Lec 05

[Music] [Music] Hello, welcome again. Today we are on lecture five in this course on Principles of Construction Management under the MOOCS initiative of the Government of India. Our focus will be on the estimation quantities i.e. the quantity of any activity or work. The modules of this course on which we are discussing are shown here and out of this, the first module which was Introduction and Panoramic Image or View, our discussion on that has ended, today we are Starting the discussion, estimating the cost of projects i.e. discussing how much cost will be incurred in any construction work is the main objective of this module. Under that, today we will talk about estimating or estimating the amount of activities when we estimate the cost in the project. If we talk about the estimation of construction work, then two things should be kept in mind, one is that what are the different items or activities in that project, identify them and make a list of them. After identifying the activities, it is discussed about them. The quantity of activities, how much will that activity be, if it is earthwork, how much will it be, how much will be brick work, how much will be concrete, how much will be structural steel erection, how much is how many tonnes, then it gives us an idea of ​​various things, it helps us in the cost of the project. To estimate the quantity, once we know the quantity, then we should know what is the rate of those items or activities. Earthwork. If we know that it is 100 cubic meter then how much will it cost to do one cubic meter of earthwork. If we know this If this is possible then we can find out the cost of earthwork, calculate it and where will we get this rate from. Standard rate means there are some published documents in which the rates of commonly used activities are published and that They are revised every year or every two years, as inflation increases or decreases. Whatever happens, those rates are revised and published. They are published by the government. Every company calculates its rates and keeps its address. Manufacturing companies have to wonder how much does it cost to do this activity. If there is an item whose details are not available in the published literature, then we have to do rate analysis of that item. What are the things developed in that activity, what do we have to do and what are the rates of all those activities? Then we decide the rate of that activity through rate analysis and what does this rate depend on? On the details of the work to be executed, like flooring, if we look at it, there will be square meters on the flooring. From where will the rate of flooring be decided, it will be decided whether we will do mosaic flooring in it, Kota stone or tile installation, then this is the work done. A rough principle for estimating the cost of the project is that first of all we should know the activities, their quantities and their rates. Our topic today is how to calculate the quantities of activities. To calculate the quantity of activities, it is necessary to know their units. There are many types of measurement. Area is Volume, Volume is Length, Weight is Number. For example, in construction works, the activities are based on area. Activities include plaster, flooring, shuttering, all these things. The unit of these activities is square meter. Earth work or concrete. Its unit is cubic meter. Volume is pipes. How many meters will be used. Reinforcement i.e. rebar is estimated according to the weight. Lift is There are windows, there are doors, their unit count is how many windows will be installed in any building, what type will be installed, how many doors will be installed, how many lifts will be installed, it is not measured in area or volume but according to the count, as I said earlier, as far as cost is concerned. If the quantity and rate are known then the mathematics becomes very easy. For example, if we look at this table, if we know that Earthwork Plaster Pipes Concrete Structural Steel their quantity is 100 cubic meter 500 square meter 5 meter 600 Cubic meter is 15 ton and the rate of these activities in rupees is 50 per cubic meter, if we have earthwork then earthwork will be in 000 per square meter. If we have plaster, then to plaster 500 square meter we will have to pay ₹ lakh rupees. In this way, if we know the list of activities, their quantity, their rate, then we will know their respective costs and very easily we can estimate the total cost of the project. Now the question arises that this quantity Where will we get it starts from here? Before going there, before estimating the quantity, I want to share a few more things with you, that is, see the actual cost is known only after the construction is completed, whatever cost we They estimate at the beginning of the project that okay this is a project, it is estimated that it will cost two lakh rupees, two crore rupees, it will cost 200 crore rupees. Any construction work is not done in the manner of a watch or in the manner of a mobile phone. That we know that this mobile phone will be available in Rs 5499, that kind of thing cannot be done in construction work, it is very difficult, the actual cost is known only after the construction work is completed, then we come to know what was the quantity or how much quantity. Some things are fixed, windows and doors are fixed but how much earth work was done, how much concrete was done, how much shuttering was done, it can be estimated according to the drawings but in reality there are many reasons due to which the actual figures differ from the estimated figures. There is variation at Rs 5 at Rs 10 and Rs 2 and at the same time there can be variation in the rates too because as we had said earlier the