Solution: 11-1. Determine The Moments at A, B, and C, Then Draw The

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Determine the moments at A, B, and C , then draw the moment diagram or the beam. The moment o inertia o each span is indicated in the igure. Assume the support at B  is a roller and A and C  are   are ixed. E 29(103) ksi. 11–1.

30 k

800 lb>ft



  =

 A

 I   AB 

4

 900 in

5

B  I BC  

24 ft

4

 1200 in

5

8 ft

8 ft

Solution

 

(DF) AB

  =

0 (DF)BA

(DF)BC 

  =

0.6667

(FEM) AB

  =

(FEM)BA

  =

(FEM)BC 

  =

(FEM)CB

  =

 

>

- 0.8(24)2 12

=

>

0.75 I BC  BC  24   +   I BC  BC  16 (DF)CB

 

>

0.75 I BC  BC  24   =

  =

  - 38.4 k # t

38.4 k # t

 -

30(16) 8

 

=

  - 60.0 k # t

60.0 k # t

 

A

Mem.

 

AB AB

BA

BC

CB

0

0.3333

0.6667

0

FEM

 

- 38.4

C

B

38.4   - 0.0 7.20

a M    - 34.8

  =

M BA

  =

M BC  BC 

  =

M CB

  =

  - 34.8 k # t 45.6 k # t

  - 45.6 k # t 67.2 k # t

60.0

14.40

3.60

M  AB

0.3333

0

Joint DF

  =

7.20 45.6   - 45.6

67.2 k # t

Ans. Ans. Ans. Ans.

Ans. M  AB M BA M BC  M CB 5 18

  =

  =

  =

  =

  - 34.8 k # t 45.6 k # t   - 45. k # t 67.2 k # t

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

Determine the moments at B  and C . EI   is constant. Assume B and C  are  are rollers and A and D are pinned. 11–2.

3 k>ft

 A

B

8 ft

C

20 ft

D

8 ft

Solution FEM AB

  =

FEMCD

  =

FEMBA

  =

FEMDC 

  =

FEMBC 

  =

wL2

 -

 

=

wL2 12 wL2 12

  =

DF AB

 

3EI   , 8

  =

1

  =

 

=

  - 16

16

 

K BC 

  =

 

4EI   , 20

wL2   =

 

=

100

12 K CD

  =

3EI    8

  DF DC 

DFBA

  =

DFCD

DFBC 

  =

DFCB

Joint

=

  - 100 FEMCB

12

K  AB

 

 

  =

  =

3EI    8 3EI  4EI      + 8 20 1   - 0. 52

  =

A

0.652

0.348 B

Member   AB

BA

DF 1 FEM   - 16

0.652 16  

Dist.

54.782

16

=

C BC

0.348 - 100

CB

CD

0.348 10 0  

0.652 - 16

8

 

- 14.609

  14 14.609

Dist.

4.310

2.299

- 2.299

  - 1.149

1.149

0.40 0

- 0.400

- 0.200

0.20 0

0.070

- 0.070

CO 0.750

CO Dist.

0.130

  - 0.035

CO Dist.

a M 

0.023 0

84.0

DC  

1   16

29.218   - 29.218   - 54.782   - 1

CO

Dist.

D

0.0 12

 

- 84.0

 

-8   - 4.310   - 0.750   - 0.130

0.035

- 0.012 84.0

 

- 0.023 - 84.0

0 k # t

Ans. Ans. M BA BA M BC  BC  M CB M CD

519

  =

  =

  =

  =

84.0 k # t   - 84.0 k # t 84.0 k # t   - 84.0 k # t

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

Determine the reactions at the supports. Assume  A  is ixed and B and C  are  are rollers that can either push or pull on the beam. EI  is  is constant. 11–3.

12 kN>m

 A

B



5m

2.5 m

Solution Member Stiffness Factor and Distribution Factor. Factor. K  AB

4EI  L AB

  =

(DF) AB

  =

(DF)BC 

  =

(DF)CB

  =

=

4EI  5  

 

0

=

 

0.8EI 

(DF)BA

  =

  =

3EI  LBC 

0.8EI  0.8EI   + 1.2EI 

  =

1.2 EI  0.8EI   + 1.2EI 

K BC  BC 

  =

=

3EI  2.5  

=

1.2EI 

0.4

0.6

1

 Fixed End Moments. Reerring to the table on the inside back cover,

(FEM) AB

  =

(FEM)BA

  =

(FEM)BC 

  =

wL2 12 wL2 12

12(152)  

=

 

=

 

12

=

12(52)

(FEM)CB

12   =

 

=

  - 25 kN # m

25 kN # m

0

Moment Distribution. T  Tabulating abulating the above data,   A Joint Member   AB

DF

B



BA

0

BC

0.4

0.6

1

0

0

FEM   - 25

25

 

- 10

 

- 15

15

 

- 15 kN # m

Dist. CO

 

CB

-5

a M    - 30

Using these results, the shear at both ends o members AB and BC  are  are computed and shown in Fig. a. From this fgure,  A x

  =

M  A

  =

 

0  A y

  =

33 kN

30 kN # ma

 

C  y

    =

B y

  =

27   + 6

6 kN T  

  =

33 kN

Ans. 0  A x   =

Ans.

 A y B y

Ans.

  =

  =

M  A C  y 5 20

  =

  =

33 kN c 33 kN

30 kN # m B

6 kN T

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

500 lb

Determine the reactions at the supports and then draw the moment diagram. Assume Assume A is ixed. EI  is  is constant. *11–4.

800 lb>ft

B

 A

20 ft

 

D



20 ft

15 ft

500 lb 800 lb>ft

10.4 k · ft B

 A

20 ft

Solution FEMBC 

K  AB

  =

  =

wL2 12

=

 

  - 26.67, FEMCB

 

4EI   , K BC  BC  20

  =

4EI    DF AB 20

  =

  =

wL2 12

 

=

 

0 DFCB

Joint

 

A

Member

 

AB

BA

BC

0

0.5

0.5

DF Dist. CO

6.667

Dist. CO Dist. CO

0.8333

Dist. CO Dist. CO

 

- 9.583

0.1042

1.667

1.667

 

- 1.1979

  =

  =

1

0

 

- 0.41 7

 

4EI    20 4EI  4EI     + 20 20

=

0.5

6.667 7

2.396

 

- 2.39 0.8333 0.2994

M  A

  =

10.4 k # t

Ans.

 A x

  =

0

Ans.

0.1042

 A y

  =

1.56 k

Ans.

0.07485   - 0.1042

B y

  =

10.2 k

Ans.

C  y

  =

7.84 k

Ans.

- 0.1497

 

  - 7.5 k # t

- 19.1 7

0.2083   - 0.2994

 

7.84 k

- 7.5

0.5990   - 0.8333

 

20.7

DFBC 

CD

26.67

- 3.333

0.07485 10.4

  =

CB

4.7917   - .

0.2083

Dist.

a M 

13.33

 

  - 0.5(15)

10.215 k

15 ft



13.33

0.5990 0.2994

 

1 DFBA

- 26.67

4.7917 2.396

  =

  =

B

 

FEM

 

26.67 M CD CD

D



20 ft

1.555 k

 

 

- 20.7

7.5   - 7.5 k # t

Ans. M  A 10.4 k t A

#

=

 A x  A y

521

  =

  =

0 1.56 k T

B y

 

=

10.2 k

C  y

 

=

7.84 k

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

Determine the moments at  A, B, and C . Assume the support at B is a roller and A and C  are  are ixed. EI  is  is constant. 11–5.

