30 June 2001
hd = design thickness of reinforced concrete, millimeters (inches)
ys = yield strength of reinforcing steel, normally 413.7 MPa (60,000 psi)
S = percent reinforcing steel
The formula above has been expressed on the nomograph (Figure 13-1) for a steel yield strength ys of
413.7 MPa (60,000 psi), and the maximum length or width can be obtained from the intersection of a
straight line drawn between the values of design thickness and percent steel that will be used for the
reinforced concrete pavement. The width of reinforced concrete pavement will generally be controlled
by the concrete paving equipment and will normally be 7.6-12.1 meters (25-40 feet), unless smaller
widths are necessary to meet dimensional requirements.
d. Limitations to Reinforced Concrete Pavement Design Procedure. The design procedure for
reinforced concrete pavements presented herein has been developed from a limited amount of
investigational and performance data. Consequently, the following limitations are imposed:
(1) No reduction in the required thickness of plain concrete will be allowed for percentages of
steel reinforcement less than 0.05.
(2) No further reduction in the required thickness of plain concrete pavement will be allowed
over that indicated for 0.5 percent steel reinforcement in Figure 13-1 regardless of the percent steel
(3) No single dimension of reinforced concrete pavement slabs will exceed 30.5 meters
(100 feet) regardless of the percent steel used or slab thickness.
(4) The minimum thickness of a reinforced concrete pavement or overlay will be
152 millimeters (6 inches).
REINFORCEMENT TO CONTROL PAVEMENT CRACKING.
a. General. Reinforcement is mandatory in certain pavement areas to control or minimize the
effects of cracking. The reinforcing steel holds cracks tightly closed, thereby preventing spalling at the
edges of the cracks and progression of the cracks into adjacent slabs. For each of the following
conditions, the slabs or portions of the slabs will be reinforced with 0.05 percent steel in two directions
normal to each other unless otherwise specified. No reduction in thickness will be allowed for this steel.
b. Odd-shaped Slabs. It is often necessary in the design of pavement facilities to resort to odd-
shaped slabs. Unless reinforced, these odd-shaped slabs often crack and eventually spall along the
cracks, producing debris that is objectionable from operational and maintenance viewpoints. In addition,
the cracks may migrate across joints into adjacent slabs. In general, a slab is considered to be odd-
shaped if the longer dimension exceeds the shorter one by more than 25 percent or if the joint pattern
does not result in essentially a square or rectangular slab. Figure 13-2 presents typical examples of
odd-shaped slabs requiring reinforcement. Where practicable, the number of odd-shaped slabs can be
minimized by using a sawtooth fillet and not reinforcing.