Minimum thickness of RCC slab as per IS 456, hi guys in this article we know about thickness of rcc slab, RCC slab is Flat surface laid over brick wall made of mixture of cement sand aggregate provided with reinforcement.
Minimum thickness of a slab is completely dependent upon the types of slab, may be one way or two way slab, span of slab, design load upon the slab. But, the thickness is mostly depend upon the design load and the span. Other than that, the concrete mix grade also an important factor to the thickness of slab.
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The actual thickness of slab is find out at the time of designing the slab and preparing the BBS (Bar Bending Schedule).
Thickness of RCC slab:-In general, 6 inch (150mm) is rcc slab thickness is considered for residential and commercial buildings with reinforcement details as per design.
Slab thickness in mm:- standard slab thickness in mm for RCC roof slab should be minimum 125 mm thick for residential building, 150 mm thick for commercial building, 75 mm thick for footpath, 100 mm for Patios, 150 mm for driveway and parking area and for ground bearing concrete floor slab for residential house should be 100 mm thick.
Slab thickness in cm:- standard slab thickness in mm for RCC roof slab should be minimum 12.5 cm thick for residential building, 15 cm thick for commercial building, 7.5 cm thick for footpath, 10 cm for Patios, 15 cm for driveway and parking area and for ground bearing concrete floor slab for residential house should be 10 cm thick.
Slab thickness in inch:- standard slab thickness in mm for RCC roof slab should be minimum 5″ thick for residential building, 6″ thick for commercial building, 3″ thick for footpath, 4″ for Patios, 6″ for driveway and parking area and for ground bearing concrete floor slab for residential house should be 4″ thick.
Minimum thickness of slab
Minimum thickness of rcc slab is 4″ or 100mm, 3″ for side walk, 4″ for patios, 6″ for driveway and minimum 4″ thick for parking. It will be restricted to 4 times the nominal size of aggregate. For example, in 20mm nominal size aggregate is used in concrete , the minimum thickness is limited to 80mm according to Cl 5.3. 3 of IS 456:2000.
Here I am going to give the recommendations mentioned by codes.
1) AS per ACI (AMERICAN CONCRETE INSTITUTE) the minimum thickness of rcc slab should be 5 inches.
2) As per IS 456-2000 the minimum thickness of RCC slab is restricted to 4 times of nominal size of aggregate.
Let me say, an assumption, from my practical work experience, in general case,
Minimum concrete cover = 3/4 inch bottom, 3/4 inch top
dia of #4 bar = 1/2 inch main bar, 1/2 inch distribution bar
dia of binding wires = 0.16mm-0.6mm per layer
min thickness for concrete aggregates = 1/2 inch to 3/4 inch
precautionary thickness for pouring aggregates = 1 inch
minimum thickness should not be less than 4.75 inches not forgetting factor of safety.
Standard concrete floor slab thickness is residential construction is 4 inches, five to six inches is recommended if the concrete will receive occasional heavy load, such as mortar homes or garbage trucks.
