connection of header to jamb by stiffclip al

8/18/2019 Connection of Header to Jamb by StiffClip AL

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Connection of Header to Jamb by (2) StiffClip AL600 SteelSmart® System 7.0 SP2

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Verification Manual

Connection of Header to Jamb by

(2) StiffClip AL600


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Table of Contents

1. Objective .................................................................................................................................. 3

2. Modeling using SteelSmart® System ....................................................................................... 4

3. Header Connection to Jamb .................................................................................................... 6

3.1 Applied Forces.................................................................................................................. 6

3.2 Check of Clip Strength ...................................................................................................... 6

3.3 Design of Short Leg Connection to Header ...................................................................... 7

3.3.1 Design Forces ........................................................................................................... 7

3.3.2 Allowable Shear Strength of Individual Screw ........................................................ 7

3.3.3 Allowable Tensile Strength of Individual Screw ...................................................... 8

3.3.4 Check of Safety ........................................................................................................ 9

3.4 Design of Long Leg Connection to Jamb .......................................................................... 9

3.4.1 Design Forces ........................................................................................................... 9

3.4.2 Allowable Shear Strength of Individual Screw ...................................................... 10

3.4.3 Allowable Tensile Strength of Individual Screw .................................................... 11

3.4.4 Actual Tensile Force on Critical Screw due to Mact-x .............................................. 12

3.4.5 Actual Tensile Force on Critical Screw due to Mact-y .............................................. 13

3.4.6 Check of Safety ...................................................................................................... 14

4. Conclusion ............................................................................................................................. 14

5. Verification of SteelSmart® System ....................................................................................... 15

5.1 Clip Strength .................................................................................................................. 15

5.2 Screwed Connections of Short and Long Legs of Clip to Header and Jamb ................... 16


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1.

Objective

The objective of this verification sample is to check the safety of the connection of the header

member to the jamb member in a window, using (2) StiffClip AL 600.

This check should be based on the following parameters:

Design Code: 2012 IBC w/ AISI S100-07/ S2-10

Design Method: ASD

Design Load Combination: D + 0.75L + 0.75W

Adjacent Stud Depth = 6 in.

Jamb Section: 600JAM250-33, 50ksi

Header Section: (2) 600JAM250-43, 50ksi + (2) 600T125-33, 33ksi

Wind Load Distribution: 2-Ways (Fixed in Header & Sill)

Stud Spacing = 16 in.

Wind Load (W) = 24 psf

Dead Load (D) = 100 lbs/ft

Live Load (L) = 150 lbs/ft

Wall Height (LJ) = 10 ft

Window Width (Ww) = 6 ft

Window Height (HW) = 4 ft

Distance from Left Stud = 0

Sill Height (HS) = 3 ft

Figure 1 shows the layout of this connection.

Figure 1 Connection of Header to Jamb using (2) StiffClip AL600


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2.

Modeling using SteelSmart® System


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3.

Header Connection to Jamb

3.1 Applied Forces

The applied forces on the connection of the StiffClip AL to header shall be calculated as follows:

F2 = vertical reaction at header support due to gravity loads

=

2

*75.0W

W L D

= 2

6150*75.0100 = 0.638 kip

F3 = horizontal reaction at header support due to wind loads

=

2

*22

*75.0W

W S J W W

H H L H W

=

2

6*2

4310

2

4*24*75.0

= 0.189 kip

3.2

Check of Clip Strength

Considering the use of two clips, the clip strength shall be checked against the combination of

the applied forces F2 and F3 as follows:

OK F

F

F

F

all call c

0.1184.0015.3*2

189.0

091.2*2

638.0

3

3

2

2


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3.3

Design of Short Leg Connection to Header

3.3.1 Design Forces

Since two clips are used for the connection of the header to the jamb;

(1)

One-half of the force F2 is assumed causing direct tension on the screws connecting the

short leg of the upper clip to the header, and the other half is assumed transferred to the jamb directly by bearing, i.e.

Tact = actual tensile force on screws connecting the short leg of the upper clip to the header

=2

2 F

=2

638.0 = 0.319 kip

(2)

The force F3 is assumed divided equally on the two clips as direct shear force on the screws

connecting the short leg of the clip to the header, i.e.

Vact = actual shear force on screws connecting the short leg of each clip to the header

=23

F

=2

189.0 = 0.095 kip

3.3.2 Allowable Shear Strength of Individual Screw

(1)

d = #12 screw diameter

= 0.216 in.

(2)

t1 = thickness of StiffClip AL 600

= 0.0713 in.

(3)

t2 = thickness of the header’s closure track

= 0.0346 in.

