Connections 4

8/12/2019 Connections 4

1/104

1

SESSION 4

FRAMING (SHEAR)

CONNECTIONSCONTINUED


2/104

2

Bolted / Bolted Double Angles

114"

3"3"

11

4

"

W14x30 A992

tw = 0.27 in.12"

1

2

"3"

2L 5 x 3 x 5/16 x 0'-8 1/2A36

3/4 A325-N Bolts


3/104

3

Bolted / Bolted Double Angles

Eccentricity not considered in these

connections

No New Limit States


4/104

4

Bolted / Welded Double Angles

2L 3 x 3 x 5/16 x 0'-8 1/2"

W14x30

A992tw = 0.27 in.

A36

81

2

"

2"

4"

Return@ Top

1/4"3/4 A325-N BoltsE70XX

Knife Connection


5/104

5


Knife Connection

Beam to Column Flange

Bottom Cope to Permit Erection

New Limit States:

Coped Beam Web Strength at

Tension Flange

Weld Strength on OSLs (OutStanding Legs)


6/104

6


Coped Beam Web Strength at

Tension Flange

Vn = b Fy Snet / eb = 0.9

Snet from Table 9-2

4"

2"

W14x30


7/104

7

Vn /2

L/6

e

L

CL

Web

O

Tension, ft

Bolted / Welded Double AnglesWeld Strength on OSLs(use elastic method of analysis)


8/104

8


(((( ))))

2

nt

nt

o

nv

L

eV1.8f

e2

VL

3

2L

6

5f

2

1

0M

L2Vf

====

====

====

====

Vn /2

L/6

e

L

CLWeb

O

Tension, ft


9/104

9


22

2

n

22

2

n

2

v

2

tw

e12.9L

D)(1.392L2V

e12.9LL2

V

fff

++++====

++++====

++++====

Vn /2

L/6

e

L

CLWeb

O

Tension, ft


10/104

10

Bolted / Welded Double AnglesExample: Calculate Vn based on the weld

fracture strength of the OSLs

e = 3 + 0.27/2 =3.135 in.

L = 8.5 in.

3/4 A325-N Bolts

E70XX

2L 3 x 3 x 5/16 x 0'-8 1/2"

W14x30A992tw = 0.27 in.

A36

812"

2"

e

Return@ Top

1/4"


11/104

11

Bolted / Welded Double Angles Example

Note: Weld returns at top of angles have

been neglected

k57.0

(3.135)12.95.8

4)(1.392(8.5)2

e12.9L

D)(1.392L2

V

22

2

22

2

n

====++++

====

++++====


12/104

12

Single Plate

SHEAR TAB OR SINGLEPLATE


13/104

13

Mw = Vu ew

Mb = Vu eb

Shear Tab or Single Plate

Mw Mb

Bolt

Line

eb

ew

a


14/104

14


Rotation is obtained by

bolts plowing the

plate (bearingdeformation in plate),

which requires limiting

the plate thickness

Single Plate


15/104

15


Geometric Limitations:

tp < db /2 + 1/16

Lh > 1 1/2 in.

Lv > 1 1/2 in.2 1/2 in. < a < 3 1/2 in.

2 < n = No. of Bolts < 9

L > T/2

Plate Material: A36 Steel

a

L

Lv

2@3"

Lh


16/104

16


Eccentricities depend on:

i) Connected Element

Rigid

Flexible

ii) Hole Type

Standard Short Slots


17/104

17


Rigid Elements:

Column Flange

Girder w/ Plates on Both Sides

Concrete Wall

Flexible Elements

Girder Web on One SideNote: Not recommended for column webs.


