Soil Interaction of H-shaped Steel-RC Stepped Pile of Integral Abutment Bridge: Experimental Evaluation

Abstract

The reinforced concrete piles (RC) in integral abutment bridges (IABs) are challenging to meet the longitudinal deformation of bridges with significant lateral stiffness. The H-shaped steel (HS) piles are costly and prone to corrosion. This paper proposes a new form of pile comprised of HS and RC piles in series to meet the longitudinal deformation demand of IABs. Tests were conducted for one HS pile under reciprocating low-cycle pseudo-static test and two HS-RC stepped piles with different bending stiffness ratios of HS/RC (0.25 and 0.5) using the HS-RC pile test model,. The influence of the stiffness ratio on the mechanical behavior of stepped pile-soil was studied. The mechanical behavior of the stepped pile was also compared with single HS and RC piles. and the applicability of the m and p-y curve methods to the calculation of horizontal displacement of stepped pile is discussed. The results show that the elastic deformation range of the HS pile is 2 mm to 25 mm, and its horizontal deformation capacity and bearing capacity are excellent. As the stiffness ratio increases, the stepped pile-soil system's yield displacement and yield load increased. The stiffness ratio has no significant effect on the failure mode of the piles. The hysteretic ring of the stepped pile shows a squeezing shape at the initial loading stage, but becomes a full spindle in the later loading stage. The stepped pile shows an excellent energy consumption effect and a horizontal deformation ability, indicating it is suitable for IABs. The m method has better accuracy only up to 2 mm displacement, while the p-y curve method still has higher accuracy within 15 mm.