正交异性钢桥面环氧沥青铺装层疲劳耐久极限研究

虎门二桥坭洲水道桥为主跨1688m的双塔钢箱梁悬索桥,桥面采用正交异性钢桥面板环氧沥青铺装层结构。为提高该桥环氧沥青铺装层的使用寿命,研究环氧沥青铺装层疲劳耐久性的极限受力影响因素,基于小梁试件四点弯曲疲劳试验,采用Abaqus软件建立局部梁段三维有限元模型,分析最不利荷载位置处铺装层的极限受力情况。结果表明:环氧沥青混合料的疲劳耐久极限为578με;随着铺装层弹性模量的增大,铺装层的应力、应变显著减小,其疲劳耐久极限模量为2687MPa;环氧沥青铺装层的应变与车辆接地压强呈正相关关系,该桥铺装层的疲劳耐久极限接地压强为1.59MPa。适当提高环氧沥青铺装层的弹性模量,并应严格控制通行车辆的轴重,可以提高该桥的铺装层耐久性。

Study on Fatigue Durability of Epoxy Asphalt Pavement on Orthotropic Steel Bridge Deck

The Nizhou Waterway Bridge of the Second Humen Bridge is a double-tower steel box girder suspension bridge with a span of 1 688 m, consisting of an orthotropic steel deck paved with epoxy asphalt mixture. In order to improve the service life of the epoxy asphalt overlay of the bridge, we studied the influential factors on ultimate stress of the fatigue durability of the epoxy asphalt pavement. Based on the four-point bending fatigue tests of beam specimens, a three-dimensional finite element model of local beam section was established by using the Abaqus software to analyze the ultimate stress of the pavement at the most unfavorable sites. The results show that the fatigue endurance limit of epoxy asphalt mixture is 578με;the stress and strain of pavement significantly decrease with the increase of elastic modulus of overlay, and the fatigue endurance limit is about 2 687 MPa. What′s more, the strain of the epoxy asphalt pavement layer is positively correlated with the grounding pressure of the vehicle, and the grounding pressure for the fatigue endurance limit is 1.59 MPa. Consequently, the elastic modulus of the epoxy asphalt overlay should be appropriately increased, and the axle load of the passing vehicle should be strictly controlled, so that the durability of the pavement layer of the bridge can be improved.