion. First, based on the S-N curve of the finite fatigue life zone given by the steel bridge design code, a general full-space S-N curve model covering the low-cycle fatigue life zone, the finite fatigue life zone and the high-cycle fatigue life zone is theoretically derived. Further, low-level stress amplitude caused by loads such as small cars and daily wind and high-level stress amplitude caused by earthquakes and strong wind loads are introduced. The high-cycle fatigue damage cumulative factor and low-cycle fatigue strength adjustment factor are respectively introduced to low-level stress amplitude and high Horizontal stress amplitude fatigue damage calculation, proposed a steel box girder orthotropic bridge fatigue assessment of the full space SN curve model. On this basis, the geometric meaning of the model parameters is explained. Finally, the parameters of the model were estimated by using the U-rib fatigue test data of orthotropic bridge deck roof panel. The full-space S-N curve with the best fitting degree and the S-N curve of fatigue assessment with 99% guaranteed rate were obtained. The results show that the full-space S-N curve model proposed in this paper can accurately describe the fatigue damage characteristics of steel box girder orthotropic bridge deck under various stress amplitude. The results can lay a foundation for the fatigue assessment of steel box girder orthotropic bridge deck.