Unlock document.
This document is partially blurred.
Unlock all pages and 1 million more documents.
Get Access
CHAPTER 5 -BEAMS
5.2-1
(a) Flange area 0. 57. 53. 75 in.2
3. 75 3. 188 6. 682 in.
ZA
2a3. 75 3. 18826. 68292. 72 in.3
8. 5 0. 5 80. 93 in.3
5.2-2
(a) Area above PNA Area below PNA
web 1.750 2.334 4.085
∑A
7. 750 4. 334 in.
web 4.250 5.667 24.08
∑A
7. 750 8. 337 in.
Plastic moment:
web 3.000 0.09380 0.2814
bot. fl 1.750 1.750 3.0625
∑A
7. 750 1. 592
5.2-3
ForthecentroidofhalfofaW1850, use the centroid of a WT9 25:
5.2-4
ForthecentroidofhalfofanS1035, use the centroid of a ST5 17.5:
5.4-1
0. 38 E
Fy
bf
2tf
≤1. 0 E
Fy
0. 38 29000
60 bf
2tf
≤1. 0 29000
60 8. 35 bf
2tf
≤22. 0
The following shapes meet these criteria and are noncompact for
0. 376 29000
60 h
tw≤5. 70 29000
60 82. 7 h
tw≤125
5.4-2
(a) The flange is noncompact for flexure when
0. 38 E
bf
≤1. 0 E
0. 38 29000
65 bf
2tf
≤1. 0 29000
65 8. 03 bf
2tf
≤21. 1
3. 76 E
Fy
h
tw≤5. 70 E
Fy
3. 76 29000
65 h
tw≤5. 70 29000
65 79. 4 h
tw≤120
5.4-3
tw
11.6
Let 74. 8 5. 7 E
Fy
5. 7 29000
Fy
Fy168 ksi
5.5-1
2tf
0. 38 E
Fy
0. 38 29, 000
50 9. 15 5. 86 ∴the flange is
1. 20. 077302
81. 6P30
40. 90407, Solution is: 29. 66
b
0. 077302
5.5-2
2tf
0. 38 E
Fy
0. 38 29, 000
50 9. 15 7. 11 ∴the flange is
h
3. 76 E
(for all shapes in the Manual for Fy≤65 ksi),
1. 2wD1. 62wD19. 94, Solution is: wD4. 532
13. 60 −0. 149 13. 4 kips/ft
w13. 4 kips/ft in addition to the beam weight
13. 26 −0. 149 13. 1 kips/ft
w13. 1 kips/ft in addition to the beam weight
5.5-3
Verify that this shape is compact. For the flange,
p0. 38 29, 000
6. 89 p∴flange
15'-0" 25'-0"
1.2(40) = 48 k
0.9091"
4 k
52 k
118 k
Design strength bMn0. 9014421298 ft-kips
Mu11815. 91−4. 415. 912/2 −480. 9091
1277 ft-kips 1298 ft-kips (OK)
40'-0"
15'-0" 25'-0"
40 k
3k/ft
-75 k
40 k
85 k
Allowable strength Mn
1442
5.5-4
Verify that this shape is compact. For the flange,
p0. 38 29, 000
50 9. 15, bf
2tf
6. 31 p∴flange
-36 k
54 k
90 k 90 k
[5-11]
© 2018 Cengage Learning®. All Rights Reserved. May not be scanned, copied or duplicated,
or posted to a publicly accessible website, in whole or in part.
Maximum negative Ma−662/2 −108 ft-kips
5.5-5
Verify that this shape is compact. For the flange,
h
3. 76 E
(for all shapes in the Manual for Fy≤65 ksi),
1. 6812. 8 kips
Reaction at C:
ABC
D
25.43 k 24.42 k
-9.598 k
-24.41 k -25.42 k
Maximum moment occurs at C. Using areas of the shear diagram,
Mc0−11. 62 10. 61
214−25. 43 24. 42
214−505
12 k 8 k
0.060 k/ft
6.84 k
R
C
BCD
Reaction at C:
16.52
k
15.68
k
7.68 k
5.5-6
(a) For a W12 30, A8. 79 in.2,d12. 3 in., tf0. 440 in.,
Sx38. 6 in.3,Iy20. 3 in.4,ry1. 52 in., J0. 457 in.4,CW720
Sx
38. 6 3. 132 in.2
rts 3. 132 1. 770 in.
(rts can also be found in the dimensions and properties tables.
Lr1. 95rts E
0. 7Fy
Jc
Sxho
Jc
Sxho
E
1. 951. 76929000
0. 750
0. 4571. 0
38. 611. 860. 4571. 0
38. 611. 86
6. 76 0. 750
29000
187. 2 in. 15. 6 ft
Lp5. 37 ft, Lr15. 6 ft
[5-15]
© 2018 Cengage Learning®. All Rights Reserved. May not be scanned, copied or duplicated,
or posted to a publicly accessible website, in whole or in part.
15. 6 −5. 37
1791 in.-kips Mp
b
5.5-7
Verify that this shape is compact. For the flange,
p0. 38 29, 000
50 9. 15, bf
2tf
5. 01 p∴flange
Sx
78. 8 2. 496 in.2
rts 2. 496 1. 580 in.
(rts can also be found in the dimensions and properties tables. For a
Lr1. 95rts E
0. 7Fy
Jc
Sxho
Jc
Sxho
E
1. 951. 58029000
0. 750
1. 221. 0
78. 817. 501. 221. 0
78. 817. 5
6. 76 0. 750
29000
164. 4 in. 13. 70 ft
13. 70 −4. 557
5.5-8
Verify that this shape is compact. For the flange,
p0. 38 29000
65 8. 03, bf
2tf
4. 71 p∴flange is
compact
Lr1. 95rts E
0. 7Fy
Jc
Sxho
Jc
Sxho
E
1. 952. 04729000
0. 765
3. 491. 0
12717. 693. 491. 0
12717. 69
6. 76 0. 765
29000
195. 7 in. 16. 31 ft
For Lb9ft,LpLbLr,so
16. 31 −5. 267
5.5-9
(a) RARB300
2. 5150037504150037501. 316
Cb1. 32
2. 5Mmax 3Ma4Mb3Mc
12. 51501
2. 515013750. 5415013750. 51. 316
5.5-10
(a) Using service loads,
RARB300
2. 5150033754750311251. 667
Cb1.67
(b) Using factored loads,
2. 5Mmax 3Ma4Mb3Mc
12. 52400