construction work lasts for many years so to say that the price of steel which we carry today is suppose to be Rs 00. Tons or 15000 tonnes, whatever it is, it will remain double even after four years. This is a big problem, then this uncertainty itself makes the management of construction work a challenge. Let us move ahead. There can be a difference between the estimated and actual quantity of any activity. But we just talked about that the payment made by the customer i.e. the owner to the contractor is decided according to the type of contract. We will discuss this when we talk about the types of contracts, what types are there in a construction project. We will discuss later on how contracts are made and how an owner or a client organization makes payment to a contractor, but for now, let us take the example of a boundary wall which we have discussed earlier. We will discuss the process of estimating or estimating. We will use the drawings that we have seen earlier and will calculate the quantity of various activities and activities. We have seen this picture earlier also. This is the boundary wall that we will make. Our project is to make this boundary wall which is in an area of ​​20 meters by 10 meters. There is a provision to install a gate of 5 meters in it. We have decided that this boundary wall will be made of 230 by 300 mm RC pillars which will be at a distance of two and a half meters. In between, there will be a selection of brick work, that is, we will make this type of boundary wall. Here is the second view of this boundary wall, where we saw that these will be our concrete pillars, this will be a selection of our brick, on which we wrote Brick Work. With this, we will put an angle here, these will be our bob wires, so all these things, the client has decided that we want to make this type of boundary wall, so now the question comes that what should we need to make this boundary wall. What activities should be kept in mind and other details while making it, it is shown here about the RC pillar and foundation, what size is the RC pillar which is a concrete pillar, its footing is 800 by 800 mm, its foot is 300 Its size is and the rebar is tied to it as per the details given in the picture and the details of the rebar are given more clearly in this picture where we are taking a section here to see what type of rebar is there in this pillar. If you look at the details of this also, it is detailed where we are seeing how these stir ups have been folded. Why are we giving all this information? We are discussing this because steel When we calculate the quantity, we should know what diameter the steel is and how much quantity of steel we need. So if we look at this picture, here we are talking about 16 mm diameter and here we are talking about 12 mm diameter. We are talking about 8 mm diameter here, so from here we will know that later we will calculate that in what length do we need 8 mm, 12 mm or 16 mm rebar and when we weight it. If we convert it into , then we will get the total requirement of steel i.e. how many kilos or how many tons of steel do we need, how much steel will it be of 8 mm or 12 mm or 16 mm, this will come out from there. Let's move ahead and we will see the brick. On the work side, in brick work, we saw that the client has decided that there will be 15 mm thick plaster on both sides on this side of the wall and on this side of the wall and till how far this plaster will go down, we should know all these things Brick The work will cost one three rupees, plaster will cost one six rupees, because if we do not have these details, then we cannot make any kind of correct assessment. Another activity is visible here, another activity is visible, one more. The object visible is PCC. When we talk about concrete, the concrete is reinforced concrete, which is called reinforced concrete, in which rebar is used to increase its strength in tension or its carrying capacity. Plain concrete and In which rebar is not used, there is a provision to put plain cement concrete below the ratio of one aa. If you look carefully, there is a provision to put PC below the footing also. Let's move ahead and see. In this example, while calculating, it has been assumed that there will be no change in the ground level on either side of the boundary wall. What does it mean if our land is here, this is the level of our land. We will make a boundary wall, here we will have to make a small pit, then we will back fill it. We have already discussed this, but the level of the ground will remain the same on this side and this side, so when we back fill the pit, it will Plaster will be done on both sides of the boundary wall at this level. Plaster will be done up to 100 mm below the ground level. Concrete pillars will also be plastered. All these things can be disassembled in any way. We can say that the plaster will be done from the ground level. It will be 200 mm or up to 500 mm above the ground level. You can say anything but if we decide the details in advance and execute it, then the difference in our quantities between actual quantity and estimated quantity will be reduced to that extent. Regarding the angle, it is said in it that the angle of 100 by 100/8 mm will be embedded 150 mm in the RC pillar, that is, our RC pillar will come like this, that angle will be embedded at the bottom and this embedment length will be 150 mm. If mm is taken, it will go up by 400 mm to pull the wire over it, then it will be 400 mm, that is, the total length of the angle piece that we will put in the RC pillar should be 550 mm. We get this type of information from the drawing or from the given condition. Four layers of barbed wire will be placed at a 100 mm center to center angle, that is, in