The structure shown in Fig. $4$a required tall slender columns at the left side. It is fully braced by

shear walls on the right. All columns are $4040cm$ as shown in Fig. $4$ b$,$ and all beams are $6015$

$cm$ with $15cm$ monolithic floor slab, as in Fig. $4$c$.$ Trial calculations call for column reinforcement

as shown. Alternate load analysis indicates the critical condition with column AB bent in single

curvature, and service load axial force and moments as follows:

From dead load, $P=620kN,M_{\text{t}\text{o}\text{p}}=82kN-m,M_{\text{b}\text{o}\text{t}\text{t}\text{o}\text{m}}=55kN-m$

From live load, $P=414kN,M_{\text{t}\text{o}\text{p}}=55kN-m,M_{\text{b}\text{o}\text{t}\text{t}\text{o}\text{m}}=36kN-m$

Material strengths are $f_c^{\text{'}}=28$MPa and $f_y=420$MPa. Is the proposed column in Fig. $4$b

satisfactory for this load condition? Use equation as the following to approximate $EI$ for column,

$(EI{)}_{\text{e}\text{f}\text{f}}=\frac{0\mathrm{.}2E_c{I}_g+E_s{I}_{se}}{1+{}_{dns}}$