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South African Pavement Engineering Manual
Chapter 10: Pavement Design
(iii) Determine Relative Vertical Movement at Joints or Cracks
The next step is to determine the relative joint or crack movement, using the nomograph in Figure 51. This
nomograph requires the spacing of dowel bars and the dowel bar diameter, and/or the crack/joint spacing and
maximum aggregate size in the concrete mix. The minimum movement from the two nomographs in Figure 51 is
used.
Figure 51. Relative Movement at Joint
(iv) Determine Slab Thickness
The final step in the concrete slab design is to determine the slab thickness required. This is done using the
nomograph in Figure 52, which uses the:
• Equivalent single 80 kN axle loads from Figure 49 and the number of each load group
• Equivalent support stiffness from Figure 50.
• Concrete flexural strength
• Relative joint movement
• Type of concrete pavement is shown to give an indication of the expected movement
Section 7: Structural Capacity Estimation: Concrete Pavements
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