TM 5-809-12/AFM 88-3, Chap. 15
3-3. Stationary live loads.
k = the modulus of subgrade reaction, pounds
per cubic inch
Floor slabs on grade should have adequate
h = the slab thickness, inches
structural live loads. Since floor slabs are designed
E= the modulus of elasticity for the slab
for moving live loads, the design should be checked
(assumed to equal 4.0 x 106 pounds per
for stationary live loading conditions. Table 3-1 lists
square inch)
values for maximum stationary live loads on floor
slabs. For very heavy stationary live loads, the floor
The above equation may be used to find allowable
slab thicknesses listed in table 3-1 will control the
loads for combinations of values of s, h, and knot
design. Table 3-1 was prepared using the equation
given in table 3-1. Further safety may be obtained by
reducing allowable extreme fiber stress to a smaller
percentage of the concrete flexural strength have
kh
w ' 257.876s
(eq 3-1)
been presented by Grieb and Werner, Waddell, and
E
Hammitt (see Biblio). The selection of the modulus
of subgrade reaction for use in table 3-1 is discussed
in paragraph 4-2d. The design should be examined
where
for the possibility of differential settlements which
w = the maximum allowable distributed
could result from nonuniform subgrade support.
stationary live load, pounds per square foot
Also, consideration of the effects of long-term
s = the allowable extreme fiber stress in tension
overall settlement for stationary live loads may be
excluding shrinkage stress and is assumed to
necessary for compressible soils (see TM 5-818-
be equal to one-half the normal 28-day
1/AFM 88-3, Chap. 7).
concrete flexural strength, pounds per
square inch
3-2
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