In this study, we conducted numerical parametric analyses to investigate the seismic performance of a bridge pier with a spread footing on dense sandy ground. For the numerical model, we considered plastic hinging in the pier and foundation rocking, sliding, settlement, and embedment. The investigated parameters included pier height, footing width, excitation intensity and type, and footing embedment. With an increase in the pier height-to-foundation width ratio, the rocking response became more pronounced. The direction of the foundation’s permanent tilt was highly dependent on that of the maximum foundation rotation. Near-fault pulse-like ground motions destabilized a system easily. In addition, the maximum drift ratio of the pier and the maximum rotation and settlement of the footing were highly dependent on the minimum contact area. Thus, the ratio of minimum contact area to footing base area (minimum contact area ratio) is an important index for evaluating the performance and stability of the model. When the minimum contact area ratio exceeded 30%, the overall performance of the pier-footing system was suitable; by contrast, when it was below 30%, the drift ratio of the pier and rotation of footing dramatically increased, influencing the system stability.

在这项研究中，我们进行了数值参数分析，以研究在密集沙地上具有扩展基础的桥墩的抗震性能。对于数值模型，我们考虑了桥墩中的塑性铰以及地基的摇摆、滑动、沉降和嵌入。研究的参数包括桥墩高度、基脚宽度、激发强度和类型以及基脚嵌入。随着墩高与基础宽度比的增加，摇摆响应变得更加明显。基础永久倾斜的方向高度依赖于最大基础旋转的方向。近故障脉冲式地面运动很容易使系统不稳定。此外，桥墩的最大漂移比和基脚的最大旋转和沉降高度依赖于最小接触面积。因此，最小接触面积与基础面积之比（最小接触面积比）是评价模型性能和稳定性的重要指标。当最小接触面积比超过30%时，墩基体系整体性能适宜；相比之下，当低于30%时，桥墩的漂移率和基础的旋转急剧增加，影响了系统的稳定性。