In footings many engineers tend to ignore this minimum steel ratio bw x d x 200/fy . Does ACI or any thing relevant confirms this anywhere. Thanks in advance.
You can only ignore it if 4/3 of the required steel is less than T&S steel. ACI says that if your required stee; ratio is below the minimum steel ratio you can get around the 0.0033 minimum by increasing by 1/3.. If, however, you increase it by 1/3 and you are still below the minimum As for T&S you MUST use the minimum for T&S which is 0.0018bh.
In ACI-318, Section 10.5.1 gives that as the As,min for "flexural members". Section 10.5.4, three paragraphs down, gives As,min for "structural slabs and footings of uniform thickness" as that required by 7.12.
