260 7 The Force Method
7.2.A clamped-pinned beam is subjected to coupleM 0 at the roller support
B(Fig.P7.2). Find the reaction of supports and construct the bending moment
diagram.
lM 0
A B
MA RA RBFig. P7.2
Ans:MAD0:5M 0 I RADRBD3
2M 0
l7.3.Fixed-pinned beam is subjected to concentrated forceP at the midspan
(Fig.P7.3). Find the reaction of supports and construct the bending moment di-
agram.
lA BP 0.5lC
MA
RA RBFig. P7.3
Ans:MAD3
16PlI MCD5
32PlI RBD5
16P.7.4.The beamABwith clamped supportAand elastic supportBis subjected to uni-
formly distributed loadq; the stiffness coefficient of elastic support isk(Fig.P7.4).
The deflectionof supportB, reactionRBof this support and stiffness coefficientk
are related asDRB=k. Determine the reaction of supports. Consider two special
cases:kD/,kD 0.
Aq
B
k
llFig. P7.4
Ans:RBD3
8ql1
1 C ̨; ̨D3 EI
kl^3