Nce603 mod unit2
- 1. Network Techniques: Bar Chart, Mile stone chart, work break down Structure and preparation of networks. Network techniques like PERT and CPM. In construction Management, Project Monitoring and resource allocations through network techniques. 1
- 2. BY MODASSAR ANSARI 3RD Year Department of civil Engineering SUBJECT- Construction Technology And Management SUBJECT CODE-NCE 603 2
- 3. Gives Pictorial Representation of Activities. Activities begin at EST and show their EFT, FF, TF, Durations, etc. Arrows at the relative ends to show dependency. Status Line Concept Unable to show complete interdependency between Activities. Time-scaled Network Diagrams show complete interdependency between Activities. 3
- 4. A work breakdown structure (WBS), in project management and systems engineering, is a deliverable- oriented decomposition of a project into smaller components Dividing complex projects to simpler and manageable tasks is the process identified as Work Breakdown Structure (WBS). Usually, the project managers use this method for simplifying the project execution. In WBS, much larger tasks are broken down to manageable chunks of work. 4
- 5. Accurate and readable project organization. Accurate assignment of responsibilities to the project team. Indicates the project milestones and control points. Helps to estimate the cost, time and risk. Illustrate the project scope, so the stakeholders can have a better understanding of the same. 5
- 6. The preceding sections have dealt comprehensively with the critical path method. As a review, these are the steps to follow in determining a schedule: Complete the CPM network diagram. Label each activity with its proper description. Check network logic. Estimate activity durations. Identify each event with a unique node number 6
- 7. Determine the early event times by implementing the forward pass computations. Determine the late event times by implementing the backward pass computations. Compute total, free, and independent float, and identify the critical activities on the network. Calculate calendar dates for event and activity times. If project duration is not suitable, either revise the network or reschedule the start/completions of the event & activities, and once again go through Steps 5-8. 7
- 8. If the project duration, starts, and finishes of activities are suitable, arrange the activities in the desired sequence, and tabulate activity identification, description, duration, early and late starts, early and late finishes, and floats. Finally, identify the critical activities. 8
- 9. Includes processes required to ensure that the project is completed within the approved budget. Processes involved are: A. Resource Planning B. Cost Estimating C. Cost Budgeting D. Cost Control 9
- 10. Involves determining what physical resources (people, equipment, materials etc) and what quantities of each should be used to perform project activities. 10
- 11. 1. Work Breakdown Structure: A deliverable-oriented grouping of project elements that organizes and defines the total scope of the project. It Identifies the project elements that will need resources. 2. Historical Information 3. Scope Statement: Contains the project justification and the project objectives. 11
- 12. Work Breakdown Structure Resource Requirement Resource Rates: scheduled or non-scheduled Activity Duration Estimates Historical Information Chart of Accounts 12
- 13. Analogous Estimating / Top-down Estimating: Using the actual cost of a previous, similar project as the basis for estimating the cost of the current project. It is less costly but less accurate. (Rough-cost Estimate) Parametric Modeling: Using project characteristics (parameters) in a mathematical model to predict project costs. 13
- 14. Cost Baseline A time-phased budget that will be used to measure and monitor cost performance on the project. It is developed by summing estimated costs by period and is usually displayed in the form of an S-curve. 14
- 15. Cost Control is concerned with (a) Influencing the factors which create changes to the cost baseline to ensure that changes are beneficial. (b) Determining that the cost baseline has changed (c) Managing the actual changes when and as they occur 15
- 16. An element of work performed during the course of a project. An amount of work that can be identified so that we know what it involves and can recognize, when it starts and finishes. An activity normally has an expected duration, an expected cost, and expected resource requirements 16
- 17. In the process of planning alternatives are examined and the best alternative is chosen. The goal of planning is to minimize resource use (cost) while satisfactorily completing the task . Efficient use of equipments , material , labor and ensuring coordinated effort are the basic aim . The outcome of planning is predetermined course of action. Thus, the planning creates an orderly sequence of events, defines strategies to be followed in carrying forth the plan and describes ultimate disposition of the result. Putting the various activity of the project in the sequence on the time frame is the process of scheduling . Scheduling is required for continuous checking of the project (control), for resource mobilization , to minimize the cost and use of resources optimally. 17
