Research On The Fatigue Properties Of Old Riveted Steel Bridges

In China, the number of riveted steel bridges which is used for more than50years isabove10thousands. Loads and speeds on both road and railway bridges have increased due tothe development of the economic. The fatigue problem has emerged in a large number of oldriveted steel bridges. In order to use the bridges safely while make the largest economicbenefit, it is necessary to carry out some research on the remaining life and the safety useevaluation system for old riveted steel bridges. Fatigue tests on riveted joints and research onthe fatigue strength of riveted details using a lot of fatigue test results are conducted in thisthesis. In this thesis, the main works are presented as follows:Firstly, Zhongshan Bridge in Lanzhou, an old riveted steel bridge served more than onehundred years, is taken as an object. Tensile fatigue tests are conducted to ensure the fatiguetest data of the specimens with empty holes which were cut from Zhongshan Bridge. In orderto ensure the fatigue strength of specimens with middle plates in two-shear rivetedconnections, a series of tensile fatigue tests of riveted joints which were cut from an oldriveted railway steel bridge under the charge of Xi’an railway station are conducted. Thefatigue test data on riveted steel bridge members and components are integrated，and thespecification of AASHTO and Eurocode are used to evaluate the fatigue details category ofriveted joints.Secondly, the present situation of fatigue assessment of riveted details is concluded andsummarized. The major factors that influence the fatigue strength of riveted details areanalyzed. Riveted details can be divided into five types, include plate with holes, simple shearconnection, riveted steel beam which use the connections between web plates, flange anglesor flange and angles, and riveted truss girder. The test results of different stress ratio aretransformed into that results, stress ratio R=0, using DB RL805. Linear fit the test data by themethod of least squares, the specific value of m and fatigue strength for different fatiguedesign curve for riveted details is ascertained.Research indicates that the common standard fatigue design curve to estimate the fatiguelife of riveted details is not reasonable. Different fatigue design curve for riveted details needto ensure the specific value of m and fatigue strength.