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在多种焊接节点中产生的疲劳裂缝,也产生在大量细长正交异性钢桥面板中。一部分裂缝在桥梁投入使用短短几年之后便会出现,所以对于桥面焊接节点的疲劳寿命评估较复杂。这同时也是局部压应力会随着很多因素而随机变化的原因,尤其是那些在车胎、公路和钢结构的动力交互作用面上。提出并讨论了可观测裂缝的主要成因,以及具有梯形横截面和纵肋的正交异性桥面上典型焊接和几何细部的极限疲劳寿命的评估结果。以一现存长跨钢桥的桥面为例进行分析。该桥面曾经通过增加钢筋混凝土覆层,采用剪力螺栓连接到钢板面而加固。这些措施是为了防止后续更大的维修工作,并且提高钢桥面的疲劳寿命预期值。采用数值模型、试验性应变测量对疲劳寿命进行评估,还考虑了在该桥32年的使用年限中所有结构上的可变因素、交通流量、车载荷载。
Fatigue cracks generated in a variety of welded joints also occur in a large number of elongated orthotropic steel bridge deck. A few cracks occur after the bridge is put into operation for a few years, so the assessment of the fatigue life of bridge deck joints is complicated. This is also the reason why local compressive stress varies randomly with many factors, especially those of the dynamic interaction of tires, roads and steel structures. The main causes of observable fractures are presented and discussed as well as the evaluation results of the ultimate fatigue life of typical welding and geometrical details on orthotropic bridge deck with trapezoidal and longitudinal ribs. Taking an existing bridge span of steel bridge as an example for analysis. The deck has been strengthened by adding reinforced concrete cladding, using shear bolts attached to the steel surface. These measures are intended to prevent subsequent larger repairs and to increase the expected fatigue life of the steel deck. Fatigue life was assessed using numerical models and experimental strain measurements, and all structural variables, traffic flow, and vehicle loads over the 32-year service life of the bridge were taken into account.