In app L, Prob L-2.1 Solution, formulas used to include stress imposed due to static head and wind load are given. In which subsection or appendix it is given in detail? In app L, only formula given without any detail.
The formulas are strength of materials calculations. The column is essentially treated as a beam. Appendix L has been removed from the Code. I suggest reading PTB-4 for example problems. The examples are much more clear.