Seismic response analysis of high-rise frame-core tube building on fluid-saturated soil considering soil-pile-structure interaction

This paper proposed a three-dimensional (3D) refined finite element method (FEM) to determine seismic responses of the high-rise buildings resting on fluid-saturated soil considering the soil -pile-structure interaction (SPSI) and the dynamic characteristics of two-phase media, using a user-defined element with ABAQUS. The theory and method to develop the FEM were introduced in detail, including the user-defined element, material constitutive models, boundary conditions, earthquake input methods, specific implementation procedures, and verifications. Then, the FEM was adopted to investigate the seismic responses of a 51-story high-rise building with a frame -core tube system subjected to six earthquake records. Discussions were conducted on the accel-eration, displacements, inter-story drifts, story shear force, and damage behavior to interpret the seismic characteristics of the superstructure. A fixed-base model was also considered to reveal the SPSI effect under the same conditions. The results demonstrate that the SPSI lightens acceleration and total story shear force but amplifies displacements, inter-story drifts, and column shear force. Without regard to the SPSI, no apparent change appears for the damage of floor plates, whereas the core tube suffers more severe damage than under the SPSI conditions. For high-rise buildings, the SPSI does not always provide conservative seismic performance evaluations. It is of funda-mental importance to include the SPSI effect during the performance-based seismic design of high-rise buildings for comprehensive understanding. The proposed FEM can also be access to seismic SSI analysis for other types of structures in the saturated field.