# Important Notes On Slab (Spacing, Effective Depth Etc)

|## Important Notes On Slab:

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:**

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 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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- One Way Slab Design – How To Design One Way Slab
- Design Of Columns As Per ACI
- Reinforcement Details In Beams And Slabs
- Minimum Cover For Reinforcement in Cast-In-Place Concrete

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