Flat Strap Bridging Members in a Load-Bearing Wall

Flat Strap Bridging Members in an Exterior Load-Bearing Wall SteelSmart® System 7.0 SP2

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Verification Manual

Flat Strap Bridging Members in an Exterior Load-Bearing Wall


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Table of Contents

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

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

3. Check of Safety ......................................................................................................................... 5

3.1 Design for Axial Tensile Load ............................................................................................... 5

3.2 Design of Connections ......................................................................................................... 5

3.2.1 Design of Connection at Wall Stud .............................................................................. 5

3.2.2 Design of Connection at Anchorage ............................................................................ 6

4. Conclusion ................................................................................................................................. 6

5. Verification of SteelSmart® System .......................................................................................... 7


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1. Objective

The objective of this verification sample is to check the safety of using (2) 2” X 43 mils flat strap

plates as a typical bridging system for an exterior load-bearing wall.

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 is D + 0.75L + 0.45W

Wall height = 15 ft

Wall stud section: 800S250-54 mil, 50Ksi

Stud spacing = 16 in.

Bridging members are located @ 48 in. o.c.

Lateral bracing spacing is considered equal to the bridging members spacing

Torsional bracing spacing is considered equal to the bridging members spacing

Bridging members are anchored at 16 ft

Wind load intensity (Iw) = 30 psf

Dead load = 2600 lbs

Live Load = 3800 lbs


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2. Modeling using SteelSmart® System


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3. Check of Safety

3.1 Design for Axial Tensile Load

Pall-br = allowable tensile strength of the two strap plates

= 4.75 kips

Pact-stud = axial force in the wall stud for the (D + 0.75L + 0.45W) load combination

= 2600 + 0.75*3800 = 5450 lbs = 5.45 kips

Pact-sb = actual axial tensile force in single braces of the two strap plates

=

st

wlwstud-act

D

m(B.S)(S.S)(S.F)1.5I2P0.02 (Section B3.1 – AISI S211-07)

=

8

0358.161480.45144000

301.5

245.50.02 = 0.137 kip

Pact-anchorage = total axial tensile force in the two strap plates at anchorage

= Pact-sb(L/ Stud Spacing), where L is the distance of anchorage of bridging members

= 0.137*(16*12/16) = 1.64 kips < (Pall = 4.75 kips) Safe members

3.2 Design of Connections

3.2.1 Design of Connection at Wall Stud

Vall-sc = allowable shear strength of #10 screw used for connection of the single strap plate to

the wall stud

= 0.501 kip

Vact-sc = actual shear force on the required #10 screws connecting the single strap plate to the

wall stud

= Pact-sb/2

= 0.137/2 = 0.069 kip

N = required number of #10 screws for connection of single strap plate to wall stud

= Vact-sc/ Vall-sc

= 0.069/0.501 = 2 (minimum)

Vall-sc = allowable shear strength of the required quantity of #10 screws used for connection of

the single strap plate to the wall stud

= 0.501*2 = 1.002 kips

Act/All = Vact-sc/Vall-sc

= 0.069/1.002 = 0.069


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3.2.2 Design of Connection to Anchorage Stud

Assume the anchorage stud of same thickness as that of the typical wall stud;

Vall-sc = allowable shear strength of #10 screw used for connection of the single strap plate to

anchorage stud

= 0.501 kip

Vact-sc = actual shear force on the required #10 screws connecting the single strap plate to

anchorage stud

= Pact-anchorage/2

= 1.64/2 = 0.82 kips

N = required quantity of #10 screws for connection of single strap plate to anchorage stud

= Vact-sc/ Vall-sc

= 0.82/0.501 = 2 (minimum)

Vall-sc = allowable shear strength of the required quantity of #10 screws used for connection of

the single strap plate to anchorage stud

= 2*0.501 = 1.002 kips

Act/All = Vact-sc/Vall-sc

= 0.82/1.002 = 0.820

4. Conclusion

It is safe to use *(2) 2” X 43 mils strap plates connected by 4#10 screws to wall stud (2#10 screws

per plate) and by 4#10 screws to anchorage stud (2#10 screws per plate)] as a bridging system

for this load-bearing wall.


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5. Verification of SteelSmart® System

Flat Strap Bridging Members in a Load-Bearing Wall

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