Question No$.2$

Design a member for the top chord $AB$ in the truss shown in Fig. $2$ using a double $C$ section

back$-$to$-$back. Use G$40\mathrm{.}21-$M$350$W steel. The ends of member AB are welded to $18mm$ gusset

plates. Horizontal bracing is provided at the joints. Assume that the weld length $L$ along both

sides of the channels at ends A and B is $L=1\mathrm{.}25d,$ where $d$ is the depth of the $C$ section. The

service loads are shown in Fig. $2.$

Figure $2$