18/104

18


Flexible Support /Standard Holes

eb = |(n - 1) a| > a

Flexible Support /

Short Slotted Holeseb = |(2n/3) a| > a

a eb

Bolt

Line


19/104

19


Rigid Support /

Standard Holes

eb = |(n - 1) a|

Rigid Support /

Short Slotted Holes

eb = |(2n/3) a|

a eb

Bolt

Line


20/104

20


Weld Strength

E70XX Electrode

Weld Size > 3/4 tp on each side

Weld size is then sufficient to develop plate

in tension yielding


21/104

21


Plate Limit States:

Shear Yielding

Shear Rupture

Block Shear

Bearing / Tear Out

Plate Buckling


22/104

22


Plate Buckling

tp > L / 64 1/4 in.

L

Compression


23/104

23


Example: Determine required plate and

weld sizes.

W14x30

tw = 0.27 in

T = 12 in.

Vu = 40 k

E70XX

3/4 in. A325-N Bolts


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24

Shear Tab or Single Plate ExampleTry 3 3/4 in. A325-N Bolts

Vn = (0.75 x 48 x 0.4418) (3)= 15.9 x 3

= 47.7 k > Vu

= 40 k

Try 1/4 in. plate

Maximum Plate Thickness= d/2 + 1/16 = 3/8 + 1/16 = 0.4375 in.


25/104

25

Plate Geometry

Check Plate

Buckling

L / 64 = 9 / 64

= 0.14 < 1/4 OK

Shear Tab or Single Plate Example

2@3" 9" > T/2

112"

112"

3" 112"


26/104

26

Check bolts for eccentric loading:

Rigid Support / Standard Holes

eb = |(n - 1) a| = |(3 1) 3| = 1.0 in.

Using Table 7-17 with

s = 3 in. ex = 1.0 in. n = 3

By extrapolation: C = 2.71



27/104

27

Table 7-17


28/104

28

Vn = C x rv= 2.71 x 15.9

= 43.1 k > Vu = 40 k OK



29/104

29

Plate Limit States

t = 1/4 in.

Shear Yielding:

Vn = 0.9 (0.6 Fy) Ag= 0.9 (0.6 x 36) (0.25 x 9)

= 43.7 k > 40 k OK



30/104

30

Shear Fracture:

Vn = 0.75 (0.6 Fu) An = 41.6 k OKBlock Shear: 44.8 k OK

Bearing: 53.4 k OK

Use PL 1/4 x 4 1/2 x 0-9 A36

with (3) 3/4 in. A325-N Bolts

(see also Table 10-9)



31/104

31

Required Weld Size

tweld = 3/4 (1/4) = 3/16 in.

Notes: - Min. weld requirements maycontrol (depends on column

flange thickness)

- Beam web (tw = 0.27 in.) will notcontrol bearing



32/104

32


11

2

"

2@3"

11

2

"

112"

9"

3"

3/16

PL 1/4 x 4 1/2 x 0'-9"


33/104

33

SINGLE ANGLECONNECTIONS

Bolted and Welded Alternatives

One Angle

Horizontal short slots

may be used in angle@ TopReturn


34/104

34

Eccentricity Assumptions for OSL

Single Row Double Row

Single Angle Connections

ea=ebb

e a

CL Web CL Web

Bolts

Angle


35/104

35

Eccentricity Assumptions for OSL

Welded


e w2 tweldReturn

CL Web

+

c.g.weld


36/104

36


Notes:

Eccentricity is ignored on the beam side

when the connection is a single row.

Standard holes or short slots can be usedon the beam side.

Only standard holes should be used on

the supporting member side.


37/104

37


Additional Limit States for Bolted

Connections

Flexural Yielding

Vn = 0.9 Fy Sg / eaS

g

= tp

L2/6

L

ea


38/104

38


Flexural Fracture

Vn = 0.75 Fu Snet / ea

Snet:

See LRFD Manual, Table 15-2

L

ea


39/104

39

Table 15-2


40/104

40

Eccentric Shear of Bolt Group

(Instantaneous Center of Rotation Method)

Table 7-17 Table 7-18Vn = C (rv)

VnVn



41/104

41


Bearing

Vn = C (rvb)

where rvb is the bearing strength at theoutermost bolt


42/104

42


db (in.) Min. t (in.)

