Effects of Site Factors on the Performance of Rigid-Pile Composite Foundation in Tall Buildings

Abstract

Values of site factors in numerical simulation can have profound effects on the calculation accuracy. In order to fully understand the performance of rigid-pile composite foundation in tall buildings, this article set up an overall FEA model of a 25-storey frame-tube structure by considering the interaction of superstructure, foundation and ground. Thereafter, a detailed parametric study was performed by changing values of different key site factors. These parameters include: Ground soil range, distance of neighboring buildings and deformation modulus of cushion. The results show that 1) Ground soil range has a great influence on the stress and settlement of raft, the effective influence range is 2-3 times of the raft dimension; 2) Influence of neighboring buildings on the stress and settlement of the raft can be neglected; 3) With the increase of cushion modulus, the raft stress increases while the settlement decreases, an optimal cushion modulus is recommended to be 20-40MPa.

Model Test on the Vibration Reduction Characteristics of a Composite Foundation with Gravel Cushion under Different Seismic Wave Amplitudes

“…Research on the seismic isolation effect of a gravel cushion is still in the stage of theoretical analysis and laboratory investigation. Han et al [16,17] discovered that the thicknesses of gravel cushions was positively proportional to the seismic isolation performance and that a gravel cushion with a thickness range of 0.2 to 0.3 m could reduce the acceleration by 10 to 15%. Using the discrete element method, Zhao et al [18] comparatively investigated the seismic isolation effect of gravel cushions of different thicknesses on the superstructure at different foundation base pressures.…”