| ABSTRACT:The orthotropic steel deck is an integral structure composed of longitudinal rids and transverse diaphragms, those are bearing deck loads together. Because of many advantages such as light deadweight, little material, large load-bearing capacity and short construction time etc, it is often applied for long-span bridges. With the wide application of the orthotropic steel bridge deck, the fatigue crack problems are becoming more and more prominent. It is very necessary to study the reasons and find the reasonable, effective, preventive measures and strengthening methods. Based on consulting a large number of domestic and foreign literatures, by means of the finite element software ABAQUS, the fatigue crack of the orthotropic steel bridge deck were studied in this paper. The main contents are listed as follows:(1)The history and current situation of application of orthotropic steel deck bridge were had viewed, the research methods on the orthotropic steel deck fatigue cracking problems were summarized. Besides, existing problems were brought forward, and then the objective and significance of this study were presented.(2)The fatigue cracking problem was analyzed in theory. Main factors affecting the fatigue cracking were discussed; methods of fatigue assessment and fatigue life calculation were summarized; common methods of fatigue design of steel bridge were summarized. The domestic and foreign specifications (especially British Standards BS5400) on the relevant provisions of fatigue were introduced.(3)Some finite element models were established for the orthotropic steel bridge deck with abaqus6.11software, so the fatigue crack was analyzed by numerical simulation. According to the finite element analysis, several positions in high incidence area of fatigue crack of orthotropic steel bridge deck were found. The mechanical mechanism of the fatigue cracks were discussed. Based on those results, Main causes of the premature fatigue cracks in bridge was analyzed.(4)Several kinds of schemes to treat fatigue cracks and to reinforce the deck were proposed corresponding to the fatigue cracks in the deck. Also three kinds of finite element models of the whole bridge had been established separately for three different schemes. Reference to British Standard BS5400, the stress history, fatigue load spectrum and the remaining fatigue life of the main fatigue concerns for the3kinds of schemes were compared. Thus it was concluded that the3different crack control schemes. Finally, combining with practical engineering, several proposals about the comprehensive treatment of fatigue cracks of the orthotropic steel deck were gave. |
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