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sm10 129 130

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PROBLEMS (10.129 and 10.130) A beam ABC with an overhang BC supports a lod as shown in
Figs. P10.129 and P130. Determine:
(a) The angle of rotation at support B.
(b) The deflection at the free end C.
SOLUTION (10.129)
P
A
P/3
C
a
B
3a
4P/3
M/EI
2a
2a/3
x
A2
A1
-Pa/EI
θA
4tA/B/3
tB/A
A
tC/A
vC
B
C
2
1 Pa
3 Pa
1 Pa
Pa 2
(3a) = −
(a ) = −
A2 = −
2 EI
2 EI
2 EI
2 EI
2
3
3
2a
3Pa
Pa
10 Pa
tC / A = A1 (2a ) + A2 ( ) = −
−
=−
3
3EI
3 EI
EI
2
3Pa
t B / A = A1 (a) = −
2 EI
1
Pa 2
θ A = − tB / A =
3a
2 EI
A1 = −
(a) θ A / B = θ A − θ B = A1
θ B = θ A − A1 =
1 Pa 2 3 Pa 2 Pa 2
−
=
2 EI 2 EI
EI
4
10 Pa 3 4 3Pa 3
)
− (−
(b) vC = tC / A − t B / A = −
3
3 EI 3
2 EI
4 Pa 3
=
↓
3 EI
Continued on next slide
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SOLUTION (10.130)
w
A
2a
a
B
C
M/EI
Parabola
wa2/2EI
A1
A2
x
A3
Spandrel
parabola
-wa2/2EI
y
tangent at B
tB/A
θB
B
θB
A
C’’
C’
C
vC
tC/B
2
wa 2 2 wa 3
A1 = − (2a )
=
3
2 EI 3 EI
1 wa 2
wa 3
1 wa 2
wa 3
(2a) = −
(a ) = −
A2 = −
A3 = −
2 2 EI
2 EI
3 2 EI
6 EI
4
4
4a
2 wa 4 wa
t A / B = A1 (a) + A2 ( ) = −
−
=0
3
3EI
6 EI
(a) θ B =
1
t A / B = 0 Thus C ' C " = 0 .
2a
3a
wa 4
(b) tC / B = A3 ( ) = −
4
8 EI
4
wa
vC = tC / B =
↓
8EI
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or
instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other
reproduction or translation of this work beyond that permitted by Sections 107 or 108 of the 1976 United States
Copyright Act without the permission of the copyright owner is unlawful.
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