What is the minimum diameter for vertical bars in a column according to ACI?

What is the minimum for vertical bars in a column according to ACI and I am looking for a particular condition where diameter must be greater than 0.625 in. (when using S-concrete for column design it gives a warning that diameter must be 0.625 in. but I couldn't find anywhere in the ACI that include this condition)

If any article or in any clause in ACI refer to this condition please share.

• What is ACI? you should define it or it will be difficult to understand your question. May 2 '17 at 20:28
• @MrYouMath, ACI is the American Concrete Institute. It's a pretty standard acronym in structural engineering. I'm a Brazilian and I know of it.
– Wasabi
May 2 '17 at 20:35
• I'm not an expert on ACI, but codes frequently have limits like "diameter must be greater/smaller than X% of the column's biggest/smallest dimension." What are your column dimensions?
– Wasabi
May 2 '17 at 20:37
• The Brazilian code, for instance, defines that vertical rebar must be $\phi\geq10\text{ mm} \approx 0.4\text{ in}$ and $\phi\leq w/8$, where $w$ is the column's smallest dimension.
– Wasabi
May 2 '17 at 20:41
• @Wasabi In my opinion using acronyms without further explanation is not a good practice. I believe that there are many people on ESE who don't or didn't know this acronym including myself. May 2 '17 at 21:21