Project Scheduling 2
Prepared by Sebghatullah Karimi
(Junior Lecturer of Kabul Polytechnic University)
Civil Engineering Faculty
Explain how the work environment, the
construction contract, and the project scope
influence the scheduling process.
Explain the three types of project activities used
Describe the characteristics of a network diagram.
Work breakdown structure – The organization of the
project into specific parts that can be coordinated and
Activity – A well-defined, measurable part of the
overall project. An activity must be suitable for
assignment to a particular project team member, and
it consumes both time and resources.
Trade – A construction specialty, such as plumber,
Submittal – A sample of an item to be procured for a
project by a supplier or subcontractor. A submittal
must be approved by the owner or designer prior to
• A network schedule is graphical drawing of a logical sequence of
events to complete a project. A network-based schedule is a
powerful tool for the planning, development, and construction of
• The development of a network-based schedule follows a logical
process that should involve most of the key project team members.
Every network schedule must begin with a complete understanding
of the project objective, as defined by the owner. The project
participants then take this objective and break it down into tasks
that provide the level of detail necessary to organize, manage, and
control the project. Once these tasks are defined, the project team
establishes the order in which the tasks are to be performed, such
that the project will be completed in an efficient manner.
• To create the network, team members decide which activities must
precede, succeed, or run concurrently with other activities. The end
result of this process is a logic diagram that accurately depicts the
order that the work will follow.
The preparation of a network schedule requires a careful analysis of
The work environment. The work environment includes such
consideration as the weather, site conditions, availability of building
materials, access for deliveries, availability of power, and the
amount of construction currently occurring in the region.
The contract. A construction contract will typically include the
project completion date, milestones, incentive clauses (which
provide bonuses for early completion), liquidated damages clauses
(which provide penalties for late completion), work rules governing
safety and hiring requirements, and identification of materials and
work that will be provided by the owner. All of these considerations
will affect project organization and scheduling.
The project scope. The scope of the project, as described in the
drawings and specifications, is a major consideration in scheduling.
Drawings and specifications are the source of all the materials and
quantities used in the project and may also describe required
1. The first step in the networking process is to define
the work breakdown structure for the project.
2. From the work breakdown structure, the team
defines the specific activities that will make up the
network diagram. An activity must be suitable for
assignment to a particular project team member,
and it should consume both time and resources.
Construction activities can generally be characterized as one of three
Production activities are the activities that define the actual
physical construction of the project. Examples include Erect
Concrete Wall. A well-developed schedule allows the project team
to separate all activities of each trade in such a way that each
contractor has a clearly defined scope of work without overlap or
Procurement activities involve the purchase of materials,
equipment, and services for the project. Most procurement
activities follow a logical sequence, beginning with the preparation
of a submittal, the approval of the submittal by the owner or
designer, the ordering and fabrication of the item, and then the
delivery of the item to the job site..
Administrative activities include required inspections by local
officials or regulatory agencies, as well as permitting. Identifying
these activities requires the involvement of all project team
members, since normally no one person knows all the
administrative requirements for a complex project. 7
A key event in a project schedule can be identified by the use of a
milestone. Examples of milestones include the planned shutdown
of electricity or water supply in order to make connections to
existing utilities, the delivery of a certain phase of a project to the
owner, or a city agreement that a road be opened by a specific
date. Unlike an activity, a milestone cannot be assigned to a
company or person and does not consume time or resources. A
milestone is used simply to signify an important point in the life of
A network diagram is a pictorial representation of all
activities that make up a project and the order in
which these activities must occur to complete the
project in an efficient manner. In order to
develop the network diagram, the scheduler must
answer the following questions for each activity:
What activities must occur before this activity
can be done?
What activities must follow this activity?
What activities can be accomplished at the
same time that this activity is occurring?
A typical example of a network diagram is shown at the top of
Figure 9.4 in the Gould textbook. As you can see:
The diagram is read from left to right.
Activities are identified by rectangles (nodes) and connected
Each rectangle indicates a single activity.
The network is continuous. Each activity, except the first and
last, has both preceding and succeeding activities.
Activities without predecessors are assumed to begin at the
start of the project.
Activities without successors are assumed to be complete
when the project finishes.
No activity can start until all preceding activities have been