(4)

Fu1 = ultimate tensile strength of StiffClip AL 600

= 65 ksi

(5)

Fu2 = ultimate tensile strength of the header’s closure track

= 45 ksi

(6)

Pss = nominal shear strength of screw as reported by manufacture’s tables

= 2.33 kips

t2/t1 = 0.0346/ 0.0713

= 0.485 < 1.0

Pns(1) = 22

13

22.4 u F d t (Eq. E4.3.1-1)

= 45*216.0*0346.0*2.4 21

3 = 0.565 kip


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Pns(2) = 117.2 udF t (Eq. E4.3.1-2)

= 65*216.0*0713.0*7.2 = 2.703 kips

Pns(3) = 227.2 udF t (Eq. E4.3.1-3)

= 45*216.0*0346.0*7.2 = 0.908 kip

Pns = least of (Pns(1), Pns(2), Pns(3))

= least of (0.565, 2.703, 0.908) = 0.565 kip

Ps-all = allowable shear strength of screw

= least of (Pns, Pss)/

= least of (0.565, 2.33)/3.00 = 0.188 kip

3.3.3

Allowable Tensile Strength of Individual Screw

(1)

d = #12 screw diameter

= 0.216 in.

(2)

d’w = effective pull-over diameter

= 0.34 in.

(3)

t1 = thickness of StiffClip AL600

= 0.0713 in.

(4)

t2 = thickness of the header’s closure track

= 0.0346 in.

(5)

tc = lesser of depth of penetration and thickness t2

= t2 = 0.0346 in.

(6)

Fu1 = ultimate tensile strength of StiffClip AL600

= 65 ksi

(7)

Fu2 = ultimate tensile strength of the header’s closure track

= 45 ksi

(8)

Pts = nominal tensile strength of screw as reported by manufacture’s tables

= 3.52 kips

Pnot = nominal pull-out strength of individual screw

=285.0 ucdF t (Eq. E4.4.1-1)

= 45*216.0*0346.0*85.0 = 0.286 kip

Pnov = nominal pull-over strength of individual screw

=1

'

15.1 uw F d t (Eq. E4.4.2-1)

= 65*34.0*0713.0*5.1 = 2.364 kips

Pnt = least of (Pnot, Pnov)

= least of (0.286, 2.364) = 0.286 kip


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Pt-all = allowable tensile strength of screw

= least of (Pnt, Pts)/

= least of (0.286, 3.52)/3.00 = 0.095 kip

3.3.4

Check of Safety

Assume using four screws;

all t

act

all s

act

P

nT

P

nV

=095.0

4319.0

188.0

4095.0 = 0.966 < 1.0

Using 4#12 screws is safe to connect the short leg of the StiffClip AL600 to the header.

3.4

Design of Long Leg Connection to Jamb

3.4.1 Design Forces

Since two clips are used for the connection of the header to the jamb;

(1)

The force F2 is assumed divided equally on the two clips as eccentric shear force on the

screws connecting the long leg of the clip to the jamb, i.e.

Vact-y = actual shear force on screws connecting the long leg of each clip to the jamb in the

vertical direction

=2

2 F

=2

638.0 = 0.319 kip

Mact-x = actual bending moment on screws connecting the long leg of each clip to the jamb

due to eccentricity of Vact-y

= eV yact , where e is the distance between the back of the jamb web and the center of

the screws connecting the short leg of the clip to the header (Figure 2)

= 75.0*319.0 = 0.239 kip-in.

Figure 2 Side View of StiffClip AL600 (all dimensions are in inches)


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(2)

The force F3 is assumed divided equally on the two clips as eccentric shear force on the

screws connecting the long leg of the clip to the jamb, i.e.

Vact-x = actual shear force on screws connecting the long leg of each clip to the jamb in the

horizontal direction

=2

3 F

=2

189.0 = 0.095 kip

Mact-y = actual bending moment on screws connecting the long leg of each clip to the jamb

due to eccentricity of Vact-x

= eV xact , where e is the distance between the back of the jamb web and the center of

the screws connecting the short leg of the clip to the header (Figure 2)

= 75.0*095.0 = 0.071 kip-in.

3.4.2

Allowable Shear Strength of Individual Screw

(1)

d = #12 screw diameter= 0.216 in.

(2)


= 0.0713 in.

(3)

t2 = thickness of jamb

= 0.0346 in.

(4)

Fu1 = ultimate tensile strength of StiffClip AL600

= 65 ksi

(5)

Fu2 = ultimate tensile strength of jamb

= 65 ksi

(6)

Pss = nominal shear strength of screw as reported by manufacture’s tables = 2.33 kips

t2/t1 = 0.0346/ 0.0713

= 0.485 < 1.0

Pns(1) = 221

3

22.4 u F d t (Eq. E4.3.1-1)

= 65*216.0*0346.0*2.4 21

3 = 0.817 kip

Pns(2) = 117.2 udF t (Eq. E4.3.1-2)

= 65*216.0*0713.0*7.2 = 2.703 kips

Pns(3) = 227.2 udF t (Eq. E4.3.1-3)

= 65*216.0*0346.0*7.2 = 1.312 kip

Pns = least of (Pns(1), Pns(2), Pns(3))

= least of (0.817, 2.703, 1.312) = 0.817 kip


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Ps-all = allowable shear strength of screw

= least of (Pns, Pss)/

= least of (0.817, 2.33)/3.00 = 0.272 kip

3.4.3

Allowable Tensile Strength of Individual Screw

(1)

d = #12 screw diameter= 0.216 in.

