3. Steps in Construction Scheduling
Splitting of the project into work activities
Determining logic relationships/interrelationships
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 Path
Construction of Bar Charts / Time phased
An element of work performed during the
course of a project. Or
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
5. Network Diagrams
Any schematic display of the logical relationship
of project activities.
Always drawn from left to right to reflect project
Usually a combination of arrows and nodes.
Mainly of two types:
1. Arrow Diagram
2. Node Diagram / Precedence Diagram
6. Arrow Diagrams
Activities shown by Arrows. Relationship
between activities shown by nodes / events.
Length of arrows does not obey any scale.
Numbering of nodes / events.
9. Activity Durations
Activity 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 guess
Any 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
10. CPM Calculations
Calculates the following for each activity
EST = Earliest Starting Time
EFT = Earliest Finishing Time
LST = Latest Starting Time
LFT = Latest Finishing Time
TF = Total Float
FF = Free Float
Total 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
11. Critical Path
The path (or paths) in the network diagram,
from start to finish, on which all the activities
have zero total and free floats, is called
It is the longest path (or paths) from start to
finish in a net work diagram.
It gives minimum normal time to complete a
It is usually marked by double lined arrows in
a network diagram.
12. SINGLE SPAN BRIDGE PROJECT
Activity Code Operation Dependence Est. Dur.
ENA Earthworks, north abutment - 5
ESA Earthworks, south abutment ENA 4
CONN Construction, north abutment ENA 14
CONS Construction, south abutment ESA, CONN 12
COMN Compaction, north abutment CONN 2
CIMS Compaction, south abutment CONS, COMN 2
RNB Road, north of bridge COMN 2
RSB Road, south of bridge RNB,COMS 2
PB Prefabricate bridge deck - 18
TD Transport deck to site PB 2
EB Erect bridge deck TD, CONN,
LBS Lay bridge surface EB, RNB, RSB 2
ICB Install crash barriers etc. EB 1
L Landscape RNB, RSB 1
15. Node Diagrams
Activities 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
CPM Calculations similar to Arrow diagrams.
19. Bar 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 Concept
Unable to show complete interdependency
Time-scaled Network Diagrams show complete
interdependency between Activities.
23. COST MANAGEMENT
Includes processes required to ensure that
the project is completed within the approved
Processes involved are:
1- Resource Planning
2- Cost Estimating
3- Cost Budgeting
4- Cost Control
24. 1- Resource Planning
Involves determining what physical resources
(people, equipment, materials etc) and what
quantities of each should be used to perform
25. Inputs 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 Information
3. Scope Statement:
Contains the project justification and the
26. Inputs to Resource Planning
4. Resource Pool Description:
Knowledge of what resources are
5. Organizational Policies:
The policies of the performing organization
regarding staffing and the rental or
purchase of supplies and equipment.
27. Tools and Techniques to Resource Planning
1. Expert Judgment
2. Alternative identifications:
To adopt different approaches for
the same problem.
28. Outputs from Resource Planning
1. Resource Requirements:
Description of what types of resources
are required and in what quantities for
each element of the work break down
29. Cost Estimating
Developing an approximation (estimates) of
the costs of the resources needed to
complete project activities.
Includes identifying and considering various
30. Cost 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
31. Inputs to Cost Estimating
Work Breakdown Structure
scheduled or non-scheduled
Activity Duration Estimates
Chart of Accounts:
Describes the coding structure used by the performing
organization to report financial information in its general
32. Tools 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)
Using project characteristics (parameters) in
a mathematical model to predict project
33. Tools and Techniques for Cost Estimating
Estimating the cost of individual work
items, then summarizing or rolling up the
individual estimates to get a project title.
Use of computerized tools such as
project management software and
spreadsheets to assist with cost estimating.
34. Outputs from Cost Estimating
Supporting Details like Scope of work,
Calculation sheet, Assumptions made,
Possible range of results, etc.
Cost Management Plan describing how cost
variances will be managed.
35. Cost Budgeting
Allocation of overall cost estimates to
individual work items in order to establish a
cost baseline for measuring project
36. Inputs to Cost Budgeting
Work Breakdown Structure
37. Tools and Techniques for Cost Budgeting
Tools and Techniques for developing project
Cost Estimates are used to develop budgets
for work items as well
38. Outputs from Cost Budgeting
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-
40. Cost 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
(c) Managing the actual changes when and
as they occur
41. Cost Control
Cost Control includes:
Monitoring cost performances to detect
variances from plan.
Ensuring that all appropriate changes are
recorded accurately in the cost baseline
Preventing incorrect, inappropriate, or
unauthorized changes from being included in the
Informing appropriate stakeholders of authorized
42. Inputs to Cost Control
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
43. Inputs to Cost Control
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.
44. Tools and Techniques for Cost Control
Cost Change Control System
It defines the procedures by which the cost
baseline may be changed. It includes the
paperwork, tracking systems, and approval
levels necessary for authorizing changes.
It helps to assess the magnitude of any
variations which do occur.
45. Tools and Techniques for Cost Control
Perspective changes may require new or
revised cost estimates or analysis of
46. Outputs from Cost Control
Revised Cost Estimates
Estimate at Completion
It is a forecast of total project costs based
on project performance.
47. OBJECTS OF COST CONTROL
1 – To have a knowledge of the profit and loss of the
project throughout the duration of the project.
1) Client payments.
2) Sale of surplus or scrap material and plant
3) Payments for plants or labor by others, where, this plant or labor is ,
from time to time not required for the project.
1) Labor and site office costs
2) Plant costs
3) Site overheads i.e. site facilities, access roads and office etc
4) Cost of tendering including bonds, insurance, etc.
5) Material costs.
6) Head office overheads proportioned over all current projects.
48. OBJECTS 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
1) According to units of production
2) According to line items; e.g., labour, material,
equipment, overheads, ---
3 – Provides feedback data on actual project
performance to future project planning