When load on column is large or when column is subjected to moment along with axial load gusseted base is provided

It consist of base plate gusset plate connecting angle provide on either side of column and web clear angle

Step I Cal required area of base plate

a) Ap=$\frac{Pu}{0.6\ast fck}$

b) width of plate =(Bp)=depth of column+2(If any cover plate)+2$\times$(thickness of gusset plate)+2$\times$(lenght of connecting leg of angle with base slab)+overnage (clearance)

c) Lp=$\frac{Ap}{Bp}$

step II a) thickness of base plate tp= thickness of bse plate equating elastic section modules

Ze=$\frac{bd^{2}}{6}$

consider unit width

Ze=$\frac{1\times t^{2}}{6}$

Zp=$\frac{m\ast \gamma mo}{fy}$

where

m=$\frac{wl^{2}}{2}$ B.m @ face of angle

Ze=$\frac{zp}{s}$

S=$\frac{Zp}{Ze}$ for s--IS page 138

find thickness=?

Step III a) (Ze)p=$\frac{bd^{2}}{6}$

considering unit width

Ze=$\frac{1\times t^{2}}{6}$

b) Zp=$\frac{m\ast \gamma mo}{fy}$

where m=$\frac{wl^{2}}{8}=\frac{wl^{2}}{2}$.... Bm at central portion

Ze=$\frac{Zp}{6}$

find thickness=?

note:- central portion bending in two direction hence the thickness of plate is halved