Final answer:
While there is no one-size-fits-all answer for reinforced column spacing in a 12" thick wall, a typical maximum spacing might be around 3 to 4 feet on center, with actual spacing depending on specific design requirements and practices.
Step-by-step explanation:
Typically, reinforced columns in a 12" thick wall will be spaced according to specific design requirements, which take into account the structure's intended use, the loads it will carry, and the properties of the materials used. However, there is no universally fixed spacing for reinforced columns.
A common practice often referenced in engineering involves using a multiple of the column's diameter to determine spacing.
Beth's reference to general proportions in building design mentioning that "the columns on the edges are slightly closer to one another than the columns in the center" suggests that not all columns are spaced equally. This might correspond to the older rule of thumb that she mentioned, which was 5 side-to-side and 7-8 deep, implying 5 and 7 to 8 column diameters, respectively.
Newer recommendations suggest spacing as much as 8 diameters side-to-side and 15 diameters deep.
Using this information in the context of the column spacing within a 12" wall, and noting that the question specifies common maximum spacings rather than exact calculations, you might expect a typical maximum spacing to be around 3 to 4 feet on center for small to medium-sized columns typical in many buildings.