x$1=209$mm

x$2=198$mm

x$3=250\mathrm{.}5$mm

A plate girder is fabricated by welding three plates and the dimensions as shown the figure. The girder has a $20$ m span and is simply supported at the two ends. A $w\frac{kN}{m}$ uniformly distributed load is applied on the girder.

Solve the following questions:

a$)$ Find the neutral axis of the girder.

b$)$ Calculate the second moment of area of the girder.

c$)$ If the maximum shear flow on each side of the top flange$-$web connection is equal to $0\mathrm{.}85k\frac{N}{m}m,$ calculate the maximum load, $w$ which can be applied on the girder.