钢结构桥梁交通荷载特征和正交异性钢桥面板疲劳机理研究-结构工程专业论文.docxVIP

ABSTRACT Orthotropic steel deck is an integral structure composed of bridge deck, longitudinal stiffener rib and diaphragm plate. Owing to advantages like saving material, light weight, high ultimate bearing capacity, short construction period and so on, orthotropic steel deck is widely applied to long-span bridges at domestic and foreign countries. However, orthotropic steel deck’s complex structure leads to prominent fatigue cracking phenomenon under axle cyclic load, especially at the intersection of longitudinal ribs and diaphragm plate, where fatigue cracks of varying degrees are found in bridge instances around the world. In this paper , by integrating Haihe Bridge inspection report, in-situ testing and finite element analysis, fatigue performance and stress state of orthotropic steel deck were studied, fatigue life of connection details were estimated . The main research contents are as follows: （1） Stress response of diaphragm plate of Haihe Bridge was measured while recording the traffic. Simplified vehicle load spectrum was obtained through data processing. （2） Finite element model of steel box girder of Haihe Bridge were built using ABAQUS. Applying simplified vehicle load spectrum, stress history of diaphragm plate of Haihe Bridge were calculated .The measured and calculated stress history were compared using rain-flow count method to verify the simplified vehicle load spectrum. （3） With the verified load spectrum, stress and strain history of connection details of Haihe Bridge（with and without brace） were calculated and fatigue life of these connection details was estimated. Fatigue performance of connection details of Haihe Bridge was compared before and after setting up the brace. （4） After cutting Residual stress was imported into submodel of diaphragm plate, fatigue life of arc-shape cutout was recalculated. Taking average stress into account, fatigue life of arc-shape cutout was estimated again. （5） Stress state variation of connection details