Abstract：A semi-analytical and semi-numerical method，which makes use of compatible analysis of force and displacement between beams，slab and ground，is developed to analyze interaction between stiffened raft and subsoil by considering the stiffened plate as a composite system of grillage beams and slab. The result converges well and has credible precision. Numerical examples prove that this method has good validity and practicality. Compared with plate raft，stiffened raft has evident advantages in diminishing nonuniform settlement，improving the internal force distribution of raft and reducing construction cost.
