S-BT Threaded Fastener Specification

Specifications page75
S-BT Screw-in threaded studs
Universität Stuttgart
Institut für Konstruktion und Entwurf
Schwerpunkte: Stahlbau, Holzbau und Verbundbau
Prof. Dr.-Ing. Ulrike Kuhlmann
2017-06-30 S-BT Fatigue Page 36
9.2.3 Recommendation of a design S-N curve for ABS
ABS:2003 includes following 8 S-N curves for non-tubular details in air, see Table 9.3. The
slope intersection is at 1
∙10
7
number of cycles. In general the slope is m = 3 for curve D to W as
typical for welded details. However, for mild details (curve B and C) the slope is more shallow
with m = 3.5 to 4.
Based on the statistical evaluation of the Hilti S-BT fatigue test data according to
Table 9.1 an
additional class “S-BT” is proposed having a uniform slope of m = 5, see following
Table 9.3
and
Figure 32. According to the standard S-N curves given in ABS the slope is set to be con-
stant to m = 5 beyond N
Q
= 1∙10
7
.
Table 9.3. ABS-(A) S-N curves and new proposed S-N curve for Hilti S-BT fastener
Curve A m r N
Q
S
Q
Class for [MPa]
units
for [ksi]
units
for [MPa]
units
for [ksi]
units
for [MPa]
units
for [ksi]
units
B
1.01x10
15
4.48x10
11
4.0 1.02x10
19
9.49x10
13
6.0 1.0x10
7
100.2 14.5
C
4.23x10
13
4.93x10
10
3.5 2.59x10
17
6.35x10
12
5.5 1.0x10
7
78.2 11.4
D
1.52x10
12
4.65x10
9
3.0 4.33x10
15
2.79x10
11
5.0 1.0x10
7
53.4 7.75
E
1.04x10
12
3.18x10
9
3.0 2.30x10
15
1.48x10
11
5.0 1.0x10
7
47.0 6.83
F
6.30x10
11
1.93x10
9
3.0 9.97x10
14
6.24x10
10
5.0 1.0x10
7
39.8 5.78
F2
4.30x10
11
1.31x10
9
3.0 5.28x10
14
3.40x10
10
5.0 1.0x10
7
35.0 5.08
G
2.50x10
11
7.64x10
8
3.0 2.14x10
14
1.38x10
10
5.0 1.0x10
7
29.2 4.24
W
1.60x10
11
4.89x10
8
3.0 1.02x10
14
6.54x10
9
5.0 1.0x10
7
25.2 3.66
S-BT 1.995x10
16
1.28x10
12
5.0 1.995x10
16
1.28x10
12
5.0 1.0x10
7
72.4 10.50
10
100
10.000 100.000 1.000.000 10.000.000
Number of cycles N [-]
Nominal stress range  [N/mm
2
]
300
200
100
400
50
500
B
10
70
20



