Structural Stress Analysis Of Small And Medium Span Expanded Bridge

With the rapid development of economy in China, the existing volume of traffic increasing on the highway, the service quality of highway have a significant reduction, it can not effectively alleviate the problem of inadequate road capacity by relying on building new roads, therefor, the Highway Broaden Engineering is becoming more and more important. The bridge load standards have always been improved after expanding roads, so, the old bridges should be widened to meet the needs of traffic.The way of widening the highway bridges often determines the whole of the basic principles of road widening and technical standards. Therefore, the choice of the way of widening the old bridge is extremely important. To the bridge widening engineering, old and new bridges and there splicing sites will generate additional inner force, it was caused not only by their structural weight and two dead load effects but also by foundation settlement, shrinkage and creep of concrete and car load. Therefore, it is extremely important to analysis the inner force of old and new bridges in compliance with practical, economic, security, aesthetic principle.This thesis takes a simple box girder bridge as an example, according to the types of broaden bridges and the splicing methods, a summary of widening bridge is given. Build the bridge model by the finite element analysis software MIDAS, calculate the transverse load distribution and the horizontal distribution of internal forces before and after widening bridge according to different way of splicing methods; Calculate and analysis the influence of different settlement between the old and new bridge foundation in superstructure and the surface of its connecting; Calculate and analysis the influence of shrinkage and creep of concrete in superstructure and the surface of its connecting. The results can provide a useful reference on the design of medium span girder bridge's expansion.