Minimum Percentage of steel is based on the type of structural member (compression, tensile, flexure, etc...}. It can't be for a per cubic meter.
Please refer Indian Standard IS 456-2000 code for further details.
For slabs: 0.5-1.5%
For beams: 1.5-2%
For Column: 2-3%
For RCC roads: 0.6%
For an example, let us take RCC column with reinforcement requirement of 2.5 % of concrete volume then weight of the steel required will be:
(2.5*7850)/(100*1) = 196.25 kg
Follow the IS 456:2000
We cannot say the percentage of the steel reinforcement to be used on the concrete (per cubic meter) because effective depth and b will be a factor of its ultimate moment
It depends upon the type of element into which your concrete would be used, like beam or column or slab. But as per IS 456 the minimum reinforcement of 0.12% the area of element should be provided
I assume that you want to interpret the amount of reinforcement you have in a particular reinforced-concrete section as a percentage of the concrete section. This is normally done in terms of area not volume of the reinforced concrete section. Simply work out the cross-sectional area of steel bars passing through the designed section and divide it by the cross-sectional area of the concrete through which it passes and multiply the result by 100. The result is As%.
Per your question, and for a RC beam for example, you should calculate the % of the longitudinal reinforcement which is done by dividing As/Ag and add the % of shear reinforcement which should be calculated depends on its spacing.
The simplest method is to use factors that convert the steel areas obtained from the initial design calculations to weights, e.g. kg/M2 or kg/m as appropriate to the element.
If the weights are divided into practical bar diameters and shapes, this method give a reasonably accurate assessment. The factors, however, do assume a degree of standardization both of structural form and detailing.
This method is likely to be the most flexible and relatively precise in practice, as it is based on reinforcement requirements indicated by the initial design calculations.
It is depends on type of element. And i agree with percents suggested by Girish Narayan Prajapati .
The actual and accurate calculation of reinforcement in the building proves to be vital in the over all incurred cost of the project. Exact and accurate estimations of the reinforcements are made from the building drawings and bar bending schedule. However for a pilot guess or when there is no availability of drawings and schedules, the quantity is normally described in accordance with some Thumb Rule which makes the requirements of the Standard Method of Measurement.
an approximate / average guess for first instance can be made using following table, (Values must be calculated later from drawings when available to find exact values)
RCC Building Element type :: Weight in Kg/cubic mtr
Bases :: 90 - 130
Beams :: 150 - 300
Beams loaded lightly :: 100-150
Beams (Caping) :: 130-140
Columns :: 200-450
Columns loaded lightly :: 110-200
Plinth Beams :: 230 - 300
Footings :: 70-100
Pile Caps:: 110-150
Ribbed floor slabs :: 80-120
One way slab :: 75-125
Two way slab :: 67-135
Flat Slabs:: 95 - 135
Raft footings:: 110-120
Retaining Walls :: 110-1850
Transfer slab :: 140-160
Stairs :: 130-170
Tie Beams :: 130-170
Shear Walls (normal) :: 70-100
Shear Walls (Wind load) :: 90-150
Piyush Sharma ...
its area of reinforcement required for one cubic meter of concrete.. in general for slab of 20cm thick.. we calculate the area for reinforcement per one square meter and multiplied by five.. and so on.. but its not a measured for any significant thing.. because this number will change according where you calculate the area of reinforcement.. mid or side ... Also its differ from slab to beam to column to other structure elements...
Regards..
Hi
how to calculate number of loops in connection(wall to wall) ?...
where i need to refer?...
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