CHAPTER 10. DETAILING
Fig. 10.21. Minimum number of bars
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For a distance equal to the larger dimension of the column, above and below slabs or beams the spacing noted above should be reduced by a factor of 0.6. The above reduced spacing is also required at laps of longitudinal bars of diameter greater than 14 mm. A minimum of three transverse bars should be evenly positioned over the lap length.
10.9.4. Walls Vertical reinforcement (1) Minimum area Asv, min Asv, min = 0.002Ac (2) Maximum area Asv, max: Asv, max = 0.04Ac The code permits this to be doubled if the designer can show that the integrity of concrete is not affected and the full strength can be achieved at the ultimate limit state. (3) Maximum spacing Smax: – The distance between adjacent bars should not exceed three times the thickness of the wall or 400 mm, whichever is less. (4) When minimum reinforcement controls the design, 50% of the minimum reinforcement should be placed on each face.
Horizontal reinforcement (1) Placement: – Horizontal reinforcement should be placed between the vertical reinforcement and the face of the wall. (2) Minimum area Ash, min: Ash, min = 0.25Asv but not less than 0.001Ac. (3) Maximum spacing Smax: Smax = 400 mm (4) Minimum diameter: – The code does not specify a value, but it will be prudent to use a minimum of 0.25 times the diameter of the vertical reinforcement.
Transverse reinforcement Where the area of vertical reinforcement exceeds 0.02Ac transverse reinforcement in the form of links should be provided in accordance with the requirements for columns.
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