Points to be taken care of slab reinforcement
There are two types of bars present in the slab.
Main bars
Distribution bars (bars provided against shrinkage and temperature)
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 and
5 mm more than the nominal maximum size of coarse aggregate.
Clear cover (Nominal Cover) shall be kept in mind while calculating the above parameters.
Source: IS 456 (2000)
There are two types of bars present in the slab.
Main bars
Distribution bars (bars provided against shrinkage and temperature)
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 and
5 mm more than the nominal maximum size of coarse aggregate.
Clear cover (Nominal Cover) shall be kept in mind while calculating the above parameters.
Source: IS 456 (2000)
