TM 5-809-12/AFM 88-3, Chap. 15
3-4. Wall loads.
3-5. Unusual loads.
Floor slabs on grade should have adequate thickness
Information regarding floor slab requirements for
to carry wall loads. Tables 3-2 and 3-3 show the
special purpose ordnance, engineer, or transport
minimum thicknesses of thickened slabs for various
vehicles producing loads significantly greater than
wall loads. The equations used to compute these
those defined herein should be requested from
values are included in appendix B. When slab
Headquarters, Department of the Army (HQDA)
thickness required for wall loads exceeds that
(DAEN-ECE-G) Washington, DC 20314-1000 or
required for moving live loads or stationary live
Headquarters, Air Force Engineering and Services
loads, the slab will be thickened in accordance with
Center (DEMP), Tyndall MB, Fla. 32403.
figure 3-1. The safety factor for the design was
considered by using a reduced allowable tensile
stress of the concrete, ot , which was computed
using the equation ot = 1.6 /f'c, where f'c is the
ultimate compressive strength of the concrete. If
wall loads exceed the tabulated values shown in
table 3-2, separate wall footings are suggested.
Figure 3-la shows the widths of thickened slabs
when the interior wall loads are near the slab center.
A recommended transition is also shown. The
thickened slab width is determined by the same
theory as the wall loads. The slab under the wall is
widened to the point where the stress in the thinner
slab section does not exceed the allowable tensile
stress of 1.6 /f'c. Figure 3-1b shows a slab loaded
near a keyed or doweled edge. Figure 3-lc shows a
recommended slab thickening for a slab loaded near
a free edge. The width of the thickened edge varies
depending upon the width of the wall.
3-4
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