Research on Seismic Response and Damage Characteristics of Soil–Pile–Frame Structures Based on a Three-Dimensional Numerical Simulation

Frame structures are important forms of building structures but are prone to damage under earthquake action. In regions with complex geological conditions, it is particularly crucial to consider the soil–foundation–structure interaction under seismic action. Based on the concrete damage plasticity (CDP) model, this study establishes a three-dimensional numerical model of the soil–pile–frame structure and investigates its seismic response by inputting Northridge and Taft waves. The results show that the growth of floor peak acceleration slows down with increasing height (showing a quadratic function change), and the fluctuation is greater under the action of Taft waves; the floor peak displacement increases with the increase of height, with more significant growth under the action of Northridge waves; the pile shaft displacement gradually increases from the bottom to the top, and the displacement change at the soil layer interface is affected by soil properties, while the peak bending moment at the pile top under the action of Taft waves is higher; the damage characteristic analysis results indicate that beam–column joints are weak parts, and the damage process is divided into three stages: “no damage, damage development, and damage stabilization”; and the soil–pile–frame interaction makes the structure present a reasonable “strong-column–weak-beam” failure mode, which is consistent with the actual situation. This study can provide a reference for the seismic design of frame structures in complex geological conditions.