We recently calculated the material cost for a RCC PIER of a bridge.
In the beginning , we drew the basic section through this PIER.
Remember , in Bridge , there are no columns .rather , a column which supports the super structure of a bridge is known as PIER.
You shall observe that in the Cross section ,
we have changed the basic geometry of the Pedestals and the Pier.
DIMENSIONS HAVE BEEN ASSUMED FOR THE PURPOSE OF THIS EXERCISE.
Next , we also drew the PLAN of this PIER.
Remember : Plan means TOP view .
Next , we wrote the measurements of the individual components of this PIER.
The components are :
[ From top most portion downwards.]
- Bearing Pedestals [ RCC M 40 ]
- Main Pedestal [ RCC M 35 ]
- Pier [ RCC M 35 ]
- Pier Foundation :[ RCC M 35 ]
- Levelling course [ PCC M 35 ]
The measurement sheet appeared like this :
Now , for calculating the material consumption , we needed the material constants for the various concrete mixes used in this PIER. Since we did not have the data of the actual design mixes , we used dry mix method to arrive at the material constants.
Remember : Material constants are the material consumption per unit volume of that concrete mix.
The calculations sheet appeared like this :
Now we just needed to multiply the volumes of different grades of concrete with the material constants just calculated.
Here is that sheet :
Now we need to just summarize the material required in different components.
In the same sheet , we multiplied the quantities by the assumed unit rates of the materials.
Then we realized that we had forgotten to add the quantity and cost of the Plasticizers to be added in the various grades of concrete.
That we added like this :
Thus , the total material cost [ excluding Reinforcement steel , binding wire , worked out to be : Rs.3,72,372 .
Having wrote this , I thought , why not to add the material cost for Reinforcement steel , and binding wire also .
In absence of the RCC design ,Let me assume that such type of PIER shall consume @ 100 Kg /Cum of Re bars.
Therefore , the quantity of Re bars works out like this :
RCC M40 : 0.125 CuM
RCC M35 : 65.25 CuM.
Total RCC volume : 65.375 CuM.
Weight of Re bars : 65.375 CuM.* 100 Kg / Cum = 6537.5 Kg. [ 6.54 MT ]
Rate of Rebars assumed @ Rs.40,000 per MT.
Cost of Re bars = 6.54 * 40,000 = Rs.2,61,600
We also need to add the cost of binding wire in this.
Binding wire needed per MT of Re bar : 10 Kg.
Consumption of Binding wire : 6.54*10 Kg = 65 Kg.
Rate of binding wire : Rs.50 per Kg.
Cost of binding wire : 65*50 =Rs.3250
Thus , the total material cost becomes :
- RCC : Rs.3,72,372 .
- Re Bars : Rs.2,61,600
- Binding wire : Rs.3250
Total material cost : Rs.6,37,222 / =
Hope you have understood the basic sequence to be followed.
In this example, we have made some assumptions .When working on the actual estimate , you can certainly work with the actual material rates prevailing at your site.
Also note that we also need to add the :
- Labour cost
- Supervision charges ,
- Tools and Plants
- Administrative charges
- Specialized cost for the shuttering to be done
- Wastage in various materials
- Miscellaneous items
- Profit of the contractor
Which we shall learn in another article.
Thank you so much for reading this article.