*For residential building,*
If it is designed as the load-bearing structure you can provide 20cm x20 cm tie columns for more strength. (for good soil)
if you are designing it as a semi-framed structure, you can provide column size of 20 cm x 30 cm.
If it is fully framed structure, provide column size of 20 cm x 40 cm.
Tinu J
Civil Engineer | Ernakulam
*For residential building,* If it is designed as the load-bearing structure you can provide 20cm x20 cm tie columns for more strength. (for good soil) if you are designing it as a semi-framed structure, you can provide column size of 20 cm x 30 cm. If it is fully framed structure, provide column size of 20 cm x 40 cm.
Ullas Udhayan
Civil Engineer | Thrissur
40cm*20cm enough for normal soil.