t
Hilti S-BT
C
D
F
E
A
BS
classes
welded stud
F2
G
W
Hilti S-BT fastener
(correct installed condition)
Hilti S-BT fastener
(installed and removed)
proposed design S-N curve
m =5
1
Figure 32. Comparison of Hilti S-BT fatigue test data with ABS-(A) Offshore S-N curves
and new proposed fatigue class “S-BT” for Hilti S-BT fastener
Universität Stuttgart
Institut für Konstruktion und Entwurf
Schwerpunkte: Stahlbau, Holzbau und Verbundbau
Prof. Dr.-Ing. Ulrike Kuhlmann
2017-06-30 S-BT Fatigue Page 44
10.2.3 AWS D1.1/D1.1M:2015
It is recommended to use the following design S-N curve respectively stress category termed
“S-BT” given in
Table 10.2 for the constructional detail “Steel base material with Hilti S-BT
screw-in threaded studs”.
Table 10.2. Recommendation of fatigue S-N curve and stress category according to AWS D1.1:2015
Description and requirements
Stress
Category
Constant
C
f
ksi [MPa]
Threshold
F
TH
ksi [MPa]
Slope
m
Potential
crack
initiation
Illustrative
Example
Hilti S-BT screw-in stainless and
carbon steel threaded studs with pre-
drilled hole in structural steel base
material.
Imperfect fastener installations as e.g.
overwound or pulled-out fasteners are
covered.
 to be calculated by the gross
cross-section.
Installation, static loading and spacing
of fasteners only in accordance with
the requirements given in [1] or [2].
Plate thickness t  3 mm.
Steel base material up to yield
strength 355 MPa.
S-BT
6065x10
10
[1.995x10
16
]
12.6
[87.0]
5.0
At the edge
or tip of the
pre-drilled
hole
[1] Hilti S-BT screw-in threaded studs. Specification Binder, Edition 01/2017
[2] Hilti Direct Fastening Technology Manual. Edition 12/2016. S-BT product pages.
10.2.4 ABS:2014
It is recommended to use the following S-N curve respectively stress category termed “S-BT”
given in
Table 10.3 for the constructional detail “Steel base material with Hilti S-BT screw-in
threaded studs”.
Table 10.3. Recommendation of fatigue S-N curve and fatigue class according to ABS-(A):2014
Description and notes on mode
of failure
Class Explanatory comments
Example including
failure modes
Hilti S-BT screw-in stainless and carbon
steel threaded studs with pre-drilled hole
in structural steel base material.
Imperfect fastener installations as e.g.
overwound or pulled-out fasteners are
covered.
Potential crack initiation at the edge or
tip of the pre-drilled hole.
S-BT
 to be calculated by the gross
cross-section.
Installation, static loading and
spacing of fasteners only in ac-
cordance with the requirements
given in [1] or [2].
Plate thickness t  3 mm.
Steel base material up to yield
strength 355 MPa.
Parameter of design S-N curve class S-BT
Curve A m r N
Q
S
Q
Class for [MPa]
units
for [ksi]
units
for [MPa]
units
for [ksi]
units
for [MPa]
units
for [ksi]
units
S-BT 1.995x10
16
1.28x10
12
5.0 1.995x10
16
1.28x10
12
5.0 1.0x10
7
72.4 10.50
[1] Hilti S-BT screw-in threaded studs. Specification Binder, Edition 01/2017
[2] Hilti Direct Fastening Technology Manual. Edition 12/2016. S-BT product pages.
ABS:2014
ItisrecommendedtousethefollowingdesignS-Ncurverespectivelystress
categorytermed“S-BT”giveninTable5andFigure3fortheconstructional
detail“SteelbasematerialwithHiltiS-BTscrew-inthreadedstuds”.
Universität Stuttgart
Institut für Konstruktion und Entwurf
Schwerpunkte: Stahlbau, Holzbau und Verbundbau
Prof. Dr.-Ing. Ulrike Kuhlmann
2017-06-30 S-BT Fatigue Page 36
9.2.3 Recommendation of a design S-N curve for ABS
ABS:2003 includes following 8 S-N curves for non-tubular details in air, see Table 9.3. The
slope intersection is at 1
∙10
7
number of cycles. In general the slope is m = 3 for curve D to W as
typical for welded details. However, for mild details (curve B and C) the slope is more shallow
with m = 3.5 to 4.
Based on the statistical evaluation of the Hilti S-BT fatigue test data according to
Table 9.1 an
additional class “S-BT” is proposed having a uniform slope of m = 5, see following
Table 9.3
and
Figure 32. According to the standard S-N curves given in ABS the slope is set to be con-
stant to m = 5 beyond N
Q
= 1∙10
7
.
Table 9.3. ABS-(A) S-N curves and new proposed S-N curve for Hilti S-BT fastener
Curve A m r N
Q
S
Q
Class for [MPa]
units
for [ksi]
units
for [MPa]
units
for [ksi]
units
for [MPa]
units
for [ksi]
units
B
1.01
x10
15
4.48x10
11
4.0 1.02x10
19
9.49x10
13
6.0 1.0x10
7
100.2 14.5
C
4.23
x10
13
4.93x10
10
3.5 2.59x10
17
6.35x10
12
5.5 1.0x10
7
78.2 11.4
D
1.52
x10
12
4.65x10
9
3.0 4.33x10
15
2.79x10
11
5.0 1.0x10
7
53.4 7.75
E
1.04
x10
12
3.18x10
9
3.0 2.30x10
15
1.48x10
11
5.0 1.0x10
7
47.0 6.83
F
6.30
x10
11
1.93x10
9
3.0 9.97x10
14
6.24x10
10
5.0 1.0x10
7
39.8 5.78
F2
4.30
x10
11
1.31x10
9
3.0 5.28x10
14
3.40x10
10
5.0 1.0x10
7
35.0 5.08
G
2.50
x10
11
7.64x10
8
3.0 2.14x10
14
1.38x10
10
5.0 1.0x10
7
29.2 4.24
W
1.60
x10
11
4.89x10
8
3.0 1.02x10
14
6.54x10
9
5.0 1.0x10
7
25.2 3.66
S-BT 1.995x10
16
1.28x10
12
5.0 1.995x10
16
1.28x10
12
5.0 1.0x10
7
72.4 10.50
10
100
10.000 100.000 1.000.000 10.000.000
Number of cycles N [-]
Nominal stress range  [N/mm
2
]
300
200
100
400
50
500
B
10
70
20



t
Hilti S-BT
C
D
F
E
A
BS
classes
welded stud
F2
G
W
Hilti S-BT fastener
(correct installed condition)
Hilti S-BT fastener
(installed and removed)
proposed design S-N curve
m =5
1
Figure 32. Comparison of Hilti S-BT fatigue test data with ABS-(A) Offshore S-N curves
and new proposed fatigue class “S-BT” for Hilti S-BT fastener
Figure3:ComparisonofHiltiS-BTfatiguetestdatawithABS-(A)OffshoreS-N
curvesandnewproposedfatigueclass“S-BT”forHiltiS-BTfastener
Table5:RecommendationoffatigueS-Ncurveandfatigueclassacc.to
ABS-(A):2014