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Integral abutment bridges (IABs) are those bridges without expansion joints. A single row of steel H-piles (SHPs) is commonly used at the thin and stub abutments of IABs to form a flexible support system at the bridge ends to accommodate thermal-induced displacement of the bridge. Consequently, as the IAB expands and contracts due to temperature variations, the SHPs supporting the abutments are subjected to cyclic lateral displacements, which may eventually lead to low-cycle fatigue (LCF) failure of the piles. In this study, to obtain the LCF life of SHP commonly used in IABs, fracture mechanics approaches is used. For these purpose, experimental tests are conducted on several SHP specimens to determine their LCF life under thermal-induced cyclic flexural strains. In the experimental tests, the specimens are subjected to lateral displacements (or flexural strain cycles) with various amplitudes in the absence and presence of a typical axial load. Next, the fracture mechanics approach is used only for the prediction of the large strain amplitude, ea that the SHP specimens can sustain before their failure takes place due to LCF effects and compared with the test results. Considering the inherent scatter in fatigue tests, a reasonably good agreement is found between the calculated fatigue lives and those from test results. |
