Steel Deck Fastening Systems
1.1 Steel Deck Fastener Design and Selection Example problem
Design parameters :
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
Design problem :
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 .
Hilti SLC
6 " 36 " 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 :
S ni
= { 2 x A x ( λ- 1 ) + B } x Q f
= { 2 x 1 x ( 0.802 - 1 ) + 16.99 } x 2107 = 1,942 plf
< 18 with : λ = 1- 1 . 5 x < 1.5 x 6
v
= 1- = 0.802 ≥ 0.7
240 x t 240 x 0.0358 1
2 2
B = n s x α s
+ x [ 2 x 2 x S ( x p ) + 4 S ( x e
) ] = 18 x 0.598 + [ 2 x 2 x 1008 + 4 x 1008 ] = 16.99 w 2 36 2 where : 3 x < n s
= n e
= v x 12
= 3 x 6 x 12 = 18 Sidelap Spacing 12 α s
= Q s
= 1260 = 0.598
Q f
2107 Step 3 : Calculate nominal diaphragm shear strength limited by corner fasteners :
S nc
= Q f x
N 2 x B 2
2.00 = 2107 x 2 x 16.99 2 = 1,798 plf
< 2 x N 2 + B 2 18 2 x 2.00 2 + 16.99 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
SDI DDM03 Ref .
Eq . 2.2-2
Eq . 2.2.3
Eq . 2.2-5
Sec . 2.4
HNA Technical Guide
Sec . 1.1.8
Sec . 1.1.8 and Tables 7 and 8
Sec . 1.1.8 and Tables 7 and 8
Sec . 1.1.8 and Table 8
Table 11
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
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