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PROBLEMS (10.125 through *10.128) An overhanging beam is loaded as shown in Fig.
P10.125 through P10.128. Determine:
(a) The slope at B.
(b) The deflection at point C.
SOLUTION (10.125)
A
2a
M0/2a
M0
B a
C
M0/2a
a/2
M/EI
A2
A1
M0/EI
x
5a/3
C
y
A
θA
tB/A
vC
C’’
x
tC/A C’C’’
C’
M a
M a
1 M0
(2a) = 0
A1 =
A2 = 0
2 EI
EI
EI
M 0 a 5a M 0 a a 13 M 0 a 2
( )+
( )=
tC / A =
6 EI
EI 3
EI 2
2
M a 1
t
M a
2 M 0a
,
t B / A = 0 ( 2a ) =
θA = − B/ A = − 0
3 EI
2a
3EI
EI 3
M 0a
EI
M a M a 4 M 0a
θB = 0 + 0 =
3EI 3 EI
EI
3
(b) We have C ' C " = t B / A = M 0 a 2 EI . Thus,
2
M a2
7 M 0a2
vC = tC / A − C ' C " = 0 (13 − 6) =
↑
6 EI
6 EI
(a) θ B − θ A = A1 =
Continued on next slide
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SOLUTION (10.126)
Beam is symmetric about midspan D, θ D = 0 .
w
w
A
B
2EI
EI
a
a
a
a
wa
wa
M/EI
3a/4
a/2
A1 A
2
2
-wa /4EI
2
-wa /2EI
(a) θ B =
x
Spandrel
a/4 parabola
tB/D
D
A
wa 2
wa 3
a
( )=−
4 EI
4 EI
2
1 wa
wa 3
(a ) = −
A2 = −
3 2 EI
6 EI
θ B = θ B / D = A1
A1 = −
EI
D
tC/D
B
C vC
wa 3
4 EI
a
wa 4
(b) t B / D = A1 ( ) = −
2
8EI
vC = tC / D − t B / D
a
3a
wa 4
tC / D = A1 (a + ) + A2 ( ) = −
2
4
2 EI
4
4
4
wa
wa
3 wa
=−
+
=
↓
2 EI 8EI 8 EI
Continued on next slide
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instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other
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SOLUTION (10.127)
P
P
A
L/2
D
B L/2 C
L/2
RA=0
RB=2P
M/EI
L/6
D
A
A3
-PL/2EI
L/6
M/EI
B
A1
D
A
x
A2
L/3
y
A
PL/EI
- PL/EI
B’
θA
tA/B
D
B
vC
tC/A x
1 PL L PL2
1 PL C
PL2
( L) = −
A1 =
A2 = −
=
2 EI 2 4 EI
2 EI
2 EI
2
1 PL L
PL
L
PL3
A3 = −
t B / A = A3 ( ) = −
=−
2 2 EI 2
8EI
6
48 EI
2
t
PL
θ A = − BA =
L 48EI
AD is a straight line.
(a) θ B / A = θ B − θ A = − A3
θ B = − A3 + θ A =
PL2 PL2
7 PL2
−
=
48EI 8EI 48 EI
L
L
PL3
PL3
t
A
A
(1 − 4) = −
(b) C / A = 1 ( ) + 2 ( ) =
6
3
24 EI
8 EI
3
3
3
PL
PL
3 PL3
vC = tC / A − t B / A = −
+
=
↓
2
8EI 32 EI 32 EI
Continued on next slide
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SOLUTION (*10.128)
w
wa
a
A
3a
B
7wa/6
C
17wa/6
M/EI
17wa2/2EI
A2
A1
-4wa2/EI
B A5
x
A3
-wa2/EI
3a/2
2a
M/EI
9a/4
A A
4
2
-9wa /2
x
B
θA
Spandrel
parabola
A
tangent at A
B
C’’
tB/A C
vC
C’C
C’
1 17 wa 2
51wa 3
wa 2
3wa 3
)3a =
(3a) = −
A1 = (
A2 = −
2 2 EI
4 EI
EI
EI
2
3
2
1 3wa
9wa
1 9wa
9wa 3
(3a) = −
(3a) = −
A3 = −
A4 = −
2 EI
2 EI
3 2 EI
2 EI
2
3
1 wa
wa
(a) = −
A5 = −
2 EI
2 EI
3a
9a
t B / A = A1 (2a) + A2 ( ) + A3 (2a ) + A4 ( )
2
4
4
4
4
4
51wa 9 wa 9 wa 81wa 15wa 4
=
−
−
−
=
2 EI
2 EI
8 EI
8EI
EI
3
1
5 wa
θ A = − tB / A =
3a
8 EI
(a) θ B / A = θ B − θ A = A1 + A2 + A3 + A4 =
θB =
3wa 3
4 EI
3wa 3 5wa 3 1 wa 3
−
=
4 EI
8 EI 8 EI
Continued on next slide
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instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other
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5a
13a
2a
) + A3 (3a) + A4 (
) + A5 ( )
2
4
3
4
4
wa 153 15 27 117 1
55 wa
(
=
− − −
− )=
2 2
8 3
24 EI
EI 4
Then,
4
vC = −C ' C "+ tC / A = − t B / A + tC / A
3
4
4 15wa
55wa 4
5 wa 4
)+
=− (
=
↓
3 8 EI
24 EI
24 EI
(b) tC / A = A1 (3a) + A2 (
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