What is the purpose of extra bars are provided in slabs?

You may provide extra bars if it is framed structure, and if the slab is monolithic with the edge beam due to fixity. Otherwise there may be some cracks will develop before the moment is thrown to the span from support. If it is simply supported say on masonry wall or so, then no extra bars are required.

What is distribution steel in slab?

Distribution steel is mainly provided on the top of the main bar, hence placed in longer span direction. The main purpose of providing distribution steel are used to hold the slabs on either way and to resist the cracks and shear stress developed at the top.

What is the difference between main bars and distribution bars?

Main Reinforcement Bars are used to transfer the bending moment developed at the bottom of the slab. Distribution Bars are used to hold the slabs on either way and to resist the cracks and shear stress developed at the top.

What is main bar in slab?

What are the main bars in a slab? The reinforcement bars that are placed in the tension zone of the slab to resist the bending moment & to transfer the superimposed loads to the supports that are provided for the slab are called main bars.

How do you calculate slab steel bars?

Steel Quantity Calculation (Cutting length) main bar: formula = (l) + (2 x ld) + (1 x 0.42d) – (2 x 1d), where l = clear span of the slab, ld = development length which is 40 d (where d is diameter of bar), 0.42d = inclined length (bend length), 1d = 45° bends (d is diameter of bar) first calculate the length of “d“.

What is extra bar?

1) Extra top bar are provided to increase tensile strength of beam ( to control negative moment) at support. 2) To resist diagonal tension stress and in order to prevent inclined cracks to occur by action of maximum shear stresses which concrete fails to resist.

Which slab thickness is minimum?

Minimum thickness should not be less than 4.75 inches not forgetting the factor of safety. Standard concrete floor slab thickness in residential construction is 4 inches, five to six inches is recommended if the concrete will receive occasional heavy loads, such as mortar homes or garbage trucks.

Which bars are called main bars in slab?

How do you calculate slab distribution bar?

Formula = (total length – clear cover)/center to center spacing + 1 main bar, = (5000 – (25+25))/100 + 1, = 4950 divided by 100 + 1, = 51 bars., distribution bar = (2000 – (25+25))/125 + 1, = 1950 divided by 125 + 1, = 17 bars.

What is the difference between Main and distribution bars in slab?

Main reinforcement bar is used to transfer the bending moment to beams. Distribution bars are used to resist the shear stress, and cracks developed at the top of the slab. Why Crank Bars Are provided In Slab?

What is distribution bar in steel reinforcement?

Distribution Bar: Mainly used in case of two way slab provided at top layer, main function of such bar is to distribute the load to main bar. Main steel reinforcement is the one place along shorter direction and the distribution steel is place along longer side.

What is distribution steel in slab construction?

In addition to this bars along longer dimension are also provided above main steel at right angle called as distribution steel.The distribution bars helps in resisting cracks due to variation of temperature and shrinkage stresses. They also assist in distribution of loads. Main reinforcement normally is used at the bottom of the slab.

What is the difference between shear bar and distribution bar size?

So there will be no difference in bar size because each side will have to transfer equal amount of stress evenly. 1. Distribution bars are provided to resist the shear stress, cracks developed in the longer span.