In the design of two-way slab restrained at all edges, torsional reinf...
For restrained slab, the area of reinforcement in each of the four corner layers shall be three-quarters of the area required for the maximum mid span moment in the slab simply supported on both edges meeting at that corner. If the corner contained by edges over only one of which the slab is continuous, torsion reinforcement equal to 0.375 times the area of reinforcement provided the mid-span in the same direction shall be provided. If both edges are continuous, no torsion reinforcement shall be provided.
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In the design of two-way slab restrained at all edges, torsional reinf...
Torsional Reinforcement in Two-Way Slab
Two-way slabs are structural elements that are used to transfer loads in two directions to the supporting beams or columns. When designing a two-way slab that is restrained at all edges, torsional reinforcement is required to resist the twisting forces that may occur due to the applied loads. The amount of torsional reinforcement required is determined by the following equation:
As = 0.75Ast,mid
Where As is the area of torsional reinforcement required per unit width of the slab, and Ast,mid is the area of steel provided at midspan in the same direction.
Explanation of Answer
Option A is the correct answer because it provides the equation that is used to determine the amount of torsional reinforcement required in a two-way slab that is restrained at all edges. The equation states that the area of torsional reinforcement required is 0.75 times the area of steel provided at midspan in the same direction. This means that the amount of torsional reinforcement required is proportional to the amount of steel provided at midspan, which is the location where the bending moment is maximum in both directions.
Options B, C, and D are incorrect because they either provide a lower value for the amount of torsional reinforcement required or suggest that no torsional reinforcement is required, which is not accurate for a two-way slab that is restrained at all edges.
Conclusion
In conclusion, when designing a two-way slab that is restrained at all edges, it is important to consider the amount of torsional reinforcement required to resist the twisting forces that may occur due to the applied loads. The amount of torsional reinforcement required is proportional to the amount of steel provided at midspan in the same direction and can be determined using the equation As = 0.75Ast,mid.