Table of Contents
Why extra steel is provided in slab?
1. To resist negative bending moment (hogging). 2. To resist shear force which is greater at supports.
Why do we need minimum reinforcement in slab?
A minimum area of reinforcement is required to control the cracking, which occurs in the concrete due to temperature, shrinkage and creep. It enables cracking to be uniformly distributed and therefore minimizes individual crack width.
Why cranks are provided in slab?
Cranked bars / Bent up bars are provided on top of the reinforcement to resist negative bending moment/Hogging at the supports of the slab. To resist the shear force at the supports. To reduce the risk of a brittle failure of slab-column connection.
What is the minimum steel required in slab?
0.12\%
Minimum reinforcement is 0.12\% for HYSD bars and 0.15\% for mild steel bars. The diameter of bar generally used in slabs are: 6 mm, 8 mm, 10 mm, 12mm and 16mm. The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab.
What is the diameter of bar used in slabs?
Diameter of bar generally used in slabs are 8 mm, 10 mm, 12 mm and 16 mm or more depending upon various factors. For example, loading pattern on slab, type of structures etc. In buildings, mainly diameter of bars used in slab are 8 mm, 10 mm and in some cases 12 mm.
What is the minimum diameter of a beam or slab?
Practically In slabs minimum of 8 mm diameter bar are use as main bar and minimum of 6mm bar is used as distribution bar. In beams if we design it as simply supported then minimum off 8mm bar can be used in top portion that is in compression zone and similarly in tension zone minimum off 10 mm can be used practically.
What is the purpose of slabs in construction?
Slabs are constructed to provide flat surfaces, usually horizontal in building floors, roofs, bridges, and other types of structures. The slab may be supported by walls or by reinforced concrete beams usually cast monolithically with the slab or by structural steel beams or by columns, or by the ground.
How to design the bottom steel of the slab?
Designing the bottom steel of the slab in the main direction is done exactly as a rectangular section (beam) taking a 1 meter sample width of the slab as your analysis block.