###### Abstract  
Studies on the seismic response of skewed integral abutment bridges have mainly focused on response under far-field non-pulse-type ground motions, yet the large amplitude and long-period velocity pulses in near-fault ground motions might have significant impacts on bridge seismic response. In this study, the nonlinear dynamic response of an skewed integral abutment bridge (SIAB) under near-fault pulse and far-fault non-pulse type ground motions are analyzed considering the soil-structure interaction, along with parametric studies on bridge skew angle and compactness of abutment backfill. For the analyses, three sets of near-fault pulse ground motion records are selected based on the bridge site conditions, and three corresponding far-field non-pulse artificial records are fitted by their acceleration response spectra. The results show that the near-fault pulse type ground motions are generally more destructive than the non-pulse motions on the nonlinear dynamic response of SIABs, but the presence of abutment backfill will mitigate the pulse effects to some extent. Coupling of the longitudinal and transverse displacements as well as rotation of the bridge deck would increase with the skew angle, and so do the internal forces of steel H piles. The influence of the skew angle would be most obvious when the abutment backfill is densely compacted. skewed integral abutment bridges; near-fault ground motions; soil-structure interaction; skew angle; backfill compactness  
24 February 2021  
31 March 2021  
Subsibet: 3 April 2021  
effects, which introduce high seismic energy into structures, and induce large structural deformations and damages [15]. Research has been carried out on the seismic response of various bridge types under near-fault pulse type ground motions. [PERSON] et al. [16] studied the seismic response of a typical three-span continuous highway girder bridge under near-fault strong ground motions, and found that the seismic design spectrum considering near-fault effects significantly intensified bridge seismic response. [PERSON] et al. [17] evaluated the seismic response of a simply supported girder bridge under six sets of near-fault ground motions, considering contact and separation between the girder and abutment in the longitudinal direction, and concluded that the peak bridge response increased as the amplitude and period of the ground motion pulse increased. [PERSON] et al. [18] investigated the seismic response of a long-span asymmetrical suspension bridge subjected to four levels of near-fault ground motions. The results showed that compared to far-field ground motions, the response and power spectrum values were several times higher in the long-period range, and the seismic response of the bridge tower increased significantly under the near-fault ground motions, especially in soft soil. [PERSON] et al. [19] investigated the seismic behavior of a long-span concrete-filled steel tubular arch bridge subjected to near-fault ground motions, and found that the forward-directivity and fling-step effects might induce significantly higher seismic demands and damage to the bridge structure. [PERSON] et al. [20] investigated the seismic behavior of a long-span cable-stayed bridge under near-fault ground motions, which generated larger internal forces and displacements in the bridge. However, until now, almost no research has been published on the seismic response of integral abutment bridges under near-fault pulse-type ground motions. Integral abutment bridges are bridges in which the super-structure is cast monolithically with the abutment, typically supported by a single row of piles to provide the required flexibility for thermal movements [21; 22; 23]. In the United Kingdom the trend is to have the flexible abutment with a double row of piles [24; 25; 26]. Compared to expansion joints and abutment bearings, the integral abutments would facilitate faster and simpler construction, minimum joint corrosion or damage, reduced maintenance costs and increased structural integrity [27; 28; 29].