Consider FBD of top most beam as shown in fig (b) and (c)
∑H = 0 RDH = 0 ...(i)
∑V = 0
RC + RDV – 15 – 22.5 = 0
RC + RDV = 37.5KN .....(ii)
Taking moment about point C:
∑MC = 15 × 2.5 + 22.5 × 3.33 – RDV × 7 = 0
RDV = 16.07KN
From equation (ii)
RC = 21.43KN ...(iii)
Consider FBD of bottom beam as shown in fig(d)
∑H = 0
RBH = 0
∑V = 0
RA + RBV – RC = 0
RA + RBV = 21.43KN .........(iv)
Taking moment about point A
∑MA = RC × 2 – RBV × 5 = 0
RBV = 8.57KN
From equation (iv)
RA = 12.86KN.
