###### Abstract  
Integral abtment bridges (IABs) have been widely applied in bridge engineering because of their excellent seismic performance, long service life, and low maintenance cost. The superstructure and substructure of an IAB are integrally connected to reduce the possibility of collapse or girders falling during an earthquake. The soil behind the abtment can provide a damping effect to reduce the deformation of the structure under a seismic load. Girders have not been considered in some of the existing published experimental tests on integral abtment-reinforced-concrete (RC) pile (IAP)-soil systems, which may not accurately represent real conditions. A pseudo-static low-cycle test on a girder-integral abtment-RC pile (GIAP)-soil system was conducted for an IAB in China. The experiment's results for the GIAP specimen were compared with those of the IAP specimen, including the failure mode, hysteretic curve, energy dissipation capacity, skeleton curve, stiffness degradation, and displacement ductility. The test results indicate that the failure modes of both specimens were different. For the IAP specimen, the pile cracked at a displacement of +2 mm, while the abtment did not crack during the test. For the GIAP specimen, the pile cracked at a displacement of \(-\)8 mm, and the abtment cracked at a displacement of 50 mm. The failure mode of the specimen changed from severe damage to the pile top under a small displacement to damage to both the abtment and pile top under a large displacement. Compared with the IAP specimen, the initial stiffness under positive horizontal displacement (39.2%), residual force accumulation (22.6%), residual deformation (12.6%), range of the elastoplastic stage in the skeleton curve, and stiffness degradation of the GIAP specimen were smaller; however, the initial stiffness under negative horizontal displacement (112.6%), displacement ductility coefficient (67.2%), average equivalent viscous damping ratio (30.8%), yield load (20.4%), ultimate load (7.8%), and range of the elastic stage in the skeleton curve of the GIAP specimen were larger. In summary, the seismic performance of the GIAP-soil system was better than that of the IAP-soil system. Therefore, to accurately reflect the seismic performance of GIAP-soil systems in IABs, it is suggested to consider the influence of the girder. b 2024 1 10166 10.3390/app142210166 10.  
driving experience, reduced noise, excellent overall integrity and durability, and minimal maintenance requirements [5; 6; 7]. Bridges can be damaged during earthquakes, leading to significant economic losses and risks to human safety. The seismic response of IABs can be reduced significantly because the superstructures of IABs are effectively constrained by the abutments, backfill, piles, and surrounding soil [8; 9; 10; 11]. Under seismic loads, the substantial horizontal cyclic displacements of the girders in IABs can be transmitted to the abutments and the piles beneath them to create complex girder-abutment-pile-soil interactions [12; 13; 14]. The greater the stiffness of the abutments and piles, the greater their constraint on the horizontal cyclic displacement of the girders, and the larger the internal forces of the structure [15]. When the abutments and piles cannot sufficiently absorb the horizontal deformation, the abutments and piles may crack under small horizontal cyclic displacements [11; 16; 17]. Field monitoring measurements [18; 19; 20], finite element analyses [8; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28], theoretical research [29; 30; 31; 32], and experimental tests [33; 34; 35; 36] have been used to study the seismic performance of IABs. In References [8; 19; 30; 31; 32], the seismic performance of IABs was investigated by considering the whole bridge with the soil-structure interactions. It has been found that under seismic loading the nonlinear effects and stress from the soil increase.