Why torsion steel is provided in slab?

Corner reinforcement are also called as torsional reinforcement. Torsional reinforcement shall be provided at corner of two way slab. The torsional moment are high near the corner therefore, torsional reinforcement is essential to prevent corner slab from lifting and prevents cracks.

In which slab torsion reinforcement is not provided?

Torsional reinforcement need not be provided at any corner where both edges are continuous.

In which slab torsion reinforcement is provided?

The torsion reinforcement shall be provided at any corner where the slab is simply supported on both the edges meeting at the corner.

What is the condition for one way slab?

If L/b the ratio is greater than or equal 2 or then it is considered a one-way slab. If L/b the ratio is less than 2 then it is considered a two-way slab. In one-way slab, the load is carried in one direction perpendicular to the supporting beam.

What is the minimum dia of bar?

As per IS 456:2000, in rcc slab, minimum diameter of main bar should not be less than 8mm (highly yield strength deform bar HYSD) or 10mm (plain bar) and distribution bar should not less than 8mm.

What is the minimum reinforcement in slab?

Minimum reinforcement in slab In slab, minimum reinforcement shall be 0.12\% of gross sectional area (B×D), taking B= 1m width of slab and D= overall depth including cover, then minimum reinforcement will be = 0.12/100× × 100× D = 0.12D sq. cm.

What are the rules for providing torsional reinforcement in two way slab?

Torsion reinforcement shall be provided at any corner where the slab is simply supported on both edges meeting at that corner and is prevented from lifting unless the consequences of cracking are negligible.

What are the Codal recommendation of torsion steel in two way slab?

The total area of torsional steel provided in each of the four layers should not be less than: (i) 0.75 Astx(+ve) If both the meeting edges are discontinuous i.e. edge 1. (ii) 0.375 Astx(+ve) If one of the two meeting edges, one is continuous and the other discontinuous i.e. edge 2 and 3.

Why torsion is provided in two way slab?

What are the differences between one way slab and two way slab?

Difference between One Way Slab and Two way slab:

One Way Slab	Two Way Slab
Loads are carried along one direction in one way slab.	Loads are carried along both the directions in two way slabs.

What is torsion reinforcement in concrete slab?

At corner C1 – The slab is discontinuous on both the sides, the torsion reinforcement shall consist of top and bottom bars each with layers of bar placed parallel to the sides of the slab and extending a minimum distance of one fifth of the shorter span from the edges.

Why corner steel is provided in a two way slab?

To resist that corner steel is provided. Corner reinforcement are also called as torsional reinforcement. Torsional reinforcement shall be provided at corner of two way slab. The torsional moment are high near the corner therefore, torsional reinforcement is essential to prevent corner slab from lifting and prevents cracks.

What is the torsional moment of a slab?

Torsional moment is the moment that leads to rotation of the plane about the axis. Mxx torsion would twist the slab about x-axis and Myy torsion would twist the slab about y-axis. These torsional moments are high near the corner of the slab.

What is the reinforcement in two way slab?

In two way slab main reinforcement is provided along both direction. Slabs could be simply supported, continuous or cantilever. In two way slab the corners may be held down by restraints or may be allowed to lift up. Additional torsion reinforcement is required at corners when it is restrained against uplifting as shown in Fig.1.