3 k>ft 2 k>ft

 A

 

B

 

3 6 ft



24 ft

Solution (DF) AB

  =

(DF)BC 

  =

> 36   > 36   + > 24 0.6 (DF) 0 0 (DF)BA

 I 

  =

CB

(FEM) AB

  =

(FEM)BA

  =

(FEM)BC 

  =

(FEM)CB

  =

- 2(36)2 12  

=

 I 

  I 

  =

0.4

  =

  - 216 k # t

216 k # t

- 3(24)2 12  

=

  - 144 k # t

144 k # t

Joint

 

A

Mem.

 

AB

BA

BC

CB

0

0.4

0.6

0

- 21

216

- 144

144

DF

 

FEM

 

Dist. CO

a M 

 

B

- 28.8

- 14.4  

- 230

   



- 43.2  

187

 

- 21.6 - 187

 

- 122 k # t

Ans.

Ans. M  AB M BA BA M BC  BC  M CB CB 5 22

  =

  =

  =

  =

  - 230 k # t 187 k # t   - 187 k # t   - 122 k # t

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

Determine the moments at B  and C , then draw the moment diagram or the beam. The supports at A, B, C , and D  are pins. Assume the horizontal reactions are zero. EI   is constant. 11–6.

12 kN>m 4m C   A

  4m

D

B 4m 12 kN>m

Solution Member Stiffness Factor and Distribution Factor. Factor. K  AB

  =

(DF) AB

3EI  L AB   =

=

3EI    K BC  BC  4

 

1 (DF)BA

6EI  LBC 

  =

>

=

3EI  4

  =

>

6EI  4  

>

3EI  4   + 3EI  2

=

  =

3EI    2 1   (DF)BC  3

>

3EI  2

  =

>

>

3EI  4   + 3EI  2

  =

2   3

 Fixed End Moments. Reerring to the table on the inside back cover,

(FEM)BA

  =

wL2 8  

12(42) =

8

 

=

 

24 kN # m (FEM)BC 

  =

0

Moment Distribution. T  Tabulating abulating the above data,

Joint

 

A

Member

 

AB

BA

BC

DF

1

1/3

2/3

FEM

0

24

0

Dist.

 

-8

 

- 16

a M 

0

16

 

- 16

B  

Ans.

Using these results, the shear at both ends o members m embers AB, BC , and CD are computed and shown in i n Fig. a. Subsequently the shear and moment diagrams can be plotted, Figs. b and c, respectively.

Ans. M B   - 16.0 kN m M C  16.0 kN m   =

  =

523

#

#

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

Determine the moments at A, B, and C , then draw the moment diagram. Assume the support at B  is a roller and  A  and C  are   are ixed. EI  is  is constant. 11–7.

900 90 0 lb lb 90 900 0 lb lb

 B

 A

6 ft

400 lb

6 ft

6 ft



10 ft

10 ft

Solution (DF) AB

  =

(DF )CB

  =

(FEM) AB (FEM)BA

  0 (

0 (DF)BA

(FEM)BC 

  =

(FEM)CB

  =

  =

- 2(0.9)(18) 9

  =

  =

DF )BC 

  =

 

>

>

 I  18

>

 I  18   +   I  20

  =

0.5263

0.4737 =

  - 3.60 k # t

#

3.60 k t - 0.4(20) 8

 

=

  - 1.00 k # t

1.00 k # t

Joint

 

A

Mem.

 

AB

BA

BC

CB

0

0.5263

0.4737

0

DF FEM

 

Dist. CO

 

a M   

B

- 3. 0

3.60

 

- 1.368

- 0.684 - 4.28

 



- 1.00  

- 1.232

  2.23

1.00

- 0.616  

- 2.23

0.384 k # t

Ans.

Ans.

M  AB M BA M BA M CB

5 24

#   =

  =

  =

  =

  - 4.28 k t 2.23 k # t   - 2.23 k # t 0.384 k # t

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

Determine the moments at B  and C , then draw the moment diagram or the beam. Assume the supports at B and C  are  are rollers and A and D are pins. EI  is  is constant. *11–8.

12 kN>m

 A

12 kN>m

B

4m

C

D

6m

4m

Solution Member Stiffness Factor and Distribution Factor. Factor. K  AB

  =

(DF)BA

3EI  L AB

3EI    4

=

K BC  BC 

>

3EI  4

>

  =

>

3EI  4   + 3EI  3

  =

  =

2EI  LBC 

=

2EI  6  

9   (DF)BC  13

=

EI    3

(DF) AB

>

EI  3

  =

>

>

  =

3EI  4   +   EI  3

  =

1 4   13

 Fixed End Moments. Reerring to the table on the inside back cover, 12(42) wL2 (FEM) AB (FEM)BC  0 (FEM)BA 24 kN # m 8 8   =

  =

 

  =

 

=

 

=

Moment Distribution. T  Tabulating abulating the above data,

Joint

 

A

B

Member   AB DF

1

FEM

0

Dist.

a M 

 

BA

 

9   13

4   13

24 24

0

- 6.62 0

7.38

 

Due to symmetry, M CB 7.38 kN # m MCD CB   =

BC  

  - 7.38   - 7.38 kN # m

  =

Ans.

  - 7.38 kN # m

Ans.

Using these results, the shear at both ends o members AB  AB,, BC , and CD are computed and an d shown in Fig. a. Subsequently, the shear and moment diagram can be plotted, Figs. b and c, respectively.

Ans. M CB M CD 525

  =

  =

7.38 kN # m   - 7.38 kN # m

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

The bar is pin supported at points A, B, C , and D. I the normal orce in the bar can be neglected, determine the vertical reaction at each pin. EI  is  is constant. 11–9.

16 kN

 A

B 4m

4m

C 8m

D 4m

4m

16 kN

Solution Use antisymmetric load and symmetric beam. K BA BA

3EI    8

  =

(DF)BA

(DF)BC 

K BC  BC 

  =

6EI    8

  =

3EI    8 3EI  6EI    + 8 8  

=

0.3333

  =

6EI    8 3EI  6EI    +   8 8

=

0.6667

(3)(16)(8)

FEMBA

  =

Joint

16  

 

24 kN # m

A

B

Member   AB DF

=

BA

1

BC  

0.3333 0.6667

FEM

24 0

 M 

-8

 

- 16

16

 

- 16

#

kN m

Segment AB: a +  M B

+  F  y

  =

  =

 0; 

 A y(8)   + 16(4)   - 16

0;

V BL BL   + 6   - 16

  =

 

0

Segment BC : a +  M C  C 

+  F  y

  =

  =

 0;  0;

V BR BR(8)   + 16   + 16 V CL CL   + 4

  =

 

  =

+  F  y B y

  =

C  y

  =

  =

0;

 -

0

D y(8)   + 16(4)   - 16

CR   - 6   + 16 0 - V CR   V BL   +   V BR 10   + 4 14 kN   =

0;

 

  V CL   +   V CR

  =

  =

  =

  =

4   + 10

  =

  =

 

 

0

Segment CD: a +  M C  C 

 

0  A y

  =

  =

6 kN

V BL BL

  =

10 kN

V BR BR

  =

4 kN

V CL CL

  =

4 kN

 

0 D y

Ans.

Ans.   =

CR V CR

6 kN

  =

Ans.

10 kN

14 kN 5 26

 A y

  =

 kN

D y

  =

 kN

Ans.

B y

  =

14 kN

Ans.

C  y

  =

14 kN

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

300 lb

Determine the moments at B  and C , then draw the moment diagram or the beam. Assume the supports at B and C  are  are rollers and A is a pin. EI  is  is constant. 11–10.

