Presentation on theme: "CONSTRUCTION SCHEDULING & COST CONTROL"— Presentation transcript:
1CONSTRUCTION SCHEDULING & COST CONTROL ByPROF. LIAQAT ALI QURESHIUET TAXILA
2Planning & Scheduling Planning: Process of choosing the method and order of workScheduling:Process of determining the interrelationship of associated timings of operations.
3Steps in Construction Scheduling Splitting of the project into work activitiesDetermining logic relationships/interrelationships between activities.Construction of Network Diagrams.Assigning durations to work activities.CPM Calculations resulting in start times, finish times and float calculations of activities.Marking of critical PathConstruction of Bar Charts / Time phased diagrams.
4ActivityAn element of work performed during the course of a project. OrAn 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
5Network DiagramsAny schematic display of the logical relationship of project activities.Always drawn from left to right to reflect project chronology.Usually a combination of arrows and nodes.Mainly of two types:1. Arrow Diagram2. Node Diagram / Precedence Diagram
6Arrow DiagramsActivities shown by Arrows. Relationship between activities shown by nodes / events.Length of arrows does not obey any scale.Start-to-finish relationships.Dummies.Numbering of nodes / events.Milestones
9Activity DurationsActivity duration is forecasted by any of the several means, including:(1) Check Past Records.(2) Check Standards and / or cost guides, if available.(3) Ask the workers, who will do it(4) make an educated guessAny time units may be allotted to activity durations like days, hours, weeks, months, shifts, etc.In CPM, a single duration is forecasted for an activity.In PERT (Program Evaluation & Review Techniques), 3 durations are forecasted for an activity and mean taken by weighted average method. Then, Project’s Duration or any Event Completion Time is calculated by probability distribution.
10CPM Calculations Calculates the following for each activity EST = Earliest Starting TimeEFT = Earliest Finishing TimeLST = Latest Starting TimeLFT = Latest Finishing TimeTF = Total FloatFF = Free FloatTotal Float is Maximum time for which an activity can be delayed without delaying the project.Free Float is maximum time for which an activity cane be delayed without delaying the start of proceeding activity.Total Float = Free Float + Interfering Float
11Critical PathThe path (or paths) in the network diagram, from start to finish, on which all the activities have zero total and free floats, is called Critical Path.It is the longest path (or paths) from start to finish in a net work diagram.It gives minimum normal time to complete a project.It is usually marked by double lined arrows in a network diagram.
12SINGLE SPAN BRIDGE PROJECT (ACTIVITY DESCRIPTION)Activity CodeOperationDependenceEst. Dur.(Days)ENAEarthworks, north abutment-5ESAEarthworks, south abutment4CONNConstruction, north abutment14CONSConstruction, south abutmentESA, CONN12COMNCompaction, north abutment2CIMSCompaction, south abutmentCONS, COMNRNBRoad, north of bridgeRSBRoad, south of bridgeRNB,COMSPBPrefabricate bridge deck18TDTransport deck to siteEBErect bridge deckTD, CONN, CONS, COMN3LBSLay bridge surfaceEB, RNB, RSBICBInstall crash barriers etc.1LLandscapeRNB, RSB
15Node DiagramsActivities shown by Nodes, relationship between Activities shown by arrows or links.Easier to construct.Generally no need of dummies. Instead dummies used only to give single start or finish.CPM Calculations similar to Arrow diagrams.
19Bar Chart 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 ConceptUnable to show complete interdependency between Activities.Time-scaled Network Diagrams show complete interdependency between Activities.
23COST MANAGEMENTIncludes processes required to ensure that the project is completed within the approved budget.Processes involved are:1- Resource Planning2- Cost Estimating3- Cost Budgeting4- Cost Control
241- Resource PlanningInvolves determining what physical resources (people, equipment, materials etc) and what quantities of each should be used to perform project activities.
25Inputs to Resource Planning 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 Information3. Scope Statement:Contains the project justification and the project objectives.
