 Assistant Professor, Department of Civil Engineering, Walsh and Institute of Technology, Solapur. In today's session, we will see the regarding the project network crashing or compression. At the end of the session, the learner will be able to determine the direct cause associated with the particular activities as well as the indirect cause associated with the particular activity which will help to define the overall direct cause and the indirect cause associated with the projects. And he will able to determine the extra cause associated with the particular activity if they are going to be compressed. And finally, with the help of all this cost, he's going to determine the total project cost. Now the total project cost, the total project cost is nothing else. It is a particular summation of the direct cost as well as the indirect cost. As we observe in the project, there are n number of activities, or you can say the activities which are there in the particular project, they consume the resource. And this resource are finally termed in the term of the cost. So the total project cost is nothing else. It is a summation of direct cost plus indirect cost. When we see this flow chart, in the indirect cost, we see the overhead causes and the outage causes. Now, what are the direct costs? If I take the particular activity in the project, the direct costs are nothing else. The manpower, material, machineries and tools, finally, which are all, which are defined in terms of cost, or that is money. Yeah, there is a graph which is showing you the particular representation of the direct cost between the duration and the cost. Yeah, in initial stage, the particular cost of the, when we observe the direct cost of the project, it's at the higher level. As the execution goes on, the particular cost reduces. But if there is delay, again, it will be increased. Now, let's see indirect cost. The indirect costs are nothing else. The charge costs, which are associated with the office setup at the site, all the temporary facilities, like you can say, electric city, telephone bills, stationaries, and the equipments or construction machineries, which are required for the offices, like you can say, printing machines, fax, et cetera. And the cost, like project manager, like you can say, the insurance causes of the constructions, it may be related to the various resources which are involved in the projects. And finally, you may observe the indirect cost due to delay in the project also. It may be in terms of penalty, as the project has been delayed. Now, some of the points which I mentioned in this slide, which shows that these are some overrated costs associated with the particular project. As their main offices expenses came, the site office is different and the main office expenses is different. And other than that, the equipments and the vehicles and all the services, office services, which are not directly related to the particular project, but they are required like a lawyers or you can say accountants, et cetera. Now, when we observe this particular graph, the direct cost is a linear one. And when we sum the overhead cost plus the outage cost, we get the total indirect cost, as shown in the second graph, okay? This is the overhead cost. When we add the outage cost says with the particular indirect cost, we'll get the total indirect cost, which is in the curve form. But most probably it is considered as a linear one. Now, the cost loop is a point which helps us to determine the cost or you can say the extra cost to the particular activity per duration if we go for the compression of the activity. See, the direct cost time curve is actually the particular straight line or you can say the multi-straight lines or you can say segments. The cost loop is nothing else. It is, as I said, the particular cost associated with the activity per unit duration. These are the terms which are required for the finding out the cost loop of each activity. The first one is a normal duration. The duration required to finish the activity under the normal condition or you can say ordinary conditions or circumstance. And the normal cost, the cost associated with the particular activity, which is executed during the normal duration and the crash duration, that is the least possible duration required for the activity to complete the particular activity as well as project. And the crash cost is nothing else that is the particular cost which is determined as we crash the activity. And this is nothing else that is the additional cost which is associated with activity as we are crashing the or as we are reducing the duration of the activity. Some extra resource should be assigned to the particular activity. So that extra resource means what? Extra additional cost for the activity to complete or to execute. Now the formula for the cost loop is nothing else. It is equal to crash cost minus normal cost divided by normal duration minus crash duration, which is helping to make a decision regarding the selection of the activity for the crashing one. Now this is a particular direct cost curve as we have seen in the earlier slide. As I explained that in the initial stage, the direct cost of the project is at the higher level as the execution goes, as the time passes, the particular direct cost goes reducing. It reduces at a certain level, but if we delay the project, its cost increases. Now here we are observing that that this is a particular initial stage of the project. Okay, the curve starts reducing at a certain point, but if we delay the project, its direct cost increases. And here you observe that there is a particular point, the normal cost, normal duration, a crash cost and the crash duration. This is a total project cost. When we add both the direct cost as well as the indirect cost curves, or if we represent both the cost on the single graph, we get such kind of a graph. Here the blue color line is, or you can say the curve is nothing else, it's a direct cost and the brown color is nothing else indirect cost. And in the second graph, as we know the total project cost is nothing else, it is equal to direct cost plus indirect cost. So this is a direct cost curve plus indirect cost curve. This green color is nothing else, that is the curve which is representing the total cost or you can say total project cost. And here you are observing that this is a point at which there is an intersection of both the direct cost and the indirect cost. And this is a point from which we get the optimum cost as well as optimum duration of the particular project. Now let's see the steps involved in the particular crashing of the project. Here, the overall particular crashing of the project is carried out with the help of the critical path method in which we all the earliest starting times are assumed for the determining the project duration as well as critical path. The first step, once we know the overall particular project, we have to determine the particular, or you can say you have to go for the construction of the normal network diagram, that is AOA network diagram, with the earliest starting times. With the help of that, we will come to know the critical path in the overall project. And with the help of this critical path, we construct the time scale diagram. This time scale diagram is nothing else, it is a representation of the particular normal network diagram in the time scale with the scale I can say. Second step, find out the crash cost per unit time, that is nothing else cost loop of each activity in the network diagram, which can be calculated or which can be determined with the help of this formula, that is cost loop is equal to crash cost minus normal cost, normal duration, minus crash duration. Step three, once we get the cost loop of each activity, the step three says that you select such a activity which is having the least cost loop per unit duration or you can say per unit time. Producing the duration of activity means we are assigning some extra resource to the particular activity. So as we are assigning the extra resource, there will be extra expenditure of the money. But keep in mind, the particular activity can be crashed up till the crash time only. Below that, we cannot crash it. So even though we have more money or amount or some resource, we cannot reduce the activity duration below the crash time. Now, step number four. Once we come to know the particular crashing, we go for the number of steps, we select the activity, we go for the crashing. Again, we see the what is the total indirect cost, what is the direct cost and with the help of this both, we go for the defining the total project cost. We try to crash the particular project till the level where the particular optimum duration and optimum cost has been reached. Now crashing of the activity when it is done, they may also, there may be a arrive of new critical path or new critical activities. Okay, finally, we will reach to the stage where we will get the optimum cost as well as optimum duration. And as I said, a time scale diagram is nothing else. It is a scalar representation of the normal network diagram. And the longest path, which is involved in the network diagram is selected as a baseline for the time scale diagram. This is the MCQs. Select the correct answer for this particular. And so you have selected this answers as shown in this particular slide. And these are the references for today's session. Thank you.