3/4 3/8

7/8 3/8

1 1/2


43/104

43

Additional Limit States for WeldedConnections

Eccentric Shear Strength of Weld

Table 8-11

2 tweldReturn

Vn Vn



44/104

44

Table 8-11


45/104

45

Welded Unstiffened Seat

Connections

StabilizingAngle

L4x4x1/4

AlternateLocation


46/104

46

Welded Unstiffened Seat

ConnectionsLimit States:

Beam Local WebYielding

Beam Local Web

Crippling Seat Angle Bending

Seat Angle Shear

Yielding

Weld Fracture


47/104

47

Beam Local Web Yielding

N+2.5k

N


48/104

48

Beam Local Web Yielding

Section K1.3Web Local Yielding

= 1.0R

n= (2.5kdesign + N)Fyw tw

N+2.5k

N


49/104

49

Beam Local Web Crippling


50/104

50

Beam Local Web CripplingSection K1.4 Web Local Crippling Force @


51/104

51

Design Model for Angle Flexure

The N-distance is

determined from the

limit states of web

yielding and webcrippling, but not less

than kdetailing.

34"

N

Critical Section

for Bending, Shear

Supported Beam

Supporting Column

ra = 3/8"

t a


52/104

52


Setback = 1/2 in.

Beam Tolerance = 1/4 in.

Use 3/4 in. setbackin calculations

34

" N

Critical Section

for Bending, Shear

Supported Beam

Supporting Column

ra = 3/8"

t a


53/104

53


The maximum value of

N is then used to

determine theeccentricity:

e = N/2 + (3/4 3/8) ta= N/2 + 3/8 -ta

34

" N

Critical Sectionfor Bending, Shear

Supported Beam

Supporting Column

ra = 3/8"

t a


54/104

54


For the Limit State of Web Yielding

designwy

u

min k5.2tF0.1

R

N ====

D i M d l f A l Fl


55/104

55


For the Limit State of Web Crippling

when N/d < 0.2

when N/d > 0.2

++++

==== 0.2

t

t1

tF

t

)(68t0.75

R

4

dN

1.5

w

f

fy

w

2

w

umin

5.1

w

f

fy

w

2

w

umin

t

t1

tF

t

)(68t0.75

R

3

dN

====


56/104

56


Required angle thickness

from OSL bending

with La = angle lengthe = N/2 + 3/8 - ta

ay

ureq

LF9.0eR4t ====

34

" N

Critical Section

for Bending, Shear

Supported Beam

Supporting Column

ra = 3/8"

t a


57/104

57

Angle Shear Yielding

Therefore

angleaynu tL)F6.0(9.0RR ====

ay

ureq

L)F6.0(9.0

Rt ====


58/104


59/104

Stiffened Seated Connections


60/104

60

4"

Alternate

Clip Position

StabilizerClip

Seat Plate

StiffenerOptionalTrim Lines

2"



61/104

61

Stiffened Seated ConnectionsLimit States:

Beam Web Yielding Beam Web Crippling

Strength of Stiffener Plate

Eccentric Shear of Connecting Side Weld

or Bolts

Column Web Failure


62/104

62


Notes:

1/2 in. setback but 3/4 in. for calculations

Seat plate > 3/8 in.

For unstiffened beam webs, the seatstiffener thickness is a function of the

beam and seat stiffener yield stresses and

the weld size.


63/104

63

Stiffened Seated ConnectionsFor Unstiffened Beams:

Seat Stiffener

Beam, Fy Fy ts36 36 tw

50 36 1.4 tw50 50 tw

For Stiffened and Unstiffened BeamsSeat Stiffener: ts (36 ksi) > 2 tweld

ts (50 ksi) > 1.5 tweld


64/104

64


Column Web Failure

Stress concentration requires stiff web.

Stress Concentration


65/104

65

Column Web Failure

Also need to prevent flange rotation.



