NS - Notched Stud Backing

Notched Stud Backing (NS) is used for bracing and bridging of joists and wall studs in heavy load conditions. NS is also used in hospitals and schools as mechanical backing to provide superior support for equipment and cabinetry. Engineered section properties and allowable loads are provided based on 2004 AISI.

Features & Benefits

  • Pre-cut notches for flange attachment
  • Pre-drilled guide holes
  • Eliminates field cutting
  • Provides bracing and bridging support

Material Composition

  • ASTM A653 / A653M

Yield Strength

  • 30, 33, and 43 mil: 33 ksi 
  • 54, 68 mil: 57 ksi

Coating Thickness

  • 30 mil: G40 hot-dipped galvanized coating
  • 33, 43, 54 mil: G60 hot-dipped galvanized coating
  • 68 mil: G90 hot-dipped galvanized coating

Material Thickness

  • 30 mil
  • 33 mil
  • 43 mil
  • 54 mil 
  • 68 mil

Nomenclature


Section Properties

1/2" Flange NS Section Properties - Per AISI Design Criteria
Backing
Member
Thickness
(mils)
Thickness
(ga)
Depth
(in)
Flange
(in)
Fy
(ksi)
Ixe (min)(In4) Sxe (min)(In3) Iye (min)(In4) Sye (min)(In3)
4", 33 mil 33 20 4 0.50 33 0.386 0.193 0.007 0.018
4", 43 mil 43 18 4 0.50 33 0.495 0.248 0.008 0.022
4", 54 mil 54 16 4 0.50 50 0.603 0.301 0.009 0.025
4", 68 mil 68 14 4 0.50 50 0.728 0.364 0.011 0.029
6", 33 mil 33 20 6 0.50 33 1.085 0.357 0.007 0.018
6", 43 mil 43 18 6 0.50 33 1.416 0.472 0.009 0.022
6", 54 mil 54 16 6 0.50 50 1.736 0.579 0.010 0.026
6", 68 mil 68 14 6 0.50 50 2.116 0.705 0.012 0.030
8", 33 mil 33 20 8 0.50 33 2.214 0.526 0.007 0.018
8", 43 mil 43 18 8 0.50 33 2.989 0.738 0.009 0.022
8", 54 mil 54 16 8 0.50 50 3.727 0.932 0.011 0.026
8", 68 mil 68 14 8 0.50 50 4.569 1.142 0.012 0.030

 

1" Flange NS Section Properties - Per AISI Design Criteria
Backing
Member
Thickness
(mils)
Thickness
(ga)
Depth
(in)
Flange
(in)
Fy
(ksi)
Ixe (min)(in4) Sxe (min)(in3) Iye (min)(in4) Sye (min)(in3)
4", 33 mil 33 20 4 1.00 33 0.522 0.261 0.033 0.046
4", 43 mil 43 18 4 1.00 33 0.672 0.336 0.041 0.058
4", 54 mil 54 16 4 1.00 50 0.823 0.411 0.050 0.070
4", 68 mil 68 14 4 1.00 50 1.003 0.501 0.059 0.082
6", 33 mil 33 20 6 1.00 33 1.371 0.445 0.036 0.047
6", 43 mil 43 18 6 1.00 33 1.816 0.605 0.046 0.060
6", 54 mil 54 16 6 1.00 50 2.236 0.745 0.056 0.072
6", 68 mil 68 14 6 1.00 50 2.742 0.914 0.066 0.085
8", 33 mil 33 20 8 1.00 33 2.687 0.626 0.037 0.047
8", 43 mil 43 18 8 1.00 33 3.610 0.872 0.048 0.060
8", 54 mil 54 16 8 1.00 50 4.492 1.092 0.058 0.072
8", 68 mil 68 14 8 1.00 50 5.690 1.423 0.070 0.086

 

 

Allowable Loads

1/2" Flange Allowable Load Capacities
Backing
Member
Mx
(lb*ft)
Vy
(lb)
Pmax2
(lb)
#10 Screw3
(lb)
# Of Screw4
Req’d for Pmax
4", 33  mil 257 976 308 177 2
4", 43 mil 379 1739 455 263 2
4", 54 mil 495 3372 594 500 2
4", 68 mil 593 4871 712 500 2
6", 33 mil 406 638 487 177 3
6", 43 mil 557 1415 668 263 3
6", 54 mil 767 2822 920 500 2
6", 68 mil 901 5350 1081 500 3
8", 33 mil 540 474 474 177 3
8", 43 mil 752 1051 902 263 4
8", 54 mil 1008 2091 1210 500 3
8", 68 mil 1228 4220 1474 500 3

1" Flange Allowable Load Capacities
Backing
Member
Mx
(lb*ft)
Vy
(lb)
Pmax2
(lb)
#10 Screw3
(lb)
# Of Screw4
Req'd for Pmax
4", 33 mil 486 976 583 177 4
4", 43 mil 641 1739 769 263 3
4", 54 mil 1146 3372 1375 500 3
4", 68 mil 1432 4871 1718 500 4
6", 33 mil 683 638 638 177 4
6", 43 mil 939 1415 1127 263 5
6", 54 mil 1705 2822 2046 500 5
6", 68 mil 2183 5350 2620 500 6
8", 33 mil 944 474 474 177 3
8", 43 mil 1318 1051 1051 263 4
8", 54 mil 2375 2091 2091 500 5
8", 68 mil 3118 4220 3742 500 8

Table Notes:        

  1. The 8-inch, 20 ga member has a w/t ratio that exceeds 200. Web stiffeners are required at all concentrated loads.
  2. Maximum point load (Pmax) is determined based on the minimum of the shear capacity of the member, the bending capacity of the member, or the number of screws used to install the member (provided they have the proper edge distance and spacing). Load assumed to act at mid-span through centroid of backing member, based on a span of 24”. For stud spacing of 16” O.C., above tables may conservatively be used.
  3. Screw capacity based on stud material with thickness and yields strength equal to the blocking/backing member. Minimum screw spacing and edge distance shall not be less than three time the nominal screw diameter (per SSMA). For #10 screw, 3 x d = 3 x 0. 190” = 0.57”.
  4. Number of screws determined by dividing Pmax by capacity of #10 screw and rounding up. Screw manufacturer shall confirm that their screws meet the code allowable capacity indicated in the table.
  5. Gauge thickness to be per SSMA: 33 mil = 0.0346”, 43 mil = 0.0451”, 54 mil = 0.0566”, 68 mil = 0.0713”.
  6. Inside corner radius at bends to be per SSMA: 33 mil: R = 0.0764", 43 mil: R = 0.0712", 54 mil: R = 0.0849", 68 mil: R = 0.1069".
  7. Member analysis assumes that the materials and protective coatings for the cold-formed steel used to manufacture the blocking/backing members matches the relevant ASTM requirements used for the production of SSMA members.
  8. The properties indicated in the table have been calculated using CFS version 5.0.2 (RSG Software Inc.)
  9. Tabulated values do not consider stud capacity. Studs designed by others.
  10. All calculations based on 2004 AISI.