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为研究货运繁重公路上某正交异性钢桥面弧形切口开裂现象,基于动态称重系统(WIM)得到了疲劳车模型,并建立了钢箱梁节段模型和桥面板子模型,开展了该钢桥弧形切口应力响应分析和疲劳寿命评估。研究表明:横隔板弧形切口的应力局部效应非常明显,其横桥向应力影响线长度在2个纵肋范围左右,纵桥向应力影响线长度在2个横隔板范围左右;弧形切口仅能分辨轴组,而不能分辨轴组内单轴,因而1辆疲劳车加载可以在弧形切口产生2个大应力幅,分别对应中间双联轴和后面的三联轴;弧形切口在最小净截面处存在显著应力集中,周围存在明显的应力梯度,越靠近弧形切口边缘,应力梯度越明显,其最大主应力方向与实桥开裂形态相符;面内应力显著主导弧形切口应力响应,横隔板存在一定的面外变形,适当增加横隔板的厚度,可有效降低弧形切口应力水平;考虑轮载横桥向分布,纵肋R18和R19之间的弧形切口疲劳寿命为6~13年,这与实桥弧形切口疲劳开裂时间和位置均比较吻合;货车通行比例高、通行量大和超载严重是导致该桥过早出现疲劳开裂的主要原因;提出的实测疲劳车模型能为货运繁重公路上的钢桥,特别是正交异性钢桥面板疲劳设计和评价提供重要的参考。
In order to study the phenomenon of arc-shaped incision of orthotropic steel deck on freight-heavy highway, fatigue model was obtained based on Dynamic Weighing System (WIM), and the steel box girder segment model and bridge deck model were established. Stress Analysis and Fatigue Life Assessment of Arc Curved Cut for the Steel Bridge. The results show that the stress local effect of the arc-shaped incision of the diaphragm is very obvious. The influence length of transverse stress is about 2 longitudinal ribs and the influence length of longitudinal stress is about 2 diaphragms. The incision can only distinguish the shaft group, but can not distinguish the shaft group within a single axis, so a fatigue truck load can generate two large stress amplitude in the arc incision, corresponding to the middle double shaft and the back triple shaft; There is significant stress concentration at the minimum net section and obvious stress gradient around. The closer to the edge of the arc-shaped incision, the more obvious the stress gradient is. The direction of maximum principal stress is consistent with that of the real bridge. The in-plane stress significantly dominates the stress response , Transverse diaphragm has some out-of-plane deformation, the appropriate increase in the thickness of the diaphragm, which can effectively reduce the arc-shaped incision stress level; considering the wheel-side transverse distribution, longitudinal rib R18 and R19 between the arc-shaped notch fatigue life 6 to 13 years, which is in line with the actual time and location of the arc fracture crack fatigue crack location and location are more consistent; truck traffic ratio is high, heavy traffic and overload is the leading cause of the bridge fatigue fatigue cracking the main reason; the proposed measured fatigue Steel is the model can heavy road freight, particularly steel deck fatigue design and evaluation of important reference.