Behavior of Raft Foundation Built on Layered Soil under Different Earthquake Excitation

Achieving the stability of buildings and facilities against any external influence, such as winds, storms, or earthquakes, depends primarily on the foundations supporting them, which are responsible for transferring those loads to the soil layers beneath them.  Accordingly, the design of the foundations to be safe withstand these static and dynamic loads without causing dangers or failures on these structures has recently become the focus of the attention of many researchers. The task of this paper is to predict the behavior of shallow raft foundations supporting loads of structures under the influence of earthquakes in Baquba city and what results from them from downfall and displacement risks. To simulate the soilfoundation model for the study, numerical modeling was used depending finite element approach. Different thickness of raft foundation under different earthquake acceleration-time records that simulate with a Linear Elastic model (LE) built on layered soil represented by Mohr-Coulomb model (MC). The results from this analysis showed properties of soil are used for this study play a vital role in the ground response to the propagation waves. Also observed from the results that an increase in both lateral and vertical displacement as the duration of earthquake increases and raft thickness decreases, but these displacements decreased when the thickness of raft foundation increased from 0.8m to 1.6m are about 9% and 68%, respectively.