6″ Box Rib

6″ Rib is currently the most popular and widely used panel for decking. Type 6″ Rib is frequently used for several applications such as flooring, siding, and roofing.

Notes

  1. An asterisk (*) indicates allowable stress has been reached.
  2. A strikethrough (100) indicates less than 10 small PSF ASCE minimum.
  3. For structural roofing & siding made of formed metal sheets, a total load deflection shall not exceed L/60.
  4. Refer to Table 1604.3 limits and footnotes of the International Building Code (IBC) for additional guidance.
  5. Allowable spans and loads DO include self-weight of panel.
  6. All values are for one foot of panel width unless noted otherwise.
  1. Yield stress = Fy = 33,000 psi.
  2. Loads and spans for carbon steel are based on AISI Standard for Design of Cold-Formed Steel Structure Members (2007 Edition).
  1. Yield stress = Fcy = 13,000 PSI.
  2. Loads and spans for aluminum are based on Aluminum Design Manual (January 2005).

Resources

PRODUCT CHARACTERISTICS

Load Table

Section Weight Total Cross-Sectional
Area A (in2)		 Allowable Stress
Fa (psi)		 Top Flat in Compression Bottom Flat in Compression
Sheet
lb/ft		 Area
lb/sf		 Moment of Inertia
I (in4/ft)		 Section Modulus
S (in3/ft)		 Allowable Momen
Ma (lb-ft/ft)		 Moment of Inertia
I (in4/ft)		 Section Modulus
S (in3/ft)		 Allowable Moment
Ma (lb-ft/ft)
18 Ga 8.24 2.70 2.42 19760 0.291 0.322 530 0.261 0.395 650
20 Ga 6.60 2.16 1.94 19760 0.233 0.258 425 0.196 0.285 469
22 Ga 5.12 1.68 1.50 19760 0.180 0.200 330 0.141 0.196 322
24 Ga 4.46 1.46 1.31 19760 0.153 0.169 278 0.119 0.160 264
0.05 Alum 2.87 0.94 2.42 5304 0.291 0.322 230 0.291 0.489 231
0.04 Alum 2.29 0.75 1.94 4434 0.233 0.258 168 0.233 0.394 153
0.032 Alum 1.84 0.60 1.55 3821 0.186 0.208 125 0.186 0.319 107

Table 1: Applied Load (PSF)

An asterisk (*) indicates allowable stress has been reached.