200 lb>ft

Solution

 A

B

 

D



Member Stiffness Factor and Distribution Factor. Factor. K  AB

  =

3EI  L AB

(DF)BA

  =

(DF)CB

  =

3EI  10

=

 

=

 

0.3EI 

0.3EI  0.3EI   + 0.4EI 

  =

 

1 (DF)CD

  =

K BC  BC 

  =

4EI  LBC 

3   (DF)BC  7

  =

4EI  10

=

 

10 ft =

0.4EI 

0.4EI  0.3EI   + 0.4EI 

4   7

  =

0

 Fixed End Mome Moments. nts.   Reerring to the table on the inside back cover, (FEM)CD   - 300(8)   - 2400 lb # t (FEM)BC  (FEM)CB   =

(FEM)BA

  =

 

  =

2 wL AB

8

 

200(102) =

 

8

  =

  =

0

2500 lb # t

=

Moment Distribution. T  Tabulating abulating the above data,

Joint

 

A

B

Member   AB



BA

DF

1

3 7

FEM

0

250 0

Dist.

 

BC

 

 

- 514.29

 

 1

0

0

0

357.15

 

- 153.0

 

 

- 73.47

 

51.03

Dist.

 

- 21.87

 

- 29.1

CO Dist.

 

- 10.50

 

24.49 - 13.99

CO

7.29

 

- 3.12

 

CO

 

Dist.

 

- 1.50

CO

 

- 0.45

 

CO

 

 

- 0.21

CO

 

- 0.0

342.86

 

- 102.05

 

102.05

 

- 48.98 48.98

- 14.58 14.58

   

7.00

 

a M 

  0

- 2.08 2.08

 

- 1.00 1.00

 

- 0.30 0.30

 

- 0.15

- 0.09

0.15

  CO Dist.

- 7.00

- 0.29 0.15

Dist.

- 342.86

- 0.59 0.50 0

Dist.

 

- 2.00 1.04

Dist.

714.29

- 4.17 3.50

- 0.03

 

0.07 - 0.04

650

 

- 650

- 2400

- 714.29

- 97.9

CO

Dist.

 

- 204.09 171.43

 

2400

- 85.71

CO Dist.

4 7

120 0

CO Dist.

CD

- 1071.43   - 1428.57

CO Dist.

CB

0.04 0.04 2400   - 2400 lb # t

527

Ans.

10 ft

8 ft

 

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11–10.

(Continued)

Using these results, the shear at both ends o members  AB, BC , and CD are computed and shown in Fig. a. Subsequently, the shear and moment diagrams can be plotted, Figs. b and c, respectively.

Ans. M BA M BC  M CB M CD 5 28

  =

  =

  =

  =

650 lb # t   - 650 lb # t 2400 lb # t   - 2400 lb # t

 

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Determine the moments at  A  and B, then draw the moment diagram. Assume the support at B is a roller, C   is a pin, and A is ixed. 11–11.

12 kN>m C B

 A

5m

2.5 m

Solution (DF) AB

  =

(DF)BC 

  =

(FEM) AB (FEM)BA (FEM)BC 

  (DF) 0.6 (DF) 0

  =

  =

  =

BA

CB

- 12(5)2 12  

25 kN m # (FEM)CB

Joint   A Mem.   AB DF

0

FEM   - 25

=

  =

  =

>

0.4

>

4 I  5   + 3 I  2.5

  =

0.4

1

  - 25 kN # m

  =

0

B BA

>

4 I  5



BC

0.6

CB

1

  25

- 10   - 15 -5  M 

  - 30

M  AB

  =

M BA BA

  =

M BC  BC 

  =

15   - 15

  - 30 kN # m 15 kN # m

  - 15 kN # m

0 Ans. Ans. Ans.

Ans. M  AB

529

  =

M BA

  =

M BC  BC 

  =

  - 30 kN # m 15 kN # m

  - 15 kN # m

 

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12 kN

Determine the moments at B and C , then draw the moment diagram or the beam. Assume C  is  is a ixed support. EI   is constant. *11–12.

8 kN>m

 A

B



6m

Member Stiffness Factor and Distribution Factor. Factor.   =

(DF) AB

(DF)BC 

3EI  LBA   =

  =

=

3EI  6  

EI    2

=

 

1 (DF)BA

K BC  BC 

>

  =

>

EI  2

  =

>

EI  2   +   EI  2

> > >

EI  2 EI  2   +   EI  2

  =

 

4EI  LBC    =

0.5 (DF)CB

 Fixed End Moments.

=

Joint

4EI  8  

=

  =

(FEM)BC 

  =

(FEM)CB

  =

8(62)

wL2 8  

 -

=

PL 8

 

PL 8

 

 

8

=

 -

=

0.5

8

12(8) =

8

 

=

 

=

A

DF

1

FEM

0

Dist.

 

B BA

  =

0

a M 

C  BC

0.5

 

- 12

- 12

 

- 12

  0

24

CB

0.5

36

CO

0 12

-6  

- 24

6 kN # m

Ans.

Using these results, the shear and both ends o members  AB  and BC  are   are computed and shown in Fig. a. Subsequently, the shear and moment m oment diagrams can be plotted, Fig. b.

36 kN # m

12(8)

 

Member   AB

EI    2

Reerring to the table on the inside back cover, (FEM)BA

4m

Moment Distribution. T  Tabulating abulating the above data,

Solution

K BA BA

4m

  - 12 kN # m

12 kN # m

Ans. M  AB M BA M BA M CB 5 30

  =

  =

  =

  =

0 kN # m 24 kN # m   - 24 kN # m   - 6 kN # m

 

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Determine the moments at the ends o each member o the rame. Assume the joint at B is ixed, C  is  is pinned, and A  is ixed. The moment o inertia o each member is listed in the igure. E 29(103) ksi. 11–13.

2 k>ft B  I BC  

  =

4

 800 in

5



12 ft

8 ft

4k

 I   AB 

 550 in4

5

8 ft

 A

Solution (DF) AB

  =

(DF)BA

  =

(DF)BC 

  =

0

>

4(0.6875 I BC  BC ) 16

>

 

0.5926 (DF)CB

- 4(16) 8

  =

1

  =

(FEM)BC 

  =

Joint

 

A

Mem.

 

AB

BA

0

0.4074

FEM

 

 

- 2(122) 12  

- 8.0

Dist. CO

a M 

0.4074

 

=

  =

 

  - 24 k # t (FEM)CB

8 k # t 24 k # t

  =

B

1

- 24.0 9.482

 

3.259

CB

0.5926

 

8.0

C  BC

6.518

Dist. CO

=

  =

  - 8 k # t (FEM)BA

(FEM) AB

DF

>

4(0.6875 I BC ) 16   + 3 I BC  12

24.0

 

- 24.0

- 12.0

4.889

7.111

2.444

- 2.30

19.4

 

- 19.4

0 k # t

Ans.

Ans. M  AB M BA M BC  M CB 531

  =

  =

  =

  =

  - 2.30 k # t 19.4 k # t   - 19.4 k # t 0 k # t

 

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4 k>ft

Determine the internal moments acting at each joint. Assume A, D, and E are pinned and B and C  are   are ixed joints. The moment o inertia o each member is listed in the igure. Take E 29(103) ksi. 11–14.

