UFC 3-260-02

30 June 2001

(2) Wire fabric will be overlapped for a distance equal to at least one spacing of the wire in the

fabric or 32 wire diameters, whichever is greater. The length of lap is measured from the tip of one wire

to the tip of the other wire normal to the lap. The wires in the lap will be wired or otherwise securely

fastened to prevent separation during concrete placement.

9.

JOINTING.

a. Requirements. Figures 13-4 through 13-6 present details of joints in reinforced concrete

pavements. Joint requirements and types will be the same as for plain concrete except for the following:

(1) All joints will be doweled with the exception of thickened-edge-type joints and longitudinal

construction joints. One end of the dowel will be painted and oiled to permit movement at the joint.

(2) Thickened-edge-type joints (expansion, butt, or slip) will not be doweled. The edge will be

thickened to 1.25hd.

(3) When a transverse construction joint is required within a reinforced slab unit, the reinforcing

steel will be carried through the joint. In addition, dowels meeting the size and spacing requirements of

Table 12-8 or the design thickness hd will be used in the joint.

b. Joint Sealing. Joint sealing for reinforced concrete pavements will be the same as for plain

concrete pavements.

10. EXAMPLES OF REINFORCED CONCRETE PAVEMENT DESIGN.

a. A reinforced concrete pavement is to be used for an Air Force heavy-load airfield. Field and

laboratory test programs have yielded design values of 4.8 MPa (700 psi) for the concrete flexural

strength R and 54 MN/m3 (200 pci) for the modulus of soil reaction k for the foundation.

b. Assuming that stabilization will not be used, it is first necessary to determine the required

thicknesses of plain concrete pavement. By entering Figure 12-8 with the design values of R and k, the

required thicknesses of plain concrete are as shown in column 2 of Table 13-1. At this point, it is

necessary to decide whether to preselect the percentage of reinforcing steel and determine the required

thickness of reinforced pavements, or to select a thickness of reinforced concrete and determine the

percent steel. First, let it be assumed that a S = 0.20 percent will be used and that it is desired to

determine the required thickness. Figure 13-1 is entered with S = 0.20 percent and the thickness of

plain concrete for each traffic area, and values of reinforced concrete pavement thickness determined as

shown in column 3 of Table 13-1. These thicknesses are rounded to the nearest 10-millimeter (-inch)

increment for construction (column 4). After the thicknesses are rounded, it is then necessary to reenter

Figure 13-1 to determine the percent steel commensurate with the rounded thickness values (column 5).

Next, let it be assumed that types A, B, and C traffic areas are to be constructed to the same thickness

of 405 millimeters (16 inches) of reinforced concrete pavement, and type D traffic areas are to be

255 millimeters (10 inches). Figure 13-1 is entered with the thickness of plain concrete and selected

values of reinforced concrete thickness to determine the required percent steel (column 7). The

maximum length or width of a reinforced concrete pavement slab is a function of the yield strength of the

steel, thickness of the slab, and percent steel and can be determined either from Figure 13-1 or by

Equation 13-1. Columns 6 and 8 of Table 13-1 present the maximum allowable lengths or widths for the

examples using a steel with a yield strength of 413 MPa (60,000 psi).

13-6

Integrated Publishing, Inc. |