Table 1 Applied Load (PSF)
Allowable Spans 10 20 30 40 50 60
Section Span Limit Span Type Allowable Spans (ft)
18 Ga L/60 1 Span 17′-5″ 13′-8″ * 11′-5″ * 10′-0″ * 9-0″ * 8′-3″ *
2 Span 20′-3″ * 15′-2″ * 12′-7″ * 11′-0″ * 9′-11″ * 9′-1″ *
3 Span 19′-10″ 15′-2″ * 12′-8″ * 11′-1″ * 10′-0″ * 9′-2″ *
L/240 1 Span 11′-0″ 9′-1″ 8′-0″ 7′-4″ 6′-10″ 6′-5″
2 Span 12′-9″ 10′-6″ 9′-4″ 8′-6″ 7′-11″ 7′-6″
3 Span 12′-6″ 10′-3″ 9′-1″ 8′-4″ 7′-9″ 7′-4″
20 Ga L/60 1 Span 16′-1″ 12′-5″ * 10′-3″ * 9′-0″ * 8′-1″ * 7′-5″ *
2 Span 17′-7″ * 13′-0″ * 10′-10″ * 9′-5″ * 8′-6″ * 7′-9″ *
3 Span 18′-2″ * 13′-5″ * 11′-2″ * 9′-9″ * 8′-9″ * 8′-0″ *
L/240 1 Span 10′-2″ 8′-4″ 7′-4″ 6′-8″ 6′-3″ 5′-11″
2 Span 12′-0″ 9′-10″ 8′-8″ 7′-11″ 7′-5″ 7′-0″
3 Span 11′-9″ 9′-7″ 8′-6″ 7′-9″ 7′-3″ 6′-10″
22 Ga L/60 1 Span 14′-7″ 10′-11″ * 9′-0″ * 7′-10″ * 7′-1″ * 6′-6″ *
2 Span 14′-10″ * 10′-11″ * 9′-0″ * 7′-10″ * 7′-1″ * 6′-6″ *
3 Span 15′-4″ * 11′-3″ * 9′-4″ * 8′-2″ * 7′-4″ * 6′-8″ *
L/240 1 Span 9′-2″ 7′-6″ 6′-7″ 6′-0″ 5′-7″ 5′-3″
2 Span 11′-2″ 9′-1″ 8′-0″ 7′-4″ 6′-10″ 6′-5″
3 Span 10′-11″ 8′-11″ 7′-10″ 7′-2″ 6′-8″ 6′-3″
24 Ga L/60 1 Span 13′-7″ * 9-11″ * 8′-2″ * 7′-2″ * 6′-5″ * 5′-10″ *
2 Span 13′-7″ * 9-11″ * 8′-2″ * 7′-2″ * 6′-5″ * 5′-10″ *
3 Span 14′-0″ * 10′-5″ * 8′-6″ * 7′-4″ * 6′-7″ * 6′-1″ *
L/240 1 Span 8′-9″ 7′-1″ 6′-3″ 5′-8″ 5′-4″ 5′-0″
2 Span 10′-8″ 8′-8″ 7′-8″ 6′-11″ 6′-5″ * 5′-10″ *
3 Span 10′-5″ 8′-5″ 7′-5″ 6′-9″ 6′-4″ 5′-11″
0.32 Alum L/60 1 Span 8′-9″ * 6′-3″ * 5′-2″ * 4′-6″ * 4′-0″ * 3′-8″ *
2 Span 8′-9″ * 6′-3″ * 5′-2″ * 4′-6″ * 4′-0″ * 3′-8″ *
3 Span 9′-1″ * 6′-6″ * 5′-4″ * 4′-7″ * 4′-2″ * 3′-9″ *
L/240 1 Span 7′-4″ 5′-11″ 5′-2″ 4′-6″ * 4′-0″ * 3′-8″ *
2 Span 8′-3″ 6′-3″ * 5′-2″ * 4′-6″ * 4′-0″ * 3′-8″ *
3 Span 8′-0″ 6′-5″ 5′-4″ * 4′-7″ * 4′-2″ * 3′-9″ *
0.04 Alum L/60 1 Span 10′-5″ * 7′-6″ * 6′-2″ * 5′-4″ * 4′-9″ * 4′-5″ *
2 Span 10′-5″ * 7′-6″ * 6′-2″ * 5′-4″ * 4′-9″ * 4′-5″ *
3 Span 10′-9″ * 7′-9″ * 6′-4″ * 5′-6″ * 4′-11″ * 4′-6″ *
L/240 1 Span 7′-10″ 6′-4″ 5′-6″ 5′-0″ 4′-8″ 4′-5″ *
2 Span 8′-10″ 7′-1″ 6′-2″ * 5′-4″ * 4′-9″ * 4′-5″ *
3 Span 8′-7″ 6′-11″ 6′-1″ 5′-6″ 4′-11″ * 4′-6″ *
0.05 Alum L/60 1 Span 12′-7″ * 9′-1″ * 7′-6″ * 6′-6″ * 5′-10″ * 5′-4″ *
2 Span 12′-7″ * 9′-1″ * 7′-6″ * 6′-6″ * 5′-10″ * 5′-4″ *
3 Span 13′-0″ * 9′-5″ * 7′-9″ * 6′-9″ * 6′-0″ * 5′-6″ *
L/240 1 Span 8′-5″ 6′-9″ 5′-11″ 5′-5″ 5′-1″ 4′-9″
2 Span 9′-5″ 7′-7″ 6′-8″ 6′-1″ 5′-8″ 5′-4″ *
3 Span 9′-3″ 7′-5″ 6′-6″ 5′-11″ 5′-6″ 5′-2″

TABLE 2: TRIAL SPAN (FT)

An asterisk (*) indicates allowable stress has been reached. A strikethrough (100) indicates less than 10 small PSF ASCE minimum.