66/104

66


LRFD has a simplified approach

for sections heavier than:

43 lb/ft for W14 ( > W14x43)

40 lb/ft for W12 ( > W12x40)

30 lb/ft for W10 ( > W10x30)

24 lb/ft for W8 ( > W8x24)


67/104

67

Stiffened Seated ConnectionsRules:

Beam must be bolted to seat with A325 orA490 bolts within the greater of W/2 or

2 5/8 in. from the column web.

Special rules for W14x43

Seat plate is not welded to the beam

Weld size is limited to shear yieldstrength of the column web



68/104

68



69/104

69

AdditionalDesign Examples



70/104

70

Single Angle ConnectionsExample: Is the connection adequate?

W21x50A992

tw = 0.38 in.

Vu = 90 k

Vu = 90 k

112"

2"

112"

4@3"

3"

3"

3"

134"114

"

OSL

L8 x 6 x 3/8 x 1-3 A36

3/4 in.

A325N Bolts

Single Angle Connection Example


71/104

71


Angle Flexural Yield

Supporting Side OSL Controls

Vn = 0.9 Fy Sg / eaSg = (3/8) (15.0)

2 / 6 = 14.06 in3

ea = 0.38 / 2 + 3 = 3.19 in.

Vn = 0.9 Fy Sg / ea

= 0.9 (36) (14.06) / 3.19= 142.9 k > 90 k OK

Vu

a


72/104


73/104

73

Table 15-2



74/104

74

Vn = 0.75 Fu Snet / ea= 0.75 (58) (10.1) / 3.19

= 137.7 k > 90 k OK

g g p



75/104

75

Bolt Fracture

eb

= 0.38 / 2 + 3 + 1.5 = 4.69 in.

Table 7-18

n = 5 b = 3 in. s = 3 in.

By interpolation: C = 6.29

g g p

Vu

eb

3"

3"

Table 7-18


76/104

76



77/104

77

3/4 in. A325-N

rv = 0.75 x 48 x 0.4418= 15.9 k

Vn = C (rv) = 6.29 x 15.9= 100 k > 90 k OK



78/104

78

Bearing

Critical Bolts

Elong. = 2.4 (58) (3/4 x 3/8)

= 39.2 k

T.O. = 1.2 (58) (1.5 13/32) (3/8)

= 28.5 k

rbv = 0.75 (28.5)= 21.4 k > rv = 15.9 k OK

Vu

g g p



79/104

79

Beam Web

tw = 0.38 in > 3/8 in.

will not control

Connection is adequate if supporting

element thickness is

> (15.9 / 39.2) (3/8) = 0.15 in.

Single Angle Design Example


80/104

80

Example: Outstanding leg of previous

connection welded. Determine required

weld size. Column, tf= 0.710 in.2 t weldReturn

Vu = 90 k

E70XX

L6 x 6 x 3/8 x 1'-3"



81/104

81

Table 8-11 with l = 15 in.

kl = 6 in.k = 6 / 15 = 0.4! x = 0.057

xl = 0.057 x 15 = 0.855 in.al = 0.38/2 + 6 0.855

= 5.34 in.

a = 5.34 / 15 = 0.356

g g p

15"

0.19"

al

xl

Vu = 90 k

Table 8-11


82/104

82



83/104

83

C = 1.64 by interpolation

Dreqd

= Vu

/ (C C1

l)

= 90 / (1.64 x 1.0 x 15)

= 3.65! 4/16 = 1/4 in.

Min. weld = 1/4 in. (Column tf= 0.710 in.)

Max weld = 5/16 in.Use 1/4 in. Fillet weld

g g p

Unstiffened Seat Connection Ex.


84/104

84

W18x46 A992

W14x90 Column

L4 x 4 x 5/8 x 0'-8"

?

0.440"

Vu = 35 k

WebCL

W18x46

bf= 6.06 in.t f= 0.605 in.d = 18.06 in.tw = 0.360 in.

kdetailing = 1 1/4 in.kdesign = 1.01in.

Example:


85/104

85


Example: Determine

(1) if seat angle is adequate, and

(2) required weld size.

