Experimental and numerical studies on the proposed stiffener detailing of integral bridge steel H piles to alleviate the combined adverse effects of axial load and cyclic thermal displacements

Past research studies demonstrated that local buckling may be observed when the steel H piles (SHPs) at the abutments of integral bridges are simultaneously subjected to axial load and lateral plastic displacements. The large curvatures and strains associated with local buckling may lead to earlier low cycle fatigue (LCF) failure of the pile under cyclic thermal displacements. Accordingly, first, the detrimental effect of axial load combined with lateral plastic displacements leading to local buckling and accelerated LCF failure of the SHP is demonstrated through experimental testing and finite element modeling and analysis. Then preventive measures to eliminate or delay local buckling are developed and assessed numerically as well as by experimental testing. Numerical simulation and experimental test results revealed that welding longitudinal stiffeners on the flanges successfully prevent the local buckling of the flanges and improve the fatigue life of the pile.