Steel Deck Fastening Systems
1.1 Steel Deck Fastener Design and Selection
Example problem
Design parameters: Design problem:
Load type: Wind
Design method: ASD
Span: 6'-0"
Deck: 20 GA. 1-1/2" B-Deck (f u ≥ 45 ksi)
Base steel: Bar joist with 1/4" top chord
Frame fastener pattern: 36/7
Sidelap fastener spacing: 12" O.C.
Frame fastener: X-HSN 24
Sidelap fastener: Hilti SLC
Required diaphragm shear (Q): 650 plf
Required uplift (T): 35 psf Determine allowable diaphragm
shear strength (S ASD ), uplift
(T n (ASD) ) and stiffness (G') for the
given steel deck diaphragm
and check against
required loads.
6"
36"
Hilti
SLC
1-1/2"
X-HSN 24
Calculation steps
Step 1: Calculate nominal diaphragm shear strength limited by edge fasteners:
This calculation is not required when the number of edge connectors (n e ) equals the number of sidelap
fasteners (n s ). In these cases, S ne does not limit diaphragm shear strength.
Step 2: Calculate nominal diaphragm shear strength limited by interior panel fasteners:
Q
2107
S ni = {2 x A x (λ- 1) + B} x f = {2 x 1 x (0.802 - 1) + 16.99} x
= 1,942 plf
<
18
with:
1.5 x < v
1.5 x 6
λ = 1-
= 1-
= 0.802 ≥ 0.7
240 x t
240 x 0.0358
1
[2 x 2 x 1008 + 4 x 1008]
B = n s x α s +
x [ 2 x 2 x S ( x p2 ) + 4 S ( x e2 ) ] = 18 x 0.598 +
= 16.99
2
w
36 2
where:
3 x < v x 12
3 x 6 x 12
n s = n e =
=
= 18
Sidelap Spacing
12
α s =
SDI
DDM03
Ref. HNA
Technical
Guide
Eq.
2.2-2 Sec.
1.1.8
Eq.
2.2.3 Sec.
1.1.8
and
Tables
7 and 8
Eq.
2.2-5 Sec.
1.1.8
and
Tables
7 and 8
Q s
1260
=
= 0.598
2107
Q f
Step 3: Calculate nominal diaphragm shear strength limited by corner fasteners:
S nc = Q f x
N x B
= 2107 x
< 2 x N 2 + B 2
2
2
2.00 x 16.99
= 1,798 plf
18 2 x 2.00 2 + 16.99 2
2
2
Step 4: Apply correlation factor, c, to determine correlated nominal diaphragm shear strength
S = c x S n = 1.102 x 1,798 = 1,981 plf
where:
S n = least of S ne , S ni and S nc = S nc = 1,798 plf
Step 5: Apply appropriate conversion factor to determine allowable diaphragm strength
S ASD (wind) = S x Conversion Factor = 1,981 x 0.426 = 844 plf
Step 6: Check to see if steel deck buckling controls
S buckling (ASD) = 2,750 plf > S ASD (wind) therefore, S ASD (wind) = 844 plf ≥ 650 plf
Sec.
1.1.8
and
Table 8
Sec.
2.4
Table 11
Table 12
22 Hilti, Inc. (US) 1-800-879-8000 | www.us.hilti.com I en español 1-800-879-5000 I Hilti (Canada) Corp. 1-800-363-4458 I www.hilti.ca I PTG Decking Supplement 2014