For the semi$-$circular three$-$pinned arch shown in Fig. Q$1$ with

supports at different levels:

a$)$ Calculate the vertical and horizontal support reactions of

$R_{B,V}$ and $R_{B,H}.$ Then determine the normal force, shear force

and bending moment at point $D.$

The arch is pinned at $A,B$ and $C$ and subjected to concentrated

force of $50kN.$ The vertical distances of A and $B$ to the crown

$($point $C)$ are $8m$ and $6m$ respectively.

Fig. Q$1($Not to scale$).$