 A

  =

B

 I   ABC  

 800 in

5

6 ft



4

6 ft

18 ft

20 k  I BD 

 600 in

5

4

 I CE 

 1000 in

5

D

Solution (DF) AB

  =

(DF)BA

  =

(DF)BC 

  =

(DF)BD

1

>

3( I  ABC ) 6

>

>

>

3( I  ABC ) 6   + 4( I  ABC ) 18   + 3(0.75 I  ABC ) 12

  =

0.5496

0.2443

  =

0.2061 4( I  ABC ) 18

(DF)CB (DF)CE (DF)DB

  =

0.5844

  =

  =

(DF)EC 

(FEM) AB

  =

(FEM)BA

  =

(FEM)BC 

  =

(FEM)CB

  =

(FEM)CE

  =

 -

>

  =

 

12

  =

0.4156

1

4(6)2 =

  - 12.0 k # t

 -

4(18)2  

12

=

  - 108 k # t

108 k # t

 -

  =

20(12) 8

 

=

Mem.   AB 1

FEM   - 12.0

  - 30.0 k # t

#

30.0 k t (FEM)DB

Joint   A DF

>

12.0 k # t

  =

(FEM)EC  (FEM)BD

>

4( I  ABC ) 18   + 3(1.25 I  ABC ) 12

  =

0 B

C

E

D

BA

BD

BC

CB

CE

EC

DB

0.5496

0.2061

0.2443

0.4156

0.5844

1

1

12.0

 

- 108

108

- 30

30

  12.0 52.76 6.0 5.61

19.79

  2.10

 

23.45   - 32.42   - 45.58   - 30

- 16.21

11.73   - 15.0

2.49

1.36

0.68

1.25

1.91

- 0.37   - 0.14   - 0.17   - 0.52   - 0.73 - 0.26   - 0.08  M 

 0

0.14

0.05

0.06

76.2

21.8   - 98.0

0.03

0.05

89.4   - 89.4

0

5 32

0

6 ft

4

E

 

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11–14.

(Continued)

M  AB

  =

0

M BA BA

  =

M BD BD

  =

M BC 

  =

M CB

  =

M CE CE

  =

M EC  M DB

  =

  =

Ans.

7 .2 k # t

Ans.

21.8 k # t

Ans.

  - 98.0 k # t 89.4 k # t

  - 89.4 k # t 0 0

Ans. Ans. Ans. Ans. Ans.

Ans. M  AB

M BA BA

  =

M BD BD

  =

M BC  M CB CB M CE CE M EC  EC  M DB DB 533

  =

  =

  =

  =

  =

  =

0 7 .2 k # t 21.8 k # t   - 98.0 k # t 89.4 k t #   - 89.4 k # t 0 0

 

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Determine the reactions at  A  and D. Assume the supports at A and D are ixed and B and C  are  are ixed connected. EI  is  is constant. 11–15.

8 k>ft B



15 ft

 A

D

24 ft

Solution (DF) AB

  =

(DF)DC 

  =

(DF)BA

  =

(DF)CD

  =

(DF)BC 

  =

(DF)CB

  =

(FEM)BA

  =

- 8(24)2 12 384 k # t

(FEM) AB (FEM)BC  (FEM)CB (FEM)CD

  =

  =

  =

 

0

>

 I  15

>

# =

(FEM)DC 

  - 384 k t

  =

0

 

A

Mem.

 

AB

BA

0

0.6154

B

118.16

C BC

22.72

147.69

 

- 73.84 28.40

4.37

5.46

 

1.05

 

0.16

0.20

 

0.03

0.04

 

146.28

- 28.40

292.57  

0.0 1

 

 

- 5.46

   

- 1.05

   

- 0.20

   

- 0.04

   

- 292.57

- 0.01

   

- 0.17

- 0.0

0.02

 

- 0.84

- 0.33

0.10

 

- 4.37

- 1.68

0.53

 

- 22.72

- 8.74

2.73

 

- 118.1

- 45.44

14.20

- 0.02

0.0 1

a M 

 

- 0.10

0.06

 

73.84

- 0.53

0.32

0

- 147.69   - 236.31

- 2.73

1.68 0.84

 

- 14.20

8.74

0.6154

DC  

384

236.31

 

CD

0.3846

- 384

45.44

D

CB

0.3846

 

FEM

0.6154

  =

0

  =

Joint DF

>

 I  15   +   I  24 0.3846

- 0.03

- 0.01

292.57   - 292.57   - 146.28

Ans.  A x 29.3 k   =

 A y

Thus, rom the ree-body diagrams,

  =

M  A

  =

96.0 k

146 k # t

 A x

  =

29.3 k

D x

  =

29.3 k

Ans.

D x

  =

29.3 k

 A y

  =

96.0 k

D y

  =

96.0 k

Ans.

D y

  =

96.0 k

Ans.

M D

M  A

  =

146 k # t

M D

  =

146 k # t

5 34

  =

146 k # t

 

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18 kN

The rame is made rom pipe that tha t is ixed connected. I it supports the loading shown, determine the moments developed at each o the joints. EI  is  is constant. *11–16.

18 kN



B

4m

D

 A

4m

4m

4m

Solution FEMBC 

K  AB

  =

DF AB

  =

 -

  K CD CD

  =

2PL 9  

 

DFDC 

  =

DFCD

DFBC 

  =

DFCB

 

  - 48, FEMCB

4EI   , K BC  BC  4

  =

DFBA

=

  =

  =

0

  =

4EI  4   4EI  4EI  4   + 12  

  =

1   - 0.75

2PL 9  

=

48

4EI    12

0.75

=

  =

  =

0.25

Joint

 

A

Member

 

AB

BA

BC

CB

CD

0

0.75

0.25

0.25

0.75

DF

 

FEM Dist. CO

18

Dist. CO

0.281

Dist.  M 

12

 

20.6

1.5

 

- 0.75

 

- 12

 

 

- 1.5

 

 

0.0938 - 0.0938 0.0234   - 0.0234 41.1

- 18

- 4.5

0.75

  0.0704

- 41.1

0

 

6

0.1875   - 0.1875

 

DC  

- 36

0.5625

41.1

D

48

-6 4.5

2.25

C

- 48 36

Dist. CO

B

 

- 0.5625

 

  - 0.0704

 

- 41.1

- 2.25 - 0.281  

- 20.6 kN # m

Ans.

Ans. M  AB

M BA BA M BC  M CB CB

535

  =

  =

  =

  =

M CD

  =

M DC  DC 

  =

20.6 kN # m 41.1 kN # m

#

m   - 41.1 kN 41.1 kN # m

  - 41.1 kN # m   - 20. kN # m

 

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11–17. Determine the moments at the ixed support  A  and  joint D  and then draw the moment diagram or the rame. Assume B is pinned.

4 k>ft



 A

D 12 ft

12 ft 12 ft

B

Solution Member Stiffness Factor and Distribution Factor. Factor. K  AD

  =

4EI  L  

=

 

4EI  12  

(DF) AD

  =

0

(DF)DC 

  =

(DF)DB

EI    3

=

(DF)DA

  =

K DC  DC 

  =

3EI  L

  =

 

> >4   + >4

=

EI  3

>

  =

  K DB DB

EI  3   +   EI 

  EI 

>

EI  4 EI  3   +   EI  4   +   EI  4

>

>

  =

  =

3EI  12  

=

EI    4

0.4

 

0.3 (DF)CD

  =

(DF)BD

  =

1

 Fixed End Momen Moments. ts.   Reerring to the table on the inside back cover,

(FEM) AD

(FEM)DA

wL2  12

  =

wL2 12

  =

(FEM)DC 

  =

(FEM)CD

  =

 

 

=

wL2  8  

=

 -

 -

=

 

12

4(122) 12

 -

(FEM)BD

4(122)

 

=

=

48 k # t

4(122) 8

  =

 

  - 48 k # t

=

  - 72 k # t

(FEM)DB

  =

0

Moments Distribution. T  Tabulating abulating the above data,

Joint

 

A

Member   DF FEM

a M 

C

B

AD

DA

DB

DC

CD

BD

0

0.4

0.3

0.3

1

1

0

0

0

0

- 48

Dist. CO

D

48

0

9.60

7.20

57.6

7.20

- 72 7.20

4.80

- 43.2

  - 4.8 k # t

5 36

Ans.

