foundation concrete slab - dilatation yes/no?

[n3jc]

Greetings

Contractor wants me to make this foundation slab (residental building) in one piece since he is worried about differential settlements. He also wants outer (smaller) part of the foundation slab to be only 200 mm thick. I do not like any of the proposed solutions. If I make this in one piece I'd make it 300 mm thick across the whole area (avoiding reinf. detailing problems). Thoughts?

Due to the height difference of the terrain there is also edge beam that in my opinion has to be designed as retaining wall since it will be made first.

 

[r13]

You can use 200mm for the interior slab, with edge (turn down) thickened to 300mm.

 

[BAretired]

If there is a possibility of differential settlement, the exterior slab should be free to rotate relative to the interior slab. It should slope away from the building and should be a little lower than the interior slab where the two slabs meet, in order to prevent the ingress of water into the interior space after a rainfall.



BA

 

[r13]

Provide flexible separation joint between the interior slab and the patio, and lower the exterior slab as mentioned by BA.