Simple Connections: If the line of action of the - - PDF document

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simple connections if the line of action of the resultant
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Simple Connections: If the line of action of the - - PDF document

Sep 14, 2023 19 likes •414 views

Bolted Connections

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SLIDE 1

1

  • Bolted Connections
  • Types of Bolts:
  • 1. Ordinary or Common bolts:
  • Classified by ASTM as A307 bolts.
  • Used in light structures subjected to static loading
  • nly.
  • 2. High strength bolts:
  • Classified by ASTM as A325, A490 bolts.
  • Have tensile strengths two or more times those of
  • rdinary bolts.
  • Used in all types of structures (static + dynamic loads)
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SLIDE 2

2

  • Simple Connections:
  • If the line of action of the resultant force to be

resisted passes through the center of gravity of the connection, each part of the connection is assumed to resist an equal share of the load.

  • Eccentrically Loaded Connections:
  • If the line of action of the resultant force to be

resisted does not act through the center of gravity of the connection.

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SLIDE 3

3

  • Failure modes:
  • 1. Shear failure of the bolts:
  • 2. Tension failure in the member :
  • Yielding
  • Fracture
  • Block shear
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SLIDE 4

4

  • 3. Bearing exerted by the bolts :
  • 3. Bearing exerted by the bolts :
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SLIDE 5

5

  • Types of bolted shear connections:
  • 1. Bearing type connections:
  • Slip is acceptable (loose in connection)
  • Load will be transferred through shear in bolts and

bearing in the connected parts.

  • 2. Slip critical connections:
  • No slippage is permitted (shear force < friction force)
  • No shear and bearing.
  • Load will be transferred through friction.
  • !
  • 1. Shear Strength:
  • f v : Shearing stress on the cross:sectional area of the

bolt.

  • Ab : Cross:sectional area of the unthreaded part of

bolt.

  • Rn : Nominal strength.
  • Fnv :Nominal shear stress.
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SLIDE 6

6

!

  • !
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SLIDE 7

7

!

  • 2. Bearing Strength:
  • Bearing strength is independent of the type of

fastener because the stress under consideration is on the part being connected rather than on the fastener.

  • !
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SLIDE 8

8

!

  • !
  • "#
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SLIDE 9

9

!

  • $#% !&
  • Check bolt spacing, edge distances and bearing in the

connection shown.

  • Bolts used A325 with threads not in plane of shear.
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SLIDE 10

10

$#% !&

  • $#% !&
  • 1. Shear strength:

= (60) ()(3/4)2 / 4 = 26.46 kips φRn = (0.75)(26.46) = 19.845 kips (for each bolt) For four bolts: φRn = (4)(19.845) = 79.38 kips

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SLIDE 11

11

$#% !&

  • 2. Bearing Strength:
  • Tension member :
  • Edge holes:
  • $#% !&
  • Other holes:
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SLIDE 12

12

$#% !&

  • Gusset Plate:
  • Edge holes:
  • $#% !&
  • Other holes:
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SLIDE 13

13

$#% !&

  • $#% !&
  • Tension Failure:
  • Yielding:
  • Φt Pn = (0.9)(36)(5)(0.5) = 81 kips
  • Fracture: …………………
  • Block shear: ……………………
  • Control (without calculating Tension failure) = 79.38

kips

  • Ru = 1.2(15) +(1.6)(45) = 90 kips
  • 79.38 < 90 kips (N.G)
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SLIDE 14

14

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SLIDE 15

15

  • $#%&
  • ¾ inch diameter, A325 bolts with threads in the shear

plane no slip is permitted, A36.

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SLIDE 16

16

$#%&

  • $#%&
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SLIDE 17

17

$#%&

  • $#%&
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SLIDE 18

18

$#%&

  • $#%&
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SLIDE 19

19

$#

  • $#
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SLIDE 20

20

$#

  • $#
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SLIDE 21

21

$#

  • $#
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SLIDE 22

22

$#

  • $#
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SLIDE 23

23

$#

  • $#
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SLIDE 24

24

$#

  • '(
  • The vertical component f the force will put the bolts in

shear, while the horizontal component will cause tension on the bolts.

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SLIDE 25

25

'(

  • Bearing Type connection:
  • '(
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SLIDE 26

26

$#% '( &

  • $#% '(

&

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SLIDE 27

27

$#% '( &

  • $#% '(

&

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SLIDE 28

28

$#% '( &

  • '(
  • Slip critical connections:
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SLIDE 29

29

$#% '( )&

  • $#% '(

)&

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SLIDE 30

30

%*!&

  • +!
  • %*!&
  • +!
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SLIDE 31

31

%*!&

  • fv : Shearing stress in each bolt.
  • %*!&
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SLIDE 32

32

%*!&

  • $#%%

+!&

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SLIDE 33

33

$#%% +!&

  • $#%%

+!&

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SLIDE 34

34

%*!&

  • ,#+!
  • %*!&
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SLIDE 35

35

%*!&

  • $#%%,#

+!&

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SLIDE 36

36

$#%%,# +!&

  • $#%%,#

+!&

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SLIDE 37

37

$#%%,# +!&

  • $#%%,#

+!&

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SLIDE 38

38

$#%%,# +!&

  • $#%-

,#+!-'&

  • Bolts are ¾ inch
  • A325 bearing with threads in plane of shear.
  • Bolts are in single shear.
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SLIDE 39

39

$#%- ,#+!-'&