Cullen Technical Guide 2024

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FT Timber Frame Wall Tie

FT–100

Tested Values

Compression

Y m

Tension

Y m

Nail end (as received) (24mm movement)

522 504

756 (nail withdrawal)

1.3

1.15 (buckling of tie)

840

Masonry end

1417

1.15 (buckling of tie – steel failure)

943 (masonry withdrawal)

3

Based on the following criteria the following calculations have been done:

In the following examples a factored windload of 1.65kN/m 2 is suggested

Partial factor for variable action Combined pressure coefficient

1.5 1.1

Peak velocity pressure

= 1.0 kN/m 2 = 1.65 kN/m 2

Applied wind load on gable panel

= 1.5 x 1.1 x 1.0

Failure

Test Result (kN)

Y m

kmod

Result x kmod / Y m (kN)

Compression

0.504 0.756 0.943 1.417

1.15

0.9 0.9 0.9 0.9

0.3944 0.5234 0.2829 1.1090 0.2829

Tension Tension

1.3

3

Compression

1.15

*A short term action (kmod value – 0.9) has been used. An instantaneous action (kmod value – 1.1) may be used.

Maximum net surface wind pressure for the FT–100

Product Code

Vertical Tie Spacing (mm)

225

300

375

450

Stud Centres (mm)

600

600

600

600

Maximum Net Surface Wind Pressure

kN/m 2

ties/m 2

kN/m 2

ties/m 2

kN/m 2

ties/m 2

kN/m 2

ties/m 2

FT–100

2.09

7.4

1.56

5.5

1.24

4.4

1.05

3.7

1000/225 = 4.4444 4.4444x(1000/600) = 7.4 ties/m 2

1000/300 = 3.3333 3.3333x(1000/600) = 5.5 ties/m 2

1000/375 = 2.6666 2.6666x(1000/600) = 4.4 ties/m 2

1000/450 = 2.2222 2.2222x(1000/600) = 3.7ties/m 2

Lowest failure (with Ym & kmod applied)

0.2829 x 7.4 = 2.09kN/m 2

0.2829 x 5.5 = 1.56kN/m 2

0.2829 x 4.4 = 1.24kN/m 2

0.2829 x 3.7 = 1.05kN/m 2

Peak velocity pressure (kN/m 2 )

1.27

0.94

0.75

0.63

Based on the above values this could be worked backwards Provide a maximum wind load for 3.7 ties/m 2 = (1.05/1.1/1.5) = 0.63kN/m 2 peak velocity pressure

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