Au centre de la fosse de protection sismique du tokamak, seize niveaux de ferraillage circulaire et linéaire sont superposés à l?emplacement précis où sera assemblée
There are two types of bars present in the slab

1- Main bars

2- Distribution bars (bars provided against shrinkage and temperature)

Maximum spacing Between Individual Bars

1- The maximum diameter of the bar used in the slab should not exceed 1/8 of the total thickness of the 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, the diameter of the bar, the thickness of the slab, effective depth and spacing are co-related.

Effective depth = depth of slab – clear cover- half of the diameter of the 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 the 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 and

3- 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)

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