26Inputs to Resource Planning 4. Resource Pool Description:Knowledge of what resources are potentially available.5. Organizational Policies:The policies of the performing organization regarding staffing and the rental or purchase of supplies and equipment.
27Tools and Techniques to Resource Planning Expert JudgmentAlternative identifications:To adopt different approaches for the same problem.
28Outputs from Resource Planning Resource Requirements:Description of what types of resources are required and in what quantities for each element of the work break down structure.
29Cost EstimatingDeveloping an approximation (estimates) of the costs of the resources needed to complete project activities.Includes identifying and considering various costing alternatives.
30Cost Estimating and Pricing Cost Estimating involves developing an assessment of the likely quantitative result-how much will it cost the performing organization to provide the product or service involved.Pricing is a business decision-how much will the performing organization charge for the product or service
31Inputs to Cost Estimating Work Breakdown StructureResource RequirementResource Rates:scheduled or non-scheduledActivity Duration EstimatesHistorical InformationChart of Accounts:Describes the coding structure used by the performing organization to report financial information in its general ledger
32Tools and Techniques for Cost Estimating 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.
33Tools and Techniques for Cost Estimating Bottom-up Estimating:Estimating the cost of individual work items, then summarizing or rolling up the individual estimates to get a project title. (Detailed Estimate)Computerized Tools:Use of computerized tools such as project management software and spreadsheets to assist with cost estimating.
34Outputs from Cost Estimating Cost EstimatesSupporting Details like Scope of work, Calculation sheet, Assumptions made, Possible range of results, etc.Cost Management Plan describing how cost variances will be managed.
35Cost BudgetingAllocation of overall cost estimates to individual work items in order to establish a cost baseline for measuring project performances.
36Inputs to Cost Budgeting Cost EstimatesWork Breakdown StructureProject Schedule
37Tools and Techniques for Cost Budgeting Tools and Techniques for developing project Cost Estimates are used to develop budgets for work items as well
38Outputs from Cost Budgeting Cost BaselineA 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.
40Cost Control 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
41Cost Control Cost Control includes: Monitoring cost performances to detect variances from plan.Ensuring that all appropriate changes are recorded accurately in the cost baselinePreventing incorrect, inappropriate, or unauthorized changes from being included in the cost baseline.Informing appropriate stakeholders of authorized changes.
42Inputs to Cost Control Cost Baseline Performance Reports Provide information about cost performance such as which budgets have been met and which have not. It also alerts the project team to issues which may cause problems in the future.
43Inputs to Cost Control Change Requests These may occur in many forms-oral or written, direct or indirect, externally or internally initiated, and legally mandated or optional. These may require increasing the budget or may allow decreasing it.
44Tools and Techniques for Cost Control Cost Change Control SystemIt defines the procedures by which the cost baseline may be changed. It includes the paperwork, tracking systems, and approval levels necessary for authorizing changes.Performance MeasurementIt helps to assess the magnitude of any variations which do occur.
45Tools and Techniques for Cost Control Additional PlanningPerspective changes may require new or revised cost estimates or analysis of alternate approaches.Computerized Tools
46Outputs from Cost Control Revised Cost EstimatesBudget UpdatesCorrective ActionEstimate at CompletionIt is a forecast of total project costs based on project performance.Lessons Learned
47OBJECTS OF COST CONTROL 1 – To have a knowledge of the profit and loss of the project throughout the duration of the project.PROJECT PROFITSClient payments.Sale of surplus or scrap material and plantPayments for plants or labor by others, where, this plant or labor is , from time to time not required for the project.PROJECT LOSSESLabor and site office costsPlant costsSite overheads i.e. site facilities, access roads and office etcCost of tendering including bonds, insurance, etc.Material costs.Head office overheads proportioned over all current projects.
48OBJECTS OF COST CONTROL 2 – To have a comparison between the actual project performance and that conceived in the original project plan.Comparison is basically done according to the following bases:According to units of productionAccording to line items; e.g., labour, material, equipment, overheads, ---3 – Provides feedback data on actual project performance to future project planning