Abstract:For the needs of application of steel reinforced concrete (SRC) girders in high speed railway stations, both static and 2 million-cycle fatigue tests on three H-section steel reinforced concrete girders with the same dimension and constructional detail as that of a real engineering project were carried out under design loading. After that, further fatigue tests continued with higher loading than the design loading. The specimens, applied loading and testing program as well as experimental results are presented. The structural behavior under static and fatigue loading is compared. The failure feature of SRC girders about fatigue crack initiation and propagation is described. The current investigation indicated that the SRC girders kept in good condition and at the stage of elasticity when they were subjected to design static loading and 2 million-cycle fatigue loading. The concrete surface crack developed did not exceed 0.2 mm. Fatigue failure occurred after these girders were applied higher-level loading and endured from 0.31 to 1.46 million cycles. Before the fatigue failure, all components in the SRC girders were able to collaborate well and their strain distribution was in agreement with an assumption of plane cross section. The fatigue failure initiated from welded connection between a flange and a web in H-section steel. The fatigue behavior of the welded H-section steel beam played a key role in the fatigue strength of SRC girders. The suggestions for improving the fatigue strength of the SRC girders and future research work are recommended finally.