- 18. Various scheduling techniques have been employed to plan the activity in sequence in project management . In construction project , bar chart and critical path method (CPM) have been widely used . During the planning process , a manager builds the facilities on paper , thus identities each of the various tasks and time .During construction , these predetermined course of action form the basis for monitoring and the checking the progress of the work . Following steps are followed during planning , scheduling and control . 18
- 19. Identifying and defining activity Defining activity interdependence Estimate time and resources for each activity Constructing the network, Calculations on network for project time earliest start and finish of activity, resource requirement, etc, Project control and project review . 19
- 20. In the network, it is important to know the criticality of the activity, time available to perform the activity provided date of completion of a project. In the previous section we have already talked about various method of obtaining activity duration. We shall be interested in the question that How early we can start the activity. How much we can delay the activity such that target date of completion of project is not affected What the time available to perform the activity. 20
- 21. Early start time Early finish time Latest start time Latest finish time 21
- 22. It is the earliest time by which an activity can started. Let tij be the activity between events i and j. Let T E i is the earliest expected time of the event i then Earliest start time is equal is to EST = T E i 22
- 23. The earliest finish time of an activity is the time by which an activity can be finished earliest. The earliest finish time of an activity is earliest start time plus activity duration. EFT = EST + activity duration 23
- 24. The latest finish time is the time by which an activity must be finished such that completion of the project is not delayed the latest finish time of an activity between events i and j is the latest allowable event time of LFT= T L j 24
- 25. The latest start time is the time by which an activity must start such that completion of project is not delayed. The latest start time of an activity between events i and j is latest finish time minus activity duration. LST = LFT – activity duration 25
- 26. In the last reading we have discuss that in the project with art interested in time available to execute particular task(activity) during the project period. We shall introduce the concept float which tells us how much an activity can fluctuate without affecting the completion of a project. We shall introduce following float Total float. Free float. Independent float. Interfering float. 26
- 27. Total float is the maximum time available during which an activity can fluctuate. It is maximum time available minus activity duration. The maximum time available in the difference between latest finish time minus earliest start time. Maximum time available to execute the work = LFT – EST total float = maximum time avalable – activity duration = LFT – EST - t ij = LST – EST 27
- 28. Free float is the time available to fluctuate the activity without the affecting the succeeding activity. The mean of without affecting succeeding activity is that the activity must finish before the earliest occurrence of the head event. Time available = T E i – EST Free float = Time available – activity duration = T E i – EST - T E ij Free float = T E i – EFT 28
- 29. It is the time available to fluctuate if the preceding activities get completed as late as possible and succeeding activities get started as early as possible. Hence time available = Te i – TL i Independent float =Minimum time available – activity duration = T E i – T L i - T E ij 29
- 30. Interfering float is defined as difference between total float and free float. I.F=T.F-F.F 30
- 31. Find critical path 31 3 2 7 4 1 86 5 8-10-12 3-7-9 8-10-12 4-6-8 3-5-6 7-10-15 5-8-12
- 32. Path A 1-2-7-8 Path B 1-2-6-8 Path C 1-3-6-8 Path D 1-4-5-6-8 32 Path Optimistic time Most likely time Pessimistic time Path A 1-2-7-8 19 26 35 Path B 1-2-6-8 17 26 40 Path C 1-3-6-8 18 27 36 Path D 1-4-5-6-8 19 28 39
- 33. Expected time for each activity 33 6 4 PLo E ttt t
- 34. PATH ACTIVITY to tL tP tE ∑tE A 1-2 6 8 11 8.17 26.342-7 8 10 12 10 7-8 5 8 12 8.17 B 1-2 6 8 11 8.17 26.832-6 4 8 14 8.33 6-8 7 10 15 10.33 C 1-3 3 7 9 6.67 273-6 8 10 12 10 6-8 7 10 15 10.33 D 1-4 5 7 10 7.17 28.33 4-5 4 6 8 6 5-6 3 5 6 4.83 6-8 7 10 15 10.33 Path ‘D’ is critical path 34