this angle, these four layers of barbed wire will be placed around the boundary wall. To calculate the excavation, an additional 200 mm will be taken on both sides from the required minimum width. What about this? This means that if we need this dimension to make a foundation below the foot here, then one way is that if this is our ground level, if this is our ground level, then to make this foundation we will have to dig at least this much. What has to be done is that it is said here that 200 mm more than this minimum width should be taken on both sides, that is, we should dig 200 mm more from here. Why is this 200 mm taken or why should only 200 mm be taken? It can also be 400, why not 500. There can be different kinds of things on this. The general principle is that here we need some working space so that if we remove this footing here, then it is not right to say that we will be able to dig such a deep pit directly. Due to the condition of the land and the properties of the soil, sometimes it is not possible to dig such a vertical pit, then what we have to do is that we have to take the pit in this shape, there are different types of things. That will be seen at the time of construction work but for now the condition given here for assessment is that we will increase the quantity of excavation by 200 mm and all the concrete work will be done in M25 grade concrete. This is when we are talking about M25 grade. So we are talking about pillars. Footing is written separately. RC Pillar 800. In 800 is isolated footing. We have just seen this in the previous drawing. Wherever required, clear cover will be considered as 40 mm. Clear cover is what is reinforced concrete. While doing the work, if our column or beam is of this cross section and the rebar is installed here, then this distance from the surface of the reinforcing bar is called cover. Why do we need the information about this cover? It is necessary to find out the quantity. That if our footing is of such a type in which this rebar is to be installed, then in the shape of this rebar, what will be this dimension or this length, is it less than the dimension of this footing, how much less is that, we have to decide by looking at the cover. Therefore, the more we can incorporate these small things while estimating the quantity, the more accurate our quantity estimation becomes. Let us move ahead and try to calculate the quantity of various activities in this boundary wall. First Activity Or the activity we call digging is to calculate the quantity of excavation we will have to do below the ground level, whether it is the foundation of brick work or the foundation of our RC pillar. Then comes the brick work i.e. digging. So this is our brick work in which there is this section above the ground and below the ground its width has been increased to give it strength. Shuttering work is necessary for us in concrete because we have to give shape to the concrete, so in concrete This is a column and we will have to put shuttering on the footing. We will have to estimate how much shuttering we will have to put. Concrete work i.e. RC or PCC. So RC i.e. prestressed concrete. Reinforced concrete. That will be in our pillars and PCC will be in the footing here below on both sides as a leveling course. It has been discussed earlier that it is decided that plastering will be done on both sides of the boundary wall and also on the pillars and this plastering will be done up to 100 mm below the ground surface. We should know the total length of the barbed wire and At the same time we should know the quantity of steel rebar reinforcing bars. Now one question I want to leave for you is this is the quantities required to make this boundary wall. There is one quantity I have left in this I want you to think on that. And try to identify what has not been taken into account in making the boundary wall given in these pictures. In any contract, every effort should be made to account for all the activities. But if a mistake is made then this is the homework for you. Let us move ahead and start the actual estimation of these quantities. First let us discuss the earthwork. This is the table. This is a template of quantity estimation. In which we write the numbers length, breath height and quantity unit and then start writing the numbers about whatever activity we are talking about. You will see how we write the quantities of plaster, concrete and earthwork. How to write in the table and this is the remarks column in which the details are given about the numbers given in it or the values ​​given in it, how we reached there, it is explained so that if anyone wants to check it, then he can If you can check, when we discuss about earthwork, we consider it as one, we have only one number, we say that the total length of 60 meters is developed, where did that 60 meters come from, it is written here that it is 10 p. 20 P 10 P 20 That is, we assumed that we will do earth work all around in this manner. Breath i.e. its width, so how to do earth work. After seeing this drawing, we understood that we have to do an earth work in this manner, the length of which we have determined. Find out 60 meters. What should be its width? The width of this channel is 9 x 2 x x 2, that is, it is 200 mm, so we took extra and 900 mm is the width of our PCC. We will add 200 and 200 to the width of this PCC. So this is 1.3, what is the height i.e. what is the depth, in this case the depth is 2.5 225207 Where did this come from, from the ground level given, this is given 200, then we figured here 500 225 200 and 75 mm i.e. this total is our exc. The height of the vasion became 1.2. You can check its calculation yourself and because now we want to do it in volume, we multiplied