Beam detailing check — required vs provided steel

A validated beam design requires $A_s=1,420\text{ mm}^2$ of bottom reinforcement. The preferred bar diameter is 20 mm. Determine the minimum number of equal bars needed based on steel area alone, then explain what must still be checked before accepting the detail.

Column grouping review

Four 400 mm × 400 mm columns have similar materials and story heights. C1/C2 carry about 1,200 kN axial force with moments near 90 kN·m, while C3/C4 carry about 750 kN with moments near 55 kN·m. Should all four automatically use one reinforcement group?