my figures
a past life. used to have a foot in the construction industry; there are various design guidelines and calculators all over the place; many in print but also a few online. Online tend to be scarce or cryptic, usually because there are so many variations in materials and situations.
In Australia, concrete structures code, AS 3600 governs the design standards for concrete structures. It's all in there, and mostly the laws and regulations will require complying with SA specs or be based on them. FWIW.