I agree. ACI 360, "Design of Slabs on Ground" would be your best resource. Typically, your construction joint spacing is dependent on multiple variable such as Subgrade modulus (k), Loading (such a uniform, wall, post or wheel), dowel size and spacing, and the slab's temperature range. For a...
ACI 318 “Building Code Requirements for Structural Concrete,” ANSI/ASCE 3 “Standard for the Structural Design of Composite Slabs,” and SDI #30 “Design Manual for Composite Decks, Form Decks, and Roof Decks” do not require the use of contraction joints for elevated structural slabs.
However...
Assuming a short column, the CRSI "Universal Column Formulas" from the CRSI Design Handbook, 8th Edition (1996) are the best design for bi-axial bending and axial load with load factors from ACI 318 Section 9.2 or Appendix C.
Using the Bresler Load Contour Interaction Equation:
S.R. =...