Solve for all

Starting with the column in Problem $1,$ perform enough additional calculations to determine the effects of increasing $f_c^{\text{'}}$ from $5000$ to $8000$ psi on column capacity at both high and low axial loads. Assuming that a compressive strength of $8000$ psi is appropriate for the lower stories of a high$-$rise structure, would you recommend using concrete with $f_c^{\text{'}}=8000$ psi for the columns supporting all stories within the building? Use your analysis to support your answer.