00 Contents - Hilti Svenska AB

Steel base material
The figures below show representative stress-strain curves for the tests (the plotted stress is
based on the cross section). Note that the line for the powder-actuated fasteners follows the
control test line more closely than the lines for drilled holes or self-drilling screws.
Series A
Stress [N/mm 2 ]
500
450
400
350
300
250
200
150
100
ASTM 607, Grade 50
Control Test
Selfdrilling Screws
Hilti PAFs
Drilled Holes
50
0
0 5 10 15 20 25 30 35 40
Strain [%]
Series B
15% cross-section reduction 400
20% cross-section reduction
0
0 5 10 15 20 25 30 35 40
LOAD_DEFORMATION_SERIES_A LOAD_DEFORMATION_SERIES_B
Strain [%]
1.52 11 / 2007
500
450
350
300
250
200
150
100
50
S 235
Control Test
Hilti PAFs
Drilled Holes
The test results were evaluated in terms of “Utilization” as a measure of ultimate strength.
Utilization is the ultimate load of a sample expressed as a percent of the ultimate load of the
control test. Ultimate strength results are shown in the following plots.
Series A
Utilization [%]
102
100
98
96
94
92
90
88
86
Ultimate Tensile Strength
American Grade 50 Steel
X-EDNK22
"PAF -
Holes"
Drilled Holes
Selfdrilling
Screws
Series B
84
86
0 5 10 15 20 25
0 5 10 15 20
Reduction of Cross Section [%] Reduction of Cross Section [%]
102
100
98
96
94
92
90
88
ENP2,
S235
X-EM10,
S235
X-CRM8,
S235
Drilled Holes,
S235
ENP2,
S355
Drilled Holes,
S355
Plots of the utilization versus cross-section reductions show that:
• The utilization for PAF's is clearly better than that of drilled holes or self-drilling screws.
• The hole left by a removed PAF has the same effect as when the PAF is left in place.
• Increasing the number of PAF's across a section from one to two or more has a proportionally
smaller effect on utilization than placement of the first fastener.
Stress [N/mm 2 ]
Utilization [%]
Ultimate Tensile Strength
S235 and S355