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Extracted text: A building has to be supported over a raft foundation of dimensions 15 m x 25 m. The soil is clay having unconfined compressive strength of 20 kN/m?. The safe pressure to be applied at the base of raft is 180 kN/m2. The building has provision of basement floors, then = 19 kN/m3. Adopt recommend the depth of raft foundation. Use FOS = 3.0 and unit weight of clay Skempton's approach.