Since there is composite beam, there fore first consider top most beam,
Let reaction at A is RAH and RAV
Reaction at B is RBV
Reaction at C is RAV
Reaction at D is RDH and RDV
Draw the FBD of Top beam as shown in fig (b)
∑H = 0
RAH = 0
∑V = 0
RAV + RBV – 80 = 0
RAV + RBV = 80KN ........(i)
Taking moment about point A:
∑MA = 80 × 3 – RBV × 4 = 0
RBV = 60KN
From (i), RAV = 20KN
Consider the FBD of bottom beam as shown in fig (c)
∑H = 0
RDH = 0
∑V = 0
RCV + RDV – RBV = 0
RCV + RDV = 60KN ........(ii)
Taking moment about point D:
∑MD = –60 × 4.5 + RCV × 4 = 0
RCV = 67.5KN
From (ii), RDV = –7.5KN.