(2)

d’w = effective pull-over diameter

= 0.34 in.

(3)


= 0.0713 in.

(4)

t2 = thickness of jamb

= 0.0346 in.

(5)

tc = lesser of depth of penetration and thickness t2

= t2 = 0.0346 in.

(6)

Fu1 = ultimate tensile strength of StiffClip AL600= 65 ksi

(7)

Fu2 = ultimate tensile strength of jamb

= 65 ksi

(8)

Pts = nominal tensile strength of screw as reported by manufacture’s tables

= 3.52 kips

Pnot = nominal pull-out strength of individual screw

=2

85.0 ucdF t (Eq. E4.4.1-1)

= 65*216.0*0346.0*85.0 = 0.413 kip

Pnov = nominal pull-over strength of individual screw

=1

'

15.1 uw F d t (Eq. E4.4.2-1)

= 65*34.0*0713.0*5.1 = 2.364 kips

Pnt = least of (Pnot, Pnov)

= least of (0.413, 2.364) = 0.413 kip

Pt-all = allowable tensile strength of screw

= least of (Pnt, Pts)/

= least of (0.413, 3.52)/3.00 = 0.138 kip


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3.4.4

Actual Tensile Force on Critical Screw due to Mact-x

Assumptions:

(1)

Using 4 screws

(2)

All screws are in tension

The front view of the StiffClip AL600 is shown in Figure 3 on which the direction of the bending

moment Mact-x and the assumed location of the neutral axis.

Figure 3 Front View of StiffClip AL600 with Direction of Mact-x (all dimensions are in inches)

To check the correctness of assuming that all screws are in tension, and from equilibrium, the

first moment of area of the screws in tension shall equal the first moment of area of the

compressed part of the StiffClip AL600, i.e.

2

2

21

cg clip screw

Y

bY Y nA

2*875.5563.175.0375.03*216.0*

4*2

2

2 cg cg cg

Y Y Y

Ycg = 0.2466 in. < 0.688 in. (correct assumption)

Ix = moment of inertia of the screws in tension and of the compressed part of the StiffClip

AL600 about the neutral axis

= 3

2466.0*875.5563.175.02466.0375.02466.03*216.0*

4*2

3222

= 0.3377 in.

4


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Pact-Mx = actual tensile force on critical screw due to moment Mact-x

= screw

x

critical xact A

I

Y M

= 2216.0*4

*3377.0

75.02466.03*239.0 = 0.052 kip

3.4.5

Actual Tensile Force on Critical Screw due to Mact-y

Assumptions:

(1)

Using 4 screws

(2)

All screws are in tension

The front view of the StiffClip AL600 is shown in Figure 4 on which the direction of the bending

moment Mact-y and the assumed location of the neutral axis.

Figure 4 Front View of StiffClip AL600 with Direction of Mact-y (all dimensions are in inches)

To check the correctness of assuming that all screws are in tension, and from equilibrium, the

first moment of area of the screws in tension shall equal the first moment of area of the

compressed part of the StiffClip AL600, i.e.

2

2

21

cg clip screw

X h X X nA

2*3125.4875.0875.5875.0875.5*216.0*

4*2

2

2 cg

cg cg

X X X

Xcg = 0.4893 in. < 0.875 in. (correct assumption)


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Iy = moment of inertia of the screws in tension and of the compressed part of the StiffClip

AL600 about the neutral axis

= 3

4893.0*3125.4875.04893.0875.5875.04893.0875.5*216.0*

4*2

3222

= 1.6192 in.4

Pact-My = actual tensile force on critical screw due to moment Mact-y

= screw

y

critical yact A

I

X M

= 2216.0*4

*6192.1

875.04893.0875.5*071.0 = 0.007 kip

3.4.6 Check of Safety

For the most critical screw (stressed in tension due to Mact-x and Mact-y);

all t

Myact Mxact

all s

xact yact

P

P P

P

nV nV

22

=

138.0

007.0052.0

272.0

4095.04319.0 22

= 0.733 < 1.0

Using 4#12 screws is safe to connect the long leg of the StiffClip AL600 to the jamb.

4.

Conclusion

It is safe to use the (2) StiffClip AL600 for the connection of header to jamb, using 4#12 screws

for the connection of the clip’s short leg to header and 4#12 screws for the connection of the

clip’s long leg to jamb.


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5.

Verification of SteelSmart® System

5.1 Clip Strength


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5.2

Screwed Connections of Short and Long Legs of Clip to Header and Jamb

connection of header to jamb by stiffclip al

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