Research About Fatigue Property Of The Connections Of Track Cross Beam And Integral Joint

Along with the development of scientice and technology, steel bridge's span and the development of welding technology have got a great developement, a new-type steel bridge's structure integral joint has been regular adopted in the last few years. Not only are welding seams dense, but also the types of welding seams are various in the integral joint. The fatigue resistance of complicated welded structure subjected to moving vehicle loads needs to be further researched. To the long span steel truss bridge, joint fatigue damage is the main-type destroys. In this thesis, the study method combining theory calculation with model test is adopted Based on Chongqing Caiyuanba Yangtze Bridge, the fatigue reliability of the connecting of track cross beam and integral joint is studied.First of all, some basic conceptions of steel bridge fatigue are introduced, and some basic theories about fatigue strength are also introduced in this thesis. The main factors causing steel bridge fatigue and the fatigue damage cumulative rules are analyzed 。Secondly, on the basis of introducing the fatigue strength of welding joint, the main factors causing welded structure fatigue are analyzed and the methods for improving contained structure's fatigue strength are introduced.At last, benefit from the research results of home and abroad, the structure fatigue property is analyzed by the model fatigue test. Based on these, stress of it iscalculated by the finite element software. According to comparing an analyzing the test results and theory results, it is proved that the connections of integral joint and track cross beam of Chongqing Caiyuanba Yangtze Bridge is reliable.