Evaluation of dynamic response of connected and non-connected piled raft systems using shaking table tests

Abstract

Regarding the inadequacy of quantitative measurements of geotechnical aspects for assessing the behavior of the piled raft with different head connections during seismic events, A series of shaking table tests modeling, including un-piled-raft foundation, connected and non-connected piled-raft systems with 4 piles and dry sand were conducted. The efficiency of pile head separation and the material of the interposed layer between pile and cap for reducing the bending moment along with the piles length under different excitation scenarios were investigated by imposing base shaking levels with PGAs that ranged between 0.1 to 0.4 g, simulating weak to strong ground motions. Moreover, a comprehensive study is conducted on seismic ground motion amplification patterns induced by piled-raft systems in the soil body and caps as well as lateral raft movements.Based on the shaking table results, the non-connectivity between piles and caps decreased the maximum bending moment of piles by 20–60%, based on input motion amplitudes and cushion layer material. The dependency of both mechanism and amplitude of amplification on the level of base shaking and pile-raft connection details are also revealed.