MEP-Technical Manual CDN 0408.qxd - Hambro

DESIGN PRINCIPLES AND CALCULATIONS
TABLE 9: Slab Capacity Chart (Total Unfactored Load in psf) *
SLAB d MESH SIZE (6” x 6”) 4’-1 1 /4” JOIST SPACING 5’-1 1 /4” JOIST SPACING
THICKNESS (t) (in.) f’ c = 3 000 psi, � = 145 lb./sq. ft. Exterior Interior Exterior Interior
F y = 60 000 psi (1) (1) (1) (1)
2 3/ 4” ≤ t < 3 1/ 2”
NO CHAIR
3 1/ 2” ≤ t ≤ 4 1/ 2”
NO CHAIR
4 1/ 2” ≤ t ≤ 5 1/ 2”
WITH 3” CHAIR
INTERIOR AND
EXTERIOR EXPOSURE (1)
2 layers 10/10 157 172 103 112
1.6 1 layer 6/6 159 176 105 115
1.6
1 layer 4/4 212 239 141 155
1 layer 4/4 219 240 143 156
2 layers 8/8 221 242 144 157
2 layers 6/6 301 328 195 213
2 layers 4/4 399 430 256 280
2 layers 6/6 301 331 175 191
3.1 2 layers 4/4 408 450 264 291
* Loads indicated are the total allowable service load (W s ) that the slab
can carry. W s is determined from the conservative equation:
W s = (W f - 1.25D) / 1.5 + D
Where W f = factored total load
D = minimum dead load (weight of slab + joist)
(1) Wire mesh : 1 layer on top chord and 1 layer on high chair
Note: Slab capacities are based on mesh over joist raised as indicated.
2 layers 2/2 542 596 349 383
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