A36 Angle E70xx Electrode


86/104

86


For the Limit State of Web Yielding

design

wy

umin k5.2

tF0.1

RN ====

01.1x5.2360.0x50x0.1

35 ====

detailingk58.0


87/104

87

Unstiffened Seat Connection Ex.For the Limit State of Web Crippling

assuming N/d < 0.25.1

w

f

fy

w

2

w

umin

t

t1

tF

t

)t68(75.0

R

3

dN

====

5.1

2360.0

605.01

605.0x50

360.0

)360.0x68(75.0

35

3

06.18

====

in.5.5====



88/104

88

For the Limit State of Web Crippling,

N = -5.5 in. < kdetailing

Therefore

N = kdetailing = 1.25 in.

Check

N/d = 1.25/18.06 = 0.069 < 0.2 OK



89/104

89

Required angle thickness from OSL bending

e = N/2 + 3/8 ta= 1.25/2 + 3/8 5/8

= 0.375 in.34"

N

Critical Sectionfor Bending, Shear

Supported Beam

Supporting Column

ra = 3/8"t a



90/104

90

With La = 8 in.

= 0.45 in. < 5/8 in. OK

ay

ureq

LF9.0eR4t ====

0.8x36x9.0

375.0x35x4====

U tiff d S t C ti E


91/104

91

Unstiffened Seat Connection Ex.Required angle thickness from

OSL Shear Yielding:

ay

ureq

L)F6.0(9.0

Rt ====


92/104

92

Determine required weld size.

Using Table 8-5 withangle = 0 degrees

k = 0.0

e = 3/4 + N/2 = 3/4 + 1.25/2 = 1.375 in.

a = e/L = 1.375/4.0 = 0.344

Find C = 2.18

Unstiffened Seat Connection Ex.Table 8 5


93/104

93

Table 8-5



94/104

94

Dmin = Ru/CC1L = 35/(2.18x1.0x4.0)

= 4.0 1/16ths

Min. Weld = in.

Use in. fillet weld both sides of angle legs.

Returns at top.

Unstiffened Seat Connection Ex.CL


95/104

95

WebCL

W18x46 A992

L4 x 4 x 5/8 x 0'-8"

1/4

W14x90 Column

0.440"

Vu = 35 k

Stiffened Seat Example

Determine: 1 A36 stiffener thickness


96/104

96

Determine: 1. A36 stiffener thickness

2. E70XX weld size.

W24x68A36

t wb = 0.415 in.

t wc

W14x90A992= 0.440 in.

W

Lt s

Ru = 80 k



97/104

97

W14x90 Satisfies column web requirement.

W24x68A992

t wb = 0.415 in.

t wc

W14x90A992= 0.440 in.

W

Lt s


Web Crippling


98/104

98

Web Crippling

Using Table 9-5 assuming N/d < 0.2

Check N/d = 1.20 / 23.73 = 0.05 < 0.2 OK

in.88.10.7513.10.7559.5

7.7380

setback4

3min

=+=+=

+

=R

RRW

u

W b Yi ldi



99/104

99

Web Yielding

Use W = 4 in. and t = 3/8 in.

Bolt location rule will be satisfied.

in.17.10.75418.00.75

8.20

3.7180

setbackR

RR

W 2

1u

min

====++++====++++====

++++

====



100/104

100

With: W = 4 in.

1/4 in. Weld

Using Table 10-8:L = 10 in.

Rn = 82.3 > Ru = 80 k

34"

Ru = 80 k

10"

4"



101/104

101

Table 10-8



102/104

102

Column Web Strength at Weld:

Rn = 0.9 (0.6 Fy) L twc x 2

= 0.9 (0.6 x 50) (10) (0.440) (2)= 237.6 k > 80 k OK



103/104

103

Stiffener Plate (W24x68 twb = 0.415 in.)

ts (36 ksi) > 1.4 twb (50 ksi)> 1.4 x 0.415 = 0.581 in.

ts > 2 tweld = 2 x 1/4 = 1/2 in.

Use 5/8 in. plate



104/104

104

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