 

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11–17.

(Continued)

Using these results, the shears at both ends o members  AD, CD, and BD are computed and shown in Fig. a. Subsequently, the shear and moment diagrams can be plotted, Figs. b and c, respectively.

Ans. M  AD

  =

M DA DA

  =



  =

M DC  DC 

  =

M CD

  =

M BD BD

  =

DB

537

  - 43.2 k # t 57.6 k # t

#

7.20 k t   - 4.8 k # t 0 k # t 0 k # t

 

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6 kN>m

Determine the moments at  A, C , and D, then draw the moment diagram or each member o the rame. Support  A  and joints C   and D  are ixed connected. EI   is constant. 11–18.



D

E

6m

 A

B

8m

7m

Solution

 

FEM AC 

  =

0 FEMBD

FEMCD

  =

 -

wL2 12

FEMDE

  =

 -

wL2 8

  Joint Member  

DF

 

 

=

 -

=

 -

0

6(82)  

12

=

6(72) 8

 

=

  - 32 kN # m

  =

  - FEMDC 

  - 36.75 kN # m

A

B

AC

BD BD

CA CA

CD

DC

DB

DE

ED

0

1

0.5714

0.4286

0.35

0.35

0.3

1

C

- 32

32

 

- 36.75

13.714

1.6625

1.6625

1.4250

0.83125

6.8571

 

FEM Dist. CO

  =

18.286 9.1429

D

Dist.

0.4750 0   - 0.35625   - 2.4000   - 2.4000

CO   - 0.23750

 

- 1.2000   - 0.17813

Dist.

0.68571

0.51429

a M  M  AC 

  =

  =

BD M BD

M CA CA

  =

M CD

  =

M DC 

  =

M DB

  =

M DE

  =

M ED

  =

8.905

18.50   - 18.50

0.062344 0.062344

Ans.

0 18.5 kN # m

Ans.

38 kN # m

  - 0.675 kN # m   - 37.3 kN # m

 

- 2.0571 0.053438

38.0 0   - 0.6752   - 37.33 kN # m

8.91 kN # m

  - 18.5 kN # m

E

Ans. Ans. Ans. Ans.

0

Ans. M  AC 

M CA

  =

  =

M CD M DC 

5 38

  =

  =

M DB

  =

M DE DE

  =

8.91 kN # m 18.5 kN # m

 -

#

18.5 kN m 38 kN # m

  - 0. 75 k kN N#m   - 37.3 kN # m

 

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Determine the moment at B, then draw the moment diagram or each member o the rame. Support Support A is pinned. EI   is constant. 11–19.

1.5 k>ft

 A

 

B

12 ft



12 ft

5 ft

Solution FEMBC 

  =

FEMBA

  =

Joint

wL2 8  

 

Member DF

0 1.5(122) =

8

 

=

A  

27 k # t B



AB

BA

BC

CB

1

0.44828

0.55172

0

FEM

27

- 12.103   - 14.897 - 7.4485  M 

M B

  =

0

  - 14.9 k # t

14.897   - 14.897   - 7.4485 Ans.

Ans. M B   - 14.9 k t   =

539

#

 

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10 k

Determine the moments at B and C , then draw the moment diagram or each member o the rame. Assume the supports at A, E, and D are ixed. EI  is  is constant. *11–20.

2 k>ft 8 ft

 A

8 ft



B 12 ft 16 ft

E

Solution

D

Member Stiffness Factor and Distribution Factor. Factor. K  AB

  =

4EI  L AB

4EI  12

=

 

EI    3

=

(DF) AB

  =

(DF)EB

  =

(DF)BC 

  =

(DF)BE

  =

(DF)CB

  =

(DF)CD

K BC  BC 

(DF)DC 

  =

  =

  K BE BE

  K CD CD

 

0 (DF)BA

> >4   + >4

  =

EI  4

>

EI  3   +   EI 

>

EI  4

>

  =

  =

  EI 

>

EI  4   +   EI  4

  =

4EI  L

  =

 

4EI  16

=

 

EI    4

=

> >4   + >4

EI  3

>

EI  3   +   EI 

  EI 

  =

0.4

0.3

0.5

  =

 Fixed End Moments. Reerring to the table on the inside back cover,

(FEM) AB

  =

(FEM)BA

  =

(FEM)BC 

  =

(FEM)CB

  =

(FEM)BE

  =

 -

2 wL AB  

12

 -

 

=

PLBC 

8

PLBC 

8

 

 -

2(122)  

12

2(122)

2 wL AB

12

=

 

 

12

=

 -

(FEM)EB

10(16)  

8

8   =

  - 24 k # t

24 k # t

=

 

=

  - 20 k # t

20 k # t

10(16) =

=

=

(FEM)CD

  =

(FEM)DC 

  =

0

Moment Distribution. T  Tabulating abulating the above data,

Joint   A

B

Member   AB DF

0

CO

   

24

- 1.60

BC

0.3 0

 

0.3

 

- 1.20

- 1.20

1.50

   

- 0.06

 

- 0.045

- 0.03

Dist.

0.075 0.0375  

a M    - 23.79

0.05625

20

 

24.41

0.3096

- 10

 

 

1.50

0.30

0.15

0.75

- 0.045

- 0.375

  - 0.1875

- 0.0225

0.0 05625 - 0.0016875

5 40

DC

EB

0

0

0

0

0

-5

 

- 0.6

0.30 0.15

0.75

- 0.375  

0.028125   - 0.01406 10.08

E

0.5

 

0.0 1125

- 24.72

D

- 10

  - 0.60

0.05625

- 0.00225   - 0.0016875

CD

0.5

- 20

1.0 0

Dist.

CB

  -5 2.0 0

CO

CO Dist.

BE

- 0.80

Dist.

CO

BA

0.4

FEM   - 24 Dist.

C

 

- 0.1875   - 0.0225

0.0 1125

- 0.01406

0.0 05625

- 10.08 k # t   - 5.032

0.028125   0.1556

 

Ans.

 

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*11–20.

(Continued)

Using these results, the shear at both ends o members AB, BC , BE, and CD are computed and shown in Fig. a. Subsequently, the shear and moment diagrams can be plotted.

541

 

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*11–20.

(Continued)

Ans.  M 

  - 23.79

24.41 0.3096   - 24.72 10.08   - 10.08 k # t   - 5.032 0.1556 5 42

 

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Determine the moments at D  and C , then draw the moment diagram or each member o the rame. Assume the supports at A and B are pins. EI  is  is constant. 11–21.

16 kN

1m

3m

D



 A

B

4m

Solution K DA DA

  =

  K CB CB

  =

3EI  L  

=

(DF) AD

  =

(DF)BC 

  =

(DF)

  =

(DF)

  =

DC 

CD

3EI    4

 

1 (DF)DA

K CD CD

  =

  =

>

4EI  L

(DF)CB

EI 

3EI  4   +   EI 

  =

4

 

=

4EI  4  

=

>

  EI 

3EI  4   =

>

  =

3EI  4   +   EI 

3   7

 

7

543

 

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11–21.

(Continued)

Moment Distribution. No sidesway, Fig. b.

Joint

 

A

D

Member   AD

DC

CD

CB

4   7

4   7

3   7

1

3

0

0

1

3   7

FEM

0

0

 

-9 5.143  

3.857

 

CO

 

- 0.735

Dist.

 

- 0.070

Dist.

 

- 0.060

Dist.

 

- 0.006

Dist.

