Dear sir,
Advice request about suitable foundation/ building type: apartment G +5 levels (story) for the following soil conditions:

Sandy soil up to 7 meters "N" value 3 to 5. From 7 to 25 meters soft expansive marine clay "N" value 0 to 1 Suggest suitable foundation

Or choose one of the following type: Depth of the foundation 2.5 feet from ground level, 1) Isolated footing interconnected at bottom 2) Isolated

Footing interconnected at ground level, 3) Strip foundation (Ribbed raft) with voids in between footings. Depth of the foundation 6 feet, 1) Isolated

Footing (Elephant footing), 2) Isolated footing interconnected at ground level,3)Isolated footing interconnected at bottom -6 feet.