Maximum spacing between Individual Bars:
- The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab.
- For main bars, maximum spacing is restricted to 3 times effective depth or 300 mm whichever is smaller.
- For distribution bars, the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is smaller.
Hence, diameter of bar, thickness of slab, effective depth and spacing are co-related.
Effective depth = depth of slab – clear cover- half of diameter of bar
Minimum Distance between Individual Bars:
Minimum Distance between Individual Bars & main reinforcing bars shall usually be not less than the greatest of the following:
The following shall apply for spacing of bars:
- The diameter of the bar if the diameters are equal.
- The diameter of the larger bar if the diameters are unequal.
- 5mm more than the nominal maximum size of coarse aggregate.
Clear cover (Nominal Cover) shall be kept in mind while calculating the above parameters.