Numerical modeling of connected and disconnected piled raft foundation under seismic loading in clayey soil

The disconnected piled raft foundation (DCPRF) is one of the newly introduced type of foundations in geotechnical engineering, which greatly reduces the moment and stress on the pile head. In addition, this type of foundation is an ideal choice in areas with seismic activity due to the presence of cushion material between the raft and the piles. This paper aims to present a numerical model in PLAXIS-3D software to simulate the behavior of the connected piled raft foundations (CPRFs) and DCPRFs with the same number and pattern of the piles, under the influence of seismic loading in clayey soil. The study will depend on the earthquake that struck Iraq in November 2017 in the Halabja region of strength 7.3 on Richter scale with PGA (0.1 g). To verify the results of the proposed numerical model, the settlement calculated from numerical is compared with field measurement for the Messe-Torhaus building in Frankfurt and the difference was 2 %. The horizontal displacement of the raft in the CPRF is less than the horizontal displacement of the raft in the DCPRF during seismic loading by 15 %. The vertical displacement in the DCPRF decreased by 7 % in comparison with the CPRF. For the DCPRF, the bending moment value is approximately equal to zero at the head of the piles, and the maximum bending moment value was in the middle of the pile.