The composite metal $(20$ guage$)$ floor deck of an office is to be supported by the simple

supported trusses shown in Figure $3.$ Each truss is $4\mathrm{.}5$ m long and they are spaced $1\mathrm{.}0$ m on

centers. The floor itself is to be made from lightweight concrete that is $125$ mm thick.

Neglect the weight of the truss. Determine the factored load $(1\mathrm{.}2$DL $+1\mathrm{.}6$LL$)$ that acts on

the truss along gridline D and calculate and draw the bending moment and shear force

diagram. $($Marks $20).$

Light Concrete fill finish $($per mm thickness$)$ is $0\mathrm{.}023k\frac{N}{m^2}$

Office live load is $2\mathrm{.}79k\frac{N}{m^2}$

Deck, metal, $20$gauge $=0\mathrm{.}14k\frac{N}{m^2}$