ABSTRACT
This paper presents results from a series of ThreeDimensional (3D) finite element analyses of different 5 × 5 pile-raft systems installed in soft clay beds subjected to a set of three far-field ground motions. As Figure 1 shows, the reference ground motion has a duration of about 25 s and peak acceleration of 0.06 g, which may be experienced in Singapore due to a typical far-field earthquake arising from the strike-slip Great Sumatran Fault about 350 km away. To study the effect of different earthquake intensity, the 0.06 g ground motion was further scaled up and down to obtain two more motions with different peak accelerations. For convenience, these 0.01 g, 0.06 g and 0.13 g ground motions are respectively named as “small”, “medium” and “large” ground motions. These ground motions were applied at the base of the numerical model, and the peak acceleration of the excited ground motion was termed “Peak Base Acceleration (PBA)”. The influence of pile flexural rigidity on the raft acceleration and pile bending moment responses were also taken into consideration by varying the Young's modulus of the pile. In addition, in order to investigate the influence of pile head fixity on the raft acceleration and pile bending moment responses subjected to seismic loading, both fixed-and hinged-head piles were considered in the numerical simulations. As listed in Table 1, a total of 24 calculations were performed in this study.
