TM 5-809-12/AFM 88-3, Chap. 15
b. Thickness design on stabilized base or sub-
may be either deformed bars or welded wire fabric.
grade. To determine the thickness requirements for
Specifications for both types of reinforcement are
reinforced concrete floor slabs on a stabilized
given in TM 5-825-3/AFM 88-6, Chap. 3.
(2) Placement. Placement of the reinforcing
foundation, it is first necessary to determine the
thickness of nonreinforced concrete floor slab
steel in floor slabs should follow the criteria given in
required for the design conditions. This thickness of
TM 5-825-3/AFM 88-6, Chap. 3. In addition, the
nonreinforced floor slab is determined by the
following criteria regarding the maximum spacing of
procedures set forth in paragraph 5-2d. Figure 5-4
reinforcement should be observed. For welded wire
is then entered with the values of h , hr, and S
fabric, the maximum spacing of the longitudinal
c. Limitations. The design criteria for reinforced
wires and transverse wires should not exceed 6
concrete floor slabs on grade are subject to the
inches and 12 inches, respectively; for bar mats, the
following limitations:
maximum spacing of the longitudinal bars and the
(1) No reduction in the required thickness of
transverse bars should not exceed 15 inches and 30
nonreinforced floor slabs should be allowed for per-
inches, respectively.
centages of steel less than 0.05 percent.
5-7. Joint types and usage.
(2) No further reduction in the required
thickness of nonreinforced floor slabs should be
Joints are provided to permit contraction and expan-
allowed over that indicated in figure 5-4 for 0.50
sion of the concrete resulting from temperature and
percent steel, regardless of the percentage of steel
moisture changes, to relieve warping and curling
used.
stresses due to temperature and moisture differen-
(3) The maximum length L of reinforced
tials, to prevent unsightly, irregular breaking of the
floor slabs should not exceed 75 feet regardless of
floor slab; as a construction expedient, to separate
the percentage of steel, yield strength of the steel, or
sections or strips of concrete placed at different
thickness of the pavement.
times; and to isolate the floor slab from other
(4) The minimum thickness of reinforced
building components. The three general types of
floor slabs should be 6 inches.
joints are contraction, construction, and isolation. A
d. Reinforcing steel.
typical floor-slab joint layout is shown in figure 5-5.
(1) Type. The reinforcing steel for floor slabs
5-10
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