03-22-2019, 12:47 PM
(03-22-2019, 10:05 AM)megabytephreak Wrote: They did similar at Circa up in Waterloo. This is just a thin layer to start and all of the rebar for the actual foundation will go on top and get poured later. I think it is mostly to make it easier to work on. No equipment getting stuck in the mud etc.
I speculate that it is at least in part to provide a more stable base for the thicker and heavier pour that will come later. In effect, using a layer of concrete, rather than soil, as the bottom of the form for the footings. I recall seeing something similar with some of the supports for the EIT at UW — they would roughly pour a thin layer of concrete, then build nice neat square formwork on top, fill it with a grid of rebar, then then pour it full of concrete. My idea is that pouring directly on dirt would have the danger of slight shifting during setting, leading to lower strength.
Would love to have the opportunity to ask a big-building foundation expert about this!