Direct Fastening Technical Guide , Edition 24
Example problem Design parameters :
Load type : Wind Design method : ASD Span , L v
: 6 ' -0 " No . of Spans : 3 Total Length , L : 18 ' -0 " Deck : No . 20 gage ( 0.0358 inch ) 1-1 / 2 " deep B-Deck ( F y
= 50 ksi ) Support Framing : Steel Bar Joist with 1 / 4 " Thick Top Chord Frame Fastener : X-HSN 24 Frame Fastener Pattern : 36 / 7 Sidelap Fastener : Hilti SLC Sidelap fastener spacing ( SS ): 12 " o . c .
Design problem :
Determine Allowable ( ASD ) Diaphragm Shear Strength S n
Ω and Stiffness ( G ') for the given steel deck diaphragm .
X-HSN 24
Hilti SLC
6 "
36 " 1-1 / 2 "
Step 1 : Calculate nominal diaphragm shear strength limited by panel fasteners :
S ni
= { 2 x A x ( λ- 1 ) + ß } x P nf
= { 2 x 1 x ( 0.802 - 1 ) + 16.99 } x 2 , 107 = 1,942 plf L 18
AISI S310 Eq . D1-1
Where : A = 1
λ = 1- |
D d x L v |
= 1- |
1.5 x 6 |
|
240 x t |
|
240 x 0.0358 |
ß = n s x α s
+ 2n p α p
2
+ 4α e
2
= 0.802 ≥ 0.7
Technical Guide Table 7
AISI S310 Eq . D1-4a
AISI S310 Eq . D1-5 α p
2
= ( 1 ) Σ x p
2 w 2 AISI S310 Eq . D1-7 α e
2
= ( 1 ) Σ x e
2 w 2 AISI S310 Eq . D1-8 n p
= 2
ß = n s x α s
+ 2n p α p
2
+ 4α e
2
= 1 x [ 2 x 2.0 x S ( x p
2
) + 4 S ( x e
2
) ] = w 2
18 x 0.598 + [ 2 x 2 x 1 , 008 + 4 x 1 , 008 ] = 16.99
36 2
Σ ( x p
2
) = Σ ( x e
2
) ] = 1,008 Technical Guide Table 7 α s
= P ns = 1 , 260 = 0.598
P nf
2,107 AISI S310 Eq . D1-5 Step 2 : Calculate nominal diaphragm shear strength limited by corner fasteners :
S nc
= P nf x
N 2 x ß 2
2.00 = 2,107 x 2 x 16.99 2 = 1,798 plf
AISI S310 Eq . D1-2
L 2 x N 2 + ß 2 18 2 x 2.00 2 + 16.99 2
Where : N = 2.00 ß = same as in step 1
Technical Guide Table 7
169