Table 2 Trial Span (ft)
Allowable Loads 3 4 5 6 7 8 9 10 11 12
Section Span Limit Span Type Allowable Loads (PSF)
18 Ga L/60 1 Span 368 * 262 * 166 * 115 * 83 * 63 * 49 * 39 * 32 * 26 *
2 Span 575 * 322 * 205 * 141 * 103 * 78 * 61 * 49 * 40 * 33 *
3 Span 579 * 325 * 207 * 142 * 104 * 79 * 62 * 49 * 40 * 33 *
L/240 1 Span 468 * 260 131 75 46 30 20 14 9 7
2 Span 575 * 322 * 205 * 120 74 49 33 23 17 12
3 Span 579 * 325 * 194 111 69 45 31 21 15 11
20 Ga L/60 1 Span 375 * 210 * 133 * 92 * 67 * 51 * 39 * 31 * 25 * 21 *
2 Span 415 * 232 * 148 * 102 * 74 * 56 * 44 * 35 * 28 * 23 *
3 Span 443 * 248 * 158 * 109 * 79 * 60 * 47 * 37 * 30 * 25 *
L/240 1 Span 375 * 195 99 56 34 22 15 10 7 5
2 Span 415 * 232 * 148 * 96 59 39 26 19 13 10
3 Span 443 * 248 * 155 89 55 36 24 17 12 9
22 Ga L/60 1 Span 284 * 159 * 101 * 69 * 50 * 38 * 30 * 24 * 19 * 16 *
2 Span 284 * 159 * 101 * 69 * 50 * 38 * 30 * 24 * 19 * 16 *
3 Span 304 * 170 * 108 * 74 * 54 * 41 * 32 * 25 * 21 * 17 *
L/240 1 Span 284 * 140 71 40 24 16 10 7 5 3
2 Span 284 * 159 * 101 * 69 * 46 30 20 14 10 7
3 Span 304 * 170 * 108 * 68 42 28 19 13 9 7
24 Ga L/60 1 Span 232 * 130 * 82 * 57 * 41 * 31 * 24 * 19 * 15 * 13 *
2 Span 232 * 130 * 82 * 57 * 41 * 31 * 24 * 19 * 15 * 13 *
3 Span 248 * 139 * 88 * 61 * 44 * 33 * 26 * 21 * 17 * 14 *
L/240 1 Span 232 * 117 59 33 20 13 9 6 4 2
2 Span 232 * 130 * 82 * 57 * 39 25 17 12 9 6
3 Span 248 * 139 * 88 * 58 36 23 16 11 8 6
0.32 Alum L/60 1 Span 89 * 50 * 31 * 21 * 15 * 12 * 9 * 7 * 6 * 5 *
2 Span 89 * 50 * 31 * 21 * 15 * 12 * 9 * 7 * 6 * 5 *
3 Span 95 * 53 * 34 * 23 * 17 * 12 * 10 * 8 * 6 * 5 *
L/240 1 Span 89 * 50 * 31 * 18 11 7 5 3 2 1
2 Span 89 * 50 * 31 * 21 * 15 * 10 7 5 3 2
3 Span 95 * 53 * 34 * 23 * 15 10 6 4 3 2
0.04 Alum L/60 1 Span 128 * 72 * 45 * 31 * 23 * 17 * 13 * 10 * 8 * 7 *
2 Span 128 * 72 * 45 * 31 * 23 * 17 * 13 * 10 * 8 * 7 *
3 Span 137 * 76 * 48 * 33 * 24 * 18 * 14 * 11 * 9 * 7 *
L/240 1 Span 128 * 72 * 40 23 14 9 6 4 3 2
2 Span 128 * 72 * 45 * 31 * 20 13 9 6 4 2
3 Span 137 * 76 * 48 * 31 19 12 8 6 4 3
0.05 Alum L/60 1 Span 191 * 107 * 68 * 47 * 34 * 26 * 20 * 16 * 13 * 11 *
2 Span 191 * 107 * 68 * 47 * 34 * 26 * 20 * 16 * 13 * 11 *
3 Span 204 * 114 * 72 * 50 * 36 * 27 * 21 * 17 * 14 * 11 *
L/240 1 Span 191 * 101 51 29 18 11 8 5 3 2
2 Span 191 * 107 * 68 * 41 26 17 11 8 6 4
3 Span 204 * 114 * 67 38 24 15 10 7 5 4

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