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MECHANISM OF LONGITUDINAL SURFACE CRACKING IN PAVEMENTS ON STEEL BRIDGE DECKS

钢桥面铺装面纵向开裂机理

基本信息

批准号：
13650515
负责人：
NISHIZAWA Tatsuo
金额：
$ 1.79万
依托单位：
Ishikawa National College of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650515/
关键词：
pavement steel bridge deck longitudinal surface crack dissipation energy criterion finite element method fatigue analysis asphalt mixture 綱床版表面ひび割れ粘弾性解析縦ひび割れ

项目摘要

Longitudinal surface cracks (LSC) are often observed in asphalt pavements on steel bridge deck. The cracks appear longitudinally on pavement surface in wheel paths and their spacing coincides with a half of spacing of longitudinal ribs. The objective of this study is to find the causes and mechanism of the LSC. A condition survey was conducted on more than 50 steel deck bridges to investigate actual conditions of pavements on the bridges. The survey revealed that LSC actually starts from pavement surface but does not reach its bottom, and that they appear not only above the webs of main girder or longitudinal ribs but also between the webs. Behaviors of asphalt mixtures at high temperature were investigated. It was observed that at high temperature small cracks really occurred around aggregates and grew further. The reason of the cracking was that the aggregates vertically moved by wheel load and broke thin films of aged asphalt binder around the aggregates. A computer simulation was performed using a newly developed FE model, in which a steel deck structure is modelled with a strip element and the pavement on it is modelled with a prism element. To take into account viscosity of asphalt materials, the Burger model was incorporated. In the simulation, axle loads traveled over a pavement and variations of stresses and strains in the pavement with time were calculated. The dissipated energy in the pavement was estimated. The simulation results suggested that high dissipated energy at the pavement surface between webs might cause the LSC there, which was not able to be explained with fatigue analysis based on the tensile strain fatigue criterion.

钢桥面沥青混凝土铺装层经常出现表面纵向裂缝。在车辙中，路面表面出现纵向裂缝，裂缝间距约为纵向肋间距的一半。本研究的目的是寻找LSC的原因和机制。对50多座钢桥面桥进行了状况调查，以调查桥上路面的实际状况。调查结果表明，LSC实际上是从路面开始，但并没有到达路面底部，它们不仅出现在主梁腹板或纵肋的上方，而且还出现在腹板之间。研究了沥青混合料的高温性能。据观察，在高温下，小裂纹确实发生在骨料周围，并进一步增长。开裂的原因是集料在轮载作用下发生垂直移动，破坏了集料周围的老化沥青结合料薄膜。采用新开发的有限元模型进行了计算机模拟，其中钢桥面结构用条形单元模拟，其上的铺装层用棱柱体单元模拟。为了考虑沥青材料的粘度，Burger模型被并入。在模拟中，轴载通过路面和路面的应力和应变随时间的变化进行了计算。估算了路面的耗能。模拟结果表明，腹板间路面表面的高耗能可能是导致该处出现LSC的原因，而基于拉应变疲劳准则的疲劳分析无法解释该现象。