Maximum and Minimum Spacing Between Individual Bars on Slab

Maximum spacing between Individual Bars:

1. The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab.
2. For main bars, maximum spacing is restricted to 3 times effective depth or 300 mm whichever is smaller.
3. 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:

1. The diameter of the bar if the diameters are equal.
2. The diameter of the larger bar if the diameters are unequal.
3. 5mm more than the nominal maximum size of coarse aggregate.

Clear cover (Nominal Cover) shall be kept in mind while calculating the above parameters.