Experiment Study on Fatigue Behavior of Steel Reinforced Concrete Girders at High-speed Railway Stations

For the sake of the application of steel reinforced concrete(SRC) girders to high speed railway stations,the static and 2 million-cycle fatigue tests were carried out on three H-section steel reinforced concrete girders with the same dimension and constructional detail as those of an engineering project under the designed loading.Subsequently,some further fatigue tests were carried out under the higher loadings,and the specimens,loading and testing program as well as the experiment results were preseated accordingly.A comparative study was also made of structural behavior under static and fatigue loading.The failure feature of SRC girders about fatigue crack initiation and propagation was described.Experiment study results show that the SRC girders remains in good condition and at the stage of elasticity when they are tested with the designed static loading and 2 million-cycle fatigue loading.The concrete surface crack develops within 0.2 mm.Fatigue failure occurs when higher loadings and another 0.31 to 1.46 million cycles being applied to the girders.Before the fatigue failure,all components of the SRC girders collaborate well and their strain distribution agree well with the assumption of plane cross section.The fatigue failure initiates from the welded connection between a flange and a web of the H-section steel.The fatigue behavior of the welded H-section steel beam plays a key role in the fatigue strength of SRC girders.The proposals for improving the fatigue strength of SRC girders and future research works are put forword finally.