Question 3.28: Determine the support reactions of a simply supported beam c...

Considering FBD of crane and beam as shown, in Fig. 3.39 (a)
Considering equilibrium of crane,

R_{C}+R_{D}=6  KN                                                      ….. (1)

R_{D}=4.5  KN

Substituting the value of R_{D}  in equation (1),

R_{C}=6-R_{D}=6-4.5

R_{C}=1.5  KN

Considering equilibrium of beam AB

\sum Y=0, \qquad R_{A}+R_{B}=R_{C}+R_{D}

=1.5+4.5=6  kN

\sum M_{A}=0, \qquad R_{B} \times 9=1.5 \times 3+4.5 \times 5

= 27

R_{B}=3  kN

R_{A}=3  kN