solid slab raft foundation

1. The ground must be at least 50mm thick , and the center must be put a insulation and the second lower layar is 150mm reinforcement concrete with damp proof membrane , the last 1 is 50mm blinding concrete
2. The effect of the load from columns and the ground pressure is to create areas of tension under the columns and areas of tension in the upper part of the raft between the columns ,
3. Thus , the concrete raft is reinforced top and bottom against both upward and downward bending ,
4. A nominal mesh of reinforcement is provided in the faces where tensuon deos not occur to control shrinkage cracking of the concrete