Why torsional reinforcement is provided in slab?

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 are the criteria for torsional reinforcement in slab?

1. Torsional reinforcement need not be provided at any corner where both edges are continuous. 2. Torsional reinforcement of 50 \% of three-quarters of the area required for maximum mid-span moment in the slab shall be provided at a corner contained by edges over only one of which the slab is continuous.

What is torsion reinforcement in two way slab?

Torsional reinforcement is provided in the form of a grid or mesh both at the top and bottom of the slab. i.e. lx/5. The total area of torsional steel provided in each of the four layers should not be less than: Astx(+ve) denotes the area of flexural steel required for maximum mid-span moment in the short direction.

What is the minimum thickness of slab?

Minimum Thickness of Slab The minimum thickness of the RCC slab is 4″ or 100mm, 3″ for sidewalk, 4″ for patios, 6″ for driveway, and minimum 4″ thick for parking. It will be restricted to 4 times the nominal size of aggregate.

How do you stop a torsion beam?

The best way to prevent this type of buckling from occurring is to restrain the flange under compression, which prevents it from rotating along its axis. Some beams have restraints such as walls or braced elements periodically along their lengths, as well as on the ends.

What is the maximum reinforcement in slab?

Maximum reinforcement in slab is restricted 1 to 2 \% of gross sectional area.

How is torsional reinforcement provided in beam?

On several situations beams and slabs are subjected to torsion in addition to bending moment and shear force. Loads acting normal to the plane of bending will cause bending moment and shear force. However, loads away from the plane of bending will induce torsional moment along with bending moment and shear.

When the slabs are subjected to torsional effect and corners are held down the?

But there are other types of two-way slabs which are not simply supported. For example, the two-way slab may be continuous over one or more supports. Fig. 17.1 that we saw earlier is the plan view of such an example.

When is torsion reinforcement required at corners of slab?

Additional torsion reinforcement is required at corners when it is restrained against uplifting as shown in Fig.1. Thickness of the slab is decided based on span to depth ratio specified in IS456-2000.

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.

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 standard thickness of reinforcement bars in slab?

Generally 15mm to 20mm cover is provided for the main reinforcements. Alternate main bars can be cranked near support or could be bent at 180 0 at the edge and then extended at the top inside the slab as shown in Fig.1. Curtailment and cranking of bars and is shown in Fig.