0.017

0.0 03   - 0.010   - 0.007

0.0 03

a M 

0.020

0.034   - 0.011   - 0.009

0.026

CO

0.210

0.040   - 0.120   - 0.090

0.030

CO

0.245

0.420   - 0.140   - 0.105

0.315

CO

2.572

0.490   - 1.470   - 1.102

0.367

CO

4.598   - 4.598

0

BC  

- 1.714   - 1.286

- 0.857

Dist.

B

DA

DF

Dist.

C

2.599

  - 2.599 kN # m

0

Using these results, the shears at A and B are computed and shown in Fig. d. Thus, or the entire rame,

+

 F   x

  =

(FEM)DC 

(FEM)CD

0;

 

  =

1.1495   - 0.6498   -   R

 -

Pb2a L2

 

L2

 

 -

16(32)(1) 42

 

16(12)(3)

Pa2b   =

=

=

42

 

=

=

  =

 

0 R

  =

0.4997 kN

  - 9 kN # m

3 kN # m

5 44

 

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11–21.

(Continued)

For the rame in Fig. e, Joint

 

A

D

Member   AD DF

1

FEM

0

C

DA

DC

CD

CB

3

4

4

3

 

7 - 10

 

Dist.

4.286

CO

 

Dist.

 

 

7 0

7 0

5.714

5.714

2.857

2.857

 

 

1

7 - 10

0

4.286

- 0.817   - 0.817

Dist.

0.350

CO

 

0.467

0.467

0.234

0.234

0.350

- 0.100   - 0.134   - 0.134   - 0.100  

CO

- 0.0 7   - 0.0 7

Dist.

0.029

CO

 

-

0

0.008 - . 7

Dist.

a M 

 

BC  

- 1.224   - 1.633   - 1.633   - 1.224

CO

Dist.

B

 

0.038

0.038

0.0 19

0.0 19

  -

  0.011 6.667

0.029

  0.011 0.008   - 6.667 6.667 kN # m

0

Using these results, the shears at  A  and B  caused by the application o R   are computed and shown in Fig.  f . For the entire rame,

+

 F   x

  =

 

0;

R    - 1.667   - 1.667

 

0

  =

R

  =

3.334 kN

Thus, M DA DA

  =

M DC  DC 

  =

M CD

M CB

  =

  =

4.598   + ( - 6.667)

a 0.4997  b 3.334

  - 4.598   + (6.667)

 

=

 

=

0.4997

3.334 a0.4997  b 2.599   + (6.667) a  b 3.334

  =

  - 2.599   + ( - 6.667)

a 0.4997  b 3.334

3.60 kN # m

Ans.

  - 3.60 kN # m

Ans.

3.60 kN # m

 

=

  - 3.60 kN # m

Ans.

Ans.

Ans. M DA M DC  M CD M CB

  =

  =

  =

  =

545

3. 0 kN # m   - 3.60 kN # m 3.60 kN # m   - 3.60 kN # m

 

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1.5 k>ft

Determine the moments acting at the ends o each member o the rame. EI  is  is the constant. 11–22.

 15 k B

 



20 ft

D

 A

24 ft

(DF) AB

  =

(DF)DC 

  =

(DF)BA

  =

(DF)CD

  =

(DF)BC 

  =

(DF)CB

1

>

>

3 I  20

>

3 I  20   + 4 I  24

  =

0.4737

0.5263

  =

Consider no sidesway Joint

 

A

B

Member   AB DF 1

BA 0.4737

BC 0.5263

Dist.

34.11

37.89

 

CO Dist. Dist.

- 9.97

- 4.98

4.98

2.62

  - 2.62

  - 1.31

  1.31

0.69

  - 0.69

  - 0.35

  0.35

0.16

0.18

0.04

CO 0.62

CO Dist. CO Dist. CO Dist.

0.0 1

a M 

46.28

  =

(FEM)BC 

  =

(FEM)CB

  =

(FEM)BA

- 1.5(24) 12 72 k # t  

  =

2 =

 

 

- 8.98

 

- 2.36

 

- 0.62

  - 0.18

 

- 0.16

- 0.09 0.05

0.09   - 0.05

 

- 0.04

- 0.02

0.02

0.0 1

  - 0.01

 

- 0.01

- 4 .28

46.28

0

  - 72 k # t

(FEM)CD (FEM)DC  0 +  F  d 0 (or the rame without sidesway):  x   =

  =

  =

R   + 2.314   - 2.314   - 15 R 15.0 k

  =

0

CD 0.4737

- 37.89   - 34.11

9.97

2.36

Dist.

 

18.95

8.98

D

72.0

- 18.95

CO

  =

CB 0.5263

- 72.0

FEM

(FEM) AB

C

  - 4 .28 k # t

DC   1

5 46

 

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11–22.

(Continued)

Joint

 

A

Mem.

 

AB

DF

B

1

 

FEM

BA

BC

CB

0.4737

0.5263

0.5263

- 100

Dist. CO

 

- 12.47

 

Dist. CO

  - 0.8

 

0.23

 

CO Dist.

a M 

M BC 

  =

M CB

  =

M CD

  =

M  AB

  =

 

  - 0.06

Dist.

  =

26.32

 

3.125   + 3.125

  =

 

0

 

- 12.47 3.28

- 0.8

- 0.48 0.25

0.13

0.13

- 0.07

 

- 0.07

- 0.03

 

- 0.03

0.02

0.02

- 62.50

62.50

62.50

0.23   - 0.06 0.02

 

- 62.50 k # t

6.25 k   =

Ans.

  =

Ans.

  =

  =

 

- 0.9

0.02

  =

  M DC  DC 

47.37

- .93 3.64

0.25

15  a 6.25 b ( - 62.5)   - 104 k # t 15 b (62.5) 104 k # t   - 46.28   +  a 6.25 15 46.28   + a b (62.5) 196 k # t 6.25 15 b ( - 62.5)   - 196 k # t   - 46.28   + a 6.25 46.28   +

1

1.82

- 0.48

CO

M BA

26.32

- 0.9

 

Dist.

  =

52.63

1.82

CO

R

52.63

- .93 3.64

3.28

Dist.

0.4737

DC  

- 100

- 13.85   - 13.85

 

CO

D CD

 

47.37

Dist.

C

Ans.

Ans. Ans. Ans.

M BA M BC  M CB M CD CD M  AB

#   =   =

  =

  =

  =

k t   104 - 104 k # t

19 k # t   - 19 k # t 0   M DC  DC    =

547

 

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Determine the moments at the ends o each member o the rame. The The members are ixed connected at the supports and joints. EI  is  is the same or each member. 11–23.

4 k>ft  

B

 



20 k

6 ft

15 ft

Solution 15 k

PL wL2 FEMs or AB use  , and or BA use  . Each member 8 12 4EI  has a K  L  .

6 ft

  =

 A

Joint

 

A

Member

 

AB

BA

BC

CB

CD

0

0.5556

0.4444

0.4444

0.5556

- 22.5

22.5

- 75

75

DF

 

FEM

B

 

14.583 d 29.167

C

23.333

 

- 33.333

- 16.667 4.630 d

9.259

7.407

1.440

1.152

 

- 5.182

 

- 1.646

d 0.457

0.366 - 0.128

 

- 0.256 0.183

0.036 d

0.071

0.057

 

- 0.081

- 0.041 - 2.303 Member AB: b +  M B

  =

0;

 

62.917

b +  M C 

  =

0;

 

  =

 

+

 F   x

  =

0;

 

- 2.917

50.643

  =

0

2.449 k

- 50.643   - 25.314   +   D x(12) D x .330 k

R

  =

 

- 6.482

              d

 

- 2.058

              d

 

-

              d

0.320

- 0.013

  =

0

  =

Frame:

- 20.833

              d

 

- 3.241

 

- 1.029

 

- 0.102

 

- 0.016

 

- 0.160

 

- 0.051

              d

0.028

62.917   - 2.303   - 15(6)   + A x(12) A x

Member CD:

 

 

- 41.667

0.576

0.229

0.0 18

0

3.704

- 0.823

0.023

DC  

11.667

- 2.593 0.720 d

 

D

20   + 15   - 2.449   - 6.330

  =

26.221

 

- 50. 43

 

- 25.314

D

5 48

 

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11–23.

