What should be the Spacing of Reinforcement among various reinforced concrete members

Lowest Spacing Among Bars in Tension: The least horizontal spacing among two parallel main bars will be determined as follow :-

The diameter of bigger bar or maximum size of coarse aggregate + 5 mm.

In case, the compaction is performed with needle vibrator, the spacing may be again decreased to two-third of the nominal maximum size of the coarse aggregate.

The least vertical distance among two main bars should be as follow :-

(a) 15 mm,
(b) two-third of the nominal size of coarse aggregate, or
(c) maximum size of the bar or whichever is higher.

Highest Spacing among Bars in Tension

Usually these spacing are as follow :

(a) For beams, the gapping should be 300 mm, 180 mm and 150 mm for grades of main reinforcement of Fe 250, Fe 415 and Fe 500, correspondingly.
(b) For slabs

(i) the highest spacing among two parallel main reinforcing bars should be 3d or 300 mm or whichever is less, and
(ii) the highest spacing among two secondary parallel bars should be 5d or 450 mm or whichever is less.

Reinforcement Requirement in Members:

Beams:

(a) Least tensile steel is presented with the ratio (For Flanged Beams b= bw)
(b) Highest Tensile Reinforcement in Beams should be under 0.04 bD.
This reinforcement should be uniformly allocated on two faces at a gapping not surpassing 300 or web thickness or whichever is less.
(c) Highest area of compression reinforcement should be under 0.04 bD.
(d) Beam with depth over 750 mm, side face reinforcement of 0.1% of web area should be arranged.

This reinforcement should be uniformly allocated on two faces at a gapping not surpassing 300 or web thickness or whichever is less.