Pouring a slab on a site with topography is always a challenge, but it is what we do here in Austin. We just got this update from Adrian showing a unique concrete wall he is pouring in preparation to build a home on a significantly-sloping lot (greater than a 30-foot change in elevation from top to bottom).
The vertical wall forms are erected using “wall ties” at various lengths that dictate the thickness of the wall. Here, the wall will change from 15″ thick at the bottom half to 12″ thick from about 5′ up. The black ties are where it is 15″ and the blue are the 12″ areas. After the rebar is installed, plywood with holes evenly spaced will be lined up with the interior side of the wall ties. That will then be clamped in place. Then, with the help of a pump truck, concrete will be placed in the wall forms with another key way in the top to connect it the 3rd stage of concrete.