(Continued)

Joint

 

A

Member

 

AB

BA

BC

CB

CD

0

0.5556

0.4444

0.4444

0.5556

DF FEM

 

B

- 100

 

C

- 100

 

27.778 d   - 55.556

- 6.173 d   - 12.346 1.372 d

 

2.744

- 0.305 d   - 0.610 0.068

 

0.135

- 0.030 - 77.260   - 54.551

 

44.444

22.222

22.222

- 9.877

 

- 9.877

- 4.938

 

- 4.938

2.195

2.195

1.097

1.097

0.108

0.108

0.054

0.054

- 0.024

 

- 0.488 - 0.244

   

 

 

0

 

   

54.551

- 100

0.5556

              d

- 12.346

              d

2.744

              d

- 0.610

 

27.778

- 6.173 1.372

- 0.305

              d

 

0.135

- 0.024

54.551

DC  

- 100

44.444

- 0.488 - 0.244

D

0.068

- 0.030 - 54.551

 

- 77.260

Member AB and CD: b +  M B

+

 F   x

  =

  =

  0; 

0;

 A x(12)   - 54.55   - 77.260  A x

  =

 

=

  D x

  =

0

  =

10.984 k

Frame: R

10.984   + 10.984

  =

21. 89 k

Thus M  AB

  =

M BA

  =

M BC  BC 

  =

M CB CB

  =

M CD CD

M DC 

  =

  =

  - 2.303   + ( - 77.260) 62.917   + ( - 54.551)

a 26.221 b 21.968

a 26.221 b 21.968

  - 62.917   + ( + 54.551) 50.643   + (54.551)

 

=

=

a 26.221 b 21.968

a 26.221 b 21.968

  - 50.643   + ( - 54.551)

 

 

=

 

  - 94.5 k # t

  - 2.19 k # t

Ans.

2.19 k # t

Ans.

=

116 k # t

26.221

a 21.968 b 26.221   - 25.314   + ( - 77.260) a b 21.968

 

 

Ans.

=

=

  - 116 k # t   - 118 k # t

Ans.

Ans. M  AB

M BA BA

  =

  =

  - 94.5 k # t   - 2.19 k # t

Ans.

M BC  M CB Ans.

  =

  =

M CD CD

  =

M DC 

  =

2.19 k t 116 k # #t

  - 11 k # t   - 118 k # t

549

 

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6 k>ft

Determine the moments acting at the ends o each member. Assume the supports at  A  and D  are ixed. The moment o inertia o each member is indicated in the igure. 29(103) ksi. E *11–24.

B

  =

 I BC  

 1200 in

5

 I CD 

 15 ft  I   AB 

 800 in

5

(DF) AB

24 ft

(DF)DC 

  =

0

  =

a 23  b > 15 a 23  b > 15   + > 24  I BC   I  BC 

(DF)BA

  =

 I BC   I  BC 

(DF)BC 

  =

(DF)CB

  =

(DF)CD

0.5161

  I BC  BC 

0.4839

>

 I BC  BC  24

>

>

0.5 I BC  10   +   I BC  24

  =

=

  =

0.4545

0.5455

Consider no sidesway Joint Mem.

   

DF

A AB

B

0

CO

74.32

Dist.

0.5161

0.4839

0.4545

0.5455

148.64

139.36

 

- 5.45 31.67

 

16.89

Dist.

7.66

 

4.09

Dist.

 

- 130.90

1.74

 

 

 

- 31.67

 

- 38.01  

15.84

 

- 7.20

 

- 19.01

- 8.64  

3.83

 

- 78.55

- 1.74

 

0.93

 

- 0.87

Dist. CO

0.45  

0.42 - 0.20

 

- 0.40 0.21

 

0.22

- 0.47  

0.10

0.10

 

- 0.10

 

- 0.11

CO

 

0.05

Dist.

0.02

a M 

96.50

(FEM) AB

  =

(FEM)BC 

  =

(FEM)CB

  =

(FEM)

  =

(FEM)BA

- 6(24)2 12  

  =

=

(FEM)

- 193.02

0

  - 288 k # t

  =

0

DC 

0  (or the rame without sidesway):

R   + 19.301   - 30.968

11.

  =

 

288 k # t

CD

 F   x

193.02

0.02

k

  =

0

 

0.87

- 0.05

- 0.02 206.46

- 1.04 - 0.24

 

0.05

 

- 4.32

- 2.09

CO

Dist.

0

- 157.10

69.68

- 3. 0

1.86

D DC

288

- 15.84

8.18

CO

  =

CD

33.78

CO

R

CB

- 288

Dist.

+

BC

 

FEM

C

BA

   

- 0.0

- 0.03 - 206.46

 

- 103.22 k # t

 



 600 in

5

4

D

4

 A

Solution

4

10 ft

5 50

 

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*11–24.

(Continued)

Joint

 

A

Mem.

 

AB

BA

BC

CB

CD

DC  

0

0.5161

0.4839

0.4545

0.5455

0

DF FEM

59.26

 

Dist. CO

 

B

59.26

- 30.58

- 15.29

Dist.

 

- 1. 8

- 0.84

 

 

Dist. 0.32

Dist.

 

- 0.09

- 0.05

 

 

Dist.

a M 

 

0.65

CO

 

0.04 49.28

39.31

10 0

- 28.68   - 45.45   - 54.55

11.73

Dist.

CO

 

- 22.73   - 14.34

5.87

D

10 0

 

CO CO

C

11.0 0

6.52

3.26

5.50

- 1.58

 

- 2.50

- 1.25

 

- 0.79

0.60

0.36

0.18

0.30

- 0.09

 

- 0.14

- 0.07

 

- 0.04

0.03

 

 

- 27.28

7. 82 3.91

 

- 3.00  

- 1.50

0.43 0.22

 

- 0.16  

0.02

0.02

- 39.31   - 50.55

50.55

- 0.08 75.28

k # t

551

 

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*11–24.

(Continued)

(FEM)CD

(FEM) AB R

 

=

M  AB

  =

M BA

  =

M BC 

  =

M CB

  =

M CD CD

  =

M DC  DC 

  =

  =

  =

(FEM)DC 

(FEM)BA

  =

5.90   + 12.585 96.50   +

  =

  =

100

6E(0.75 I  AB)     =

6EI  AB   152

 

  =

 a 11.666 b (39.31) 18.489

  - 193.02   +

=

100(102)   =

6E(0.75 I  AB)

100(102)

 a 15   b a 6 (0.75 ) b 6EI  AB 2

E

128 k # t

  =

218 k # t

 a 11.666 b ( - 39.31) 18.489

  =

 a 11.666 b ( - 50.55) 18.489

  =

  - 206.46   +

 a 11.666 b (50.55) 18.489

  =

  - 103.22   +

 a 11.666 b (75.28) 18.489

206.46   +



 I  AB

 

=

 

59.26 k # t

18.489 k

 a 11.666 b (49.28) 18.489

193.02   +

102

 

  =

  - 218 k # t

Ans.

Ans.

Ans.

175 k # t

Ans.

  - 175 k # t

Ans.

  - 55.7 k # t

Ans.

