Under seismic conditions a bridge abutment can transfer significant inertial effects to the superstructure due to its interaction with a large volume of soil. These effects can lead to a marked dynamic amplification of the abutment response that should be accounted for in bridge design. In order to quantify these effects, we present analytical solutions for the modal characteristics of the soil-abutment system at small strains, expressed in terms of the vibration periods and mass participation factors for the approach embankment considering different directions of motion. The effect of nonlinear soil behaviour is also investigated through nonlinear numerical analyses of the soil-abutment system in OpenSees, which establish the dependence of the vibration periods on the intensity of the external perturbation. The numerical results were used as a benchmark to validate the analytical predictions at small strains; they can also provide some indication on the applicability of the analytical formulation at medium and large strain levels. The proposed method of dynamic identification can be used as a tool to evaluate the dynamic characteristics of bridge abutments, which can be in turn regarded as the inertial features of macroelement representations for abutments in the structural analysis of bridges.

在地震条件下，由于桥台与大量土壤的相互作用，桥台可以将显着的惯性效应传递给上部结构。这些影响会导致桥台响应的显着动态放大，这在桥梁设计中应该考虑在内。为了量化这些影响，我们提出了小应变下土-桥台系统的模态特征的解析解，以考虑不同运动方向的引道路堤的振动周期和质量参与因子表示。非线性土壤行为的影响还通过 OpenSees 中土壤-桥台系统的非线性数值分析进行了研究，确定了振动周期对外部扰动强度的依赖性。数值结果被用作验证小应变分析预测的基准；它们还可以为分析公式在中等和大应变水平下的适用性提供一些指示。所提出的动力识别方法可用作评估桥梁桥台动力特性的工具，而动力特性又可被视为桥梁结构分析中桥台宏观单元表示的惯性特征。