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assalam o alaikum, Dear Seniors, Kindly clarify what is the difference between MAT and FOOTING option in SAFE while defining slab property. Thanks.

I am designing a 2B+G+24 story building. I made the model in Etabs, and ran it, then exported the base reaction to safe for footing design. It has central core walls. When I ran safe (v8), the only version available with the office. It gave me a bearing pressure of about 14 ksf as opposed to allowable of 6 ksf, I increased the thickness from 4 ft to 9 ft gradually but pressure distribution remained same & value only deceased to around 11 ksf. Then I added foundation beams (tied up all columns provided them under all core walls) and assigned line support to them (Kv x width of beam). This run gave me a value of 5.6 ksf bearing pressure which is safe. But I have some questions. I calculated the total area required from total load of the building and its coming out almost equal to the building plot area available. For, punching requirement under single column I at least require a 5.5 ft deep raft thickness. 1. Can I model a raft like this with beams (12" x 72") under all columns (42" x 42") & (36x72") under core walls (24" thick); not inverted beams but beams with top flushed with raft top 3. when we define slab properties do I have to tick the " thick plate" option or not. What is the difference? 4. What is difference between slab types options? slab? footing? mat? 2. Do the slab elements between these beams will have a soil support also assigned to them? 3. Is this type of foundation safe for this high building? or do we have to go for piles or pile/raft interaction? Which would you recommend considering that top of raft is at -19 ft & ground water table is at -11 ft. 4. How to I assign wall supports in safe v8. By placing beams of above property on my raft slab & assigning a wall/line support to them (Kv x width of beam) or Assigning null property to beams and use safe v8 option in which it calculate support stiffness from its size. Kv is the vertical sub-grade modulus. 5. How do we detail thick rafts. Do we provide mid layer of steel. if so can somebody point a reference book or source on how to calculate it. Confused