Cullen Technical Guide 2025

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FT-125-150 Timber Frame Wall Tie

FT–125-150

Tested Values

Compression (kN)

Y m

Tension (kN)

Y m

Nail end (as received)

0.551 0.589

1.15 (3) (buckling of tie – steel failure) 1.15 (3) (buckling of tie – steel failure) 1.15 (3) (buckling of tie – steel failure)

0.78 (nail withdrawal) 0.79 (nail withdrawal)

1.3 (1) 1.3 (1)

(6mm movement)

Masonry end

0.51

2.66 (masonry withdrawal)

3 (2)

(1) from BS EN1995-1-1 table 2.3 connections (fixing withdrawal of tie) (2) from NA to BS EN1996-1-1 table NA.1 (mortar failure of tie) (3) from NA to BS EN1995-1-1 table NA.3 (steel buckling of tie)

Based on the criteria listed below, the following calculations have been performed:

In the included examples, a factored wind load of 1.65kN/m2 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

0.551

1.15

1.1 1.1 1.1 1.1

0.527

Tension Tension

0.78 2.66 0.51

1.3

0.66

3

0.975 0.487

Compression

1.15

*An instantaneous action (kmod value – 1.1) has been used.

Maximum net surface wind pressure for the FT–125-150

Product Code

Vertical Tie Spacing (mm)

225

300

375

450

Stud Centres (mm)

600

600

600

600

Maximum Net Surface Wind Pressure

ties/m 2

kN/m 2

ties/m 2

kN/m 2

ties/m 2

kN/m 2

ties/m 2

kN/m 2

FT–125-150

2.55

7.4

1.89

5.5

1.51

4.4

1.27

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)

0.487 x 7.4 = 3.6kN/m 2

0.487 x 5.5 = 2.67kN/m 2

0.487 x 4.4 = 2.14kN/m 2

0.487 x 3.7 = 3.7kN/m 2

Peak velocity pressure (kN/m 2 )

2.18

1.61

1.29

1.09

Based on the above values this could be worked backwards Provide a maximum wind load for 3.7 ties/m 2 = (1.8/1.1/1.5) = 1.09kN/m 2 peak velocity pressure

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