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FT Timber Frame Wall Tie
FT–50
Tested Values
Compression
Y m
Tension
Y m
Nail end (as received) (24mm movement)
1057
648 (nail withdrawal)
1.3
612 954
1.15 (buckling of tie)
690
Masonry end
1.15 (buckling of tie – steel failure)
1836 (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
0.612 0.648 1.836 0.954
1.15
0.9 0.9 0.9 0.9
0.4790 0.4486 0.5508 0.7466 0.4486
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–50
Vertical Tie Spacing (mm)
225
300
375
450
Stud Centres (mm)
Product Code
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–50
3.32
7.4
2.47
5.5
1.97
4.4
1.66
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)
0.4486 x 7.4 = 3.32kN/m 2
0.4486 x 5.5 = 2.47kN/m 2
0.4486 x 4.4 = 1.97kN/m 2
0.4486 x 3.7 = 1.66kN/m 2
Peak velocity pressure (kN/m 2 )
2.01
1.50
1.20
1.01
Based on the above values this could be worked backwards Provide a maximum wind load for 3.7 ties/m2 = (1.66/1.1/1.5) = 1.01kN/m2 peak velocity pressure
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