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Thank you very much for your reply. I have rechecked my Etabs model & tried different shear wall configurations and then checked the raft on safe (flat slab with drop panels, beams were confusing me). My base pressure results remain in the range from 7 to 10 ksf. Then a senior in my office told me to draw a layer of lean concrete under my raft plate, slightly bigger than it, with 6" thick & no design. The draw my raft slab, over it, then my drop panel or thickened sections over it. Select all 3 slab properties & assign soil support to them. Pick up column points, right click & assign column sizes to the loads. And my base pressur comes down to 4.5 ksf. I can understand the logic of assigning soil support to all 3 as they are overlapping each & sfae will take then which is uppermost & thicker, so assign soil support to all. Next by providing column sizes we are ensuring that safe take into account the rigid zone for column in base pressure, punching & bending. But what is the logic of providing the lean layer? How does it control the base pressure? Second can we ignore the reinforcement peaks in slab strips under column & core wall edge points? When I calculate reinforcement from strip moments manually the value is much lower than the one reported. How to resolve this?