A comparative analysis of a deep foundation of a highrise building in Bangkok subsoil shows that adoption of the piled raft design concept could result in a significant cost saving of the foundation work. When the raft was placed in the first stiff clay layer, the load share by piles was reduced to 77% from 100% generally considered in the traditional practice. The required number of piles could be significantly reduced without scarifying stability of the foundation and settlement requirement for the building. The 3D FEM analysis yielded a more realistic settlement condition of raft and load distribution of piles than the conventional plate on spring analysis owing to its direct and complete consideration of soil structure interaction.