it and our earthwork came to 93.6 cubic meters. Now to take this earthwork, we adopted a simple method that We had taken earthwork all around, here it is an opening of 5 meters, we should not take it, for this we said that we will take a number as deduction in which we will not do earthwork of 3.7 meters, why is it 3.7, our opening is 5 meters, out of that We will have to do some earthwork here and along it, so we took the middle portion that was left so that out of 3.7 meters, 1.3 meters and 1.2 will remain common. If we do not want to excavate this 3.7 meters, then this will be done by putting a minus sign. 5.77 is written and by adding it, let us discuss about [music], then what will we do for brick work. There can be many ways to calculate the quantity of brick work. You can calculate it in your own way which is taken in this example. That is footing one footing two footing three, we took three footings, what did we do in these three footings, we said that the length of each one is 2.2 meter, where did this 2.2 come from, 2.5 meter center to center, this was the distance given to us, from here this Concrete will be half of 230, 15 here, 15 here, so if we reduce it, it will become 2.2, then 2.2 is our length, which will be the brick work between the two RC pillars. Along with that, this number is 22. Why is the number 22 because we All these parts and these sub-sections have been considered separately, if you calculate its total, in the boundary wall of 50 and 55 meters, if we put concrete pillars at 2 meters center to center, then you will understand that we Ba section needs break work. We have broken down that Ba section in this way. What is its width? It is 2 meters above the surface. If we start from here then this 230 thick boundary wall is 2 meters from here till the top. Given is the total volume of the boundary wall of 2 meters. This is the total by sections. Footing below it is one footing two footing three. This is footing two footing. Its height is given here. Its width is given here. If we look at the quantity of each stage, we will have to make some deductions from it because wherever the RC pillar and footing will come, there will not be that much brick work. Its deduction is shown here and the quantity of total brick work. It is 4149 cubic meters. Here you should keep in mind that the quantity of brick work is taken in cubic meters. Sometimes the quantity of brick work is also taken in square meters but at that time we have to determine the width of the brick work. It is said that 230 thick brick work is so many square meters. 115 mm thick brick work is so many square millimeters. In India, especially in North India, walls are made of full brick and half brick. If a wall is made of full brick, then we call it 230 mm and half brick. If we take 115 mm in the wall of the T, then once we specify its width then we have no problem in giving the brick work in square meter because ultimately the objective is to know how many bricks will be required for the total brick work and how much mortar will be required. You should get an idea of ​​it in this particular example. In this example, we took the quantity of brick work because here the width was different and we had to make a rough estimate, so we have taken it in total cubic meters. Now we come to the concrete work, forced concrete. First let's calculate and estimate, we have to make 23 pillars and 23 footings, so this number becomes 23, its length is 23 and breath because we said 23 * 300 and its height is 2.67 which we got from the drawing here. If we come to the top boundary wall where the elevation is 1.8, then 1.8 which is the top of the boundary wall and 875 mm of that boundary wall here, if we add it then it will be 2.67, so in this way the height of this pillar will be 2.67. By using this we calculate the quantity of total reinforced concrete coming in the pillar 4.25 In the same way, 2 footings will be made which will be P8 in P8, their thickness or height is 25, it is given in this diagram or this picture. We calculate the quantity of fitting as 3.68 and our total reinforced concrete work came to 7.93 cubic meters. Similarly, if we talk about PCC, for plain cement concrete, we took 60 meters of PCC. The way we calculated the earthwork, in the same way we calculated here. Also taken as 60 meter 9 This is its width which was shown last time in a drawing here but not in this drawing 075 Its height was considered to be 75 mm and PCC became 4.05 cubic meter but in doing this PCC because here we have taken 60 meter Therefore, we will have to deduct 4.1 meter and by taking this deduction, our calculation will be 27 cubic meter and total net PCC will be 3.78, so in this way we have calculated the quantity of reinforced concrete and plain concrete in this slide. Keep in mind that we have While calculating the quantity of reinforced concrete, the amount of steel used in the reinforcement bar, even if it is in the footer column below, its volume has not been subtracted. This is a convention. If you want to calculate it yourself, then you will see that the quantity is very less. Therefore, no provision for reduction is taken in the estimation, so with this we would like to end today's lecture here. Today we have taken the example of this boundary wall by taking the example of excavation and have calculated the quantity of concrete work. In the next lecture we will talk about shuttering plaster. We will discuss the total length of barbed wire and steel bars. To understand in more detail the material which we have discussed today in useful published books, I would suggest you to read BN Dutta's book Estimate and Costing and Civil Engineering. Read Three and Practice Thanks Jai [Music] [ Music] [Music] Hindi