Ans. M  AB

  =

  =

BA M  M BC  M CB M CD M DC 

  =

  =

  =

  =

128 k # t

#

  218 - 218k kt# t 175 k # t   - 175 k # t   - 55.7 k # t

5 52

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

Determine the moments at joints B and C , then draw the moment diagram or each member o the rame. The supports at A and D are pinned. EI  is  is constant. 11–25.

8k  

B

 



12 ft

 A

5 ft

Solution K  AB

  =

  K CD CD

  =

3EI  L  

(DF) AB

  =

(DF)DC 

(DF)BC 

  =

(DF)CB

(FEM)BA 3EI  L2

 

=

  =

3EI    K BC  BC  13

=

 

1 (DF)BA

  =

 



  =

 

  =

=

(DF)CD

>

2EI  5   =

3EI  13   + 2EI  5

(FEM)CD

100

4EI  10

  =

  =

2EI    5

26   41

>100 k # t; >

  =

1 900   3EI 

From the geometry shown in Fig. b,  BC 

  =

5 5      +    13 13

  =

10    13

Thus, (FEM)BC 

  =

(FEM)CB

 -

  =

=

 -

6EI  BC    L2BC 

a 1013 b a 16900  b 3

6EI 

EI 

2

10

 

=

>

3EI  13

  =

  - 260 k # t

>

>

3EI  13   + 2EI  5

  =

15   41

 

10 ft

D

5 ft

553

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

11–25.

(Continued)

Moment Distribution. For For the rame with P acting at C, Fig. a,

Joint

 

A

Member

 

AB

BA

DF

1

15 41

26 41

FEM

0

 

-2 0

Dist.

B

>

10 0

BC

58.54

CO Dist.

 

- 18.5

Dist.

5.89

CO

 

CO Dist.

-2 0

10 1.46

10 1.46

50.73

50.73

100

DC  

1 0

58.54

  - 32.17   - 32.17   - 18.5 10.20

10.20

5.10

5.10

 

- 3.23   - 1.87

  - 1. 2 1.03

 

0.59

- 1. 2 1.03

- 0.19 0.06

CO

 

- 0.02 0

5.89

 

0.51

Dist.

a M 

 

>

15 41

- 3.23

CO

Dist.

>

26 41

CD

- 1.87

CO Dist.

>

CB

D

  - 16.09   - 16.09

CO

Dist.

C

0.59

0.51

- 0.32

 

- 0.32   - 0.19

  - 0.16

 

- 0.16

0.10

0.10

0.05

0.05

- 0.03

 

0.06

- 0.03   - 0.02

144.44   - 144.44   - 144.44

144.44

0

5 54

 

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11–25.

(Continued)

Using these results, the shears at  A and D are computed and shown in Fig. c. Thus, or the entire rame,

+

 F   x

  =

 

0; 24.07   + 24.07   -   P 

Thus, or P

  =

  =

8  a 48.14 b (144.44)

24.0 k # t

  =

M BC 

  =

8  a 48.14 b ( - 144.44)

  =

M CB CB

  =

8  a 48.14 b ( - 144.44)

  =

  =

  =

48.14 k

8 k,

M BA

M CD CD

 

0 P 

8  a 48.14 b (144.44)

  =

  =

Ans.

  - 24.0 k # t

Ans.

  - 24.0 k # t

Ans.

24.0 k # t

Ans.

Ans. M BA M BC  M CB CB M CD CD

  =

  =

  =

  =

24.0 k # t   - 24.0 k # t   - 24.0 k # t 24.0 k # t

555

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

4 k>ft

11–26. Determine the moments acting at the ixed supports  A and D o the battered-column rame. EI  is  is constant. 6k B

 



20 ft

 A

 

15 ft

Solution (DF) AB

  =

(DF)DC 

  =

(DF)BA

  =

(DF)CD

  =

(DF)BC 

  =

(DF)CB

0

>

 I  25

>

>

 I  25   +   I  20

  =

0.4444

  =

0.5556

Consider no sidesway sidesway.. Joint

 

A

Mem.

 

AB

DF

B BA

0

- 133.33  

29.63

Dist.

 

2.29

Dist.

 

  - 0.35

  =

(FEM)

  =

82.03

=

6k

- 0.12

0.03

 

(FEM)

 

- 0.03

- 82.03

  =

(FEM) CD

  =

0

  =

(FEM) DC 

  =

0

- 0.64 - 0.18

- 0.10  

 

- 0.05

- 0.03

82.03   - 82.03

  - 133.33 k # t

BA

 

0.06

133.33 k # t

R   + 36.15   - 36.15   - 6   =

 

- 2.29

 

0.22

- 0.06

0.03

(FEM)CB  AB

0.12

 

0.05

 

 

2.86

0.79 - 0.44

0.10

- 8.23

- 4.57

 

- 0.22

  =

 

- 1.27

 

(FEM)BC 

- 5.72

 

0.18

- 4(20)2 12

 

- 1.59

CO

a M  41.0 0

 

 

- 0.79 0.44

Dist.

- 29.63

1.59

  0.35

0

 

1.27 0.64

CO

0.4444

10.29

- 2.86

CO Dist. Dist.

R

5.72

0.5556

DC  

- 20.58   - 16.46

- 10.29

4.57

CD

37.0 4

20.58  

 

8.23

CB

- 74.08   - 59.25

- 37.04

16.46

D

133.33

74.08  

59.25

Dist.

CO

0.5556

 

Dist.

CO

BC

0.4444

FEM CO

C

 

- 41.00

20 ft

D

15 ft

5 56

 

© 2018 Pearson Education, Inc., 330 Hudson Street, NY, NY 10013. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher.

11–26.

(Continued)

(FEM) AB (FEM)BC  (FEM)CD

(FEM)BA

  =

(FEM)CB

  =

  =

 

A

Mem.

 

AB

DF

FEM   - 100

 

   

CO

  =

  =

CB

0.4444

0.5556

0.5556

- 100

Dist.

 

- 3.00

- 1.50

 

Dist. 0.42

Dist.

 

CO

6.75

6.75

- 3.75

 

- 3.75

- 1.88

 

- 1.88

- 0.12

 

  0.06

1.04

1.04

0.52

0.52

- 0.29

 

- 0.29

- 0.14 0.08

 

- 0.14 0.08

0.04

- 0.02

- 115.21   - 130.44

 

- 0.02 130.44

22.065 k   + 22.065 k 44.130 k 6 41.00   + ( - 115.21) 44.130

a

(100)(25)2 6EI 

 b

- 100  

- 0.02

=

187.5 k # t

DC  

 

0

- 100

- 38.88  

- 19.44

10.80 5.40

 

- 3.00  

- 1.50

0.84 0.42

 

- 0.23   0.06

0.04

 

 

D

0.4444

 

 

- 0.12 0.03

 

- 0.02

130.44   - 130.44   - 115.21

  =

  =

M DC 

- 0.23

 

a M 

M  AB

13.51

0.03

Dist.

187. 5

13.51

0.84

CO

  =

 

 

6EI 

CD

- 24.31   - 24.31

5.40

R

187. 5

 

(100)(25)2   =

C BC

CO

 

(20)2

BA

10.80

CO Dist.

=

  - 100 k # t

- 19.44

 

 

(20)2



(6EI )(2)(0.6) )(2)(0.6)

- 38.88   - 48.62   - 48.62

Dist.

CO

 

  - 100 k # t

=

B

0

Dist.

 

(6EI )2 )2   cos u

(FEM)DC 

Joint

- 6EI   (25)2

  =

  =

 a

  - 41.00   +

b

  =

6  a 44.130 b ( - 115.21)

25.3 k # t

  =

  - 56.7 k # t

Ans.

Ans.

Ans. M  AB M DC  DC 

  =

  =

25.3 k # t   - 56.7 k # t

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