| In this thesis, based on The Chongqing Chaotianmen Yangtze Bridge, the fatigue property about bolt-connected of truss steel bridge connection joint is studied by the method combining theory analysis with model test.First, some basic conceptions of steel bridge fatigue are introduced in this thesis. According to the method of fatigue of BS5400 and ASSHTO bridge design specification and JTJ 025-86 of China, thinking of the actual situation of The Chongqing Chaotianmen Yangtze Bridge, the course of internal force in bridge connection joint is calculated, and then the test load is confirmed with liner linear fatigue damage cumulative rule. Base on the similarity theory that the factor of stress and restriction is nearly as same as the actual bridge and the finite element analysis, not only the test model is designed but also the test method is affirmed. The analysis and evaluation of test data indicate that the values of the main region is very close and shows the linear relation between strain and load, and the second, all the load and unload course, actual strain is symmetrical and that the crack is always not found in the structure of the test panel point. So the conclusion that it can not appear fatigue cracks during design life period with normal periodic maintenance is provided. For predicting the probable service life of the test connection joint of The Chongqing Chaotianmen Yangtze Bridge, the fatigue model test worked under over load beyond design life period is more studied.According to the contrast between the test data and data that the finite element gains, it is validated that the test data which can act as the proof to the true stress situation is exact. Further, it is proved that the connection joint is reliable owing to some correlative knowledge and standards and the existing achievements. It is concluded that the fatigue intensity of the connection joint of The Chongqing Chaotianmen Yangtze Bridge approve to design requirement.
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