Introduction - Construction Project Scheduling and Control - page 9

to coordinating logical relationships, such as when a subcontractor's activity
depends on the completion of another subcontractor's activity. For example,
the drywall contractor cannot start until the framing has been done; once the
drywall is installed, the painter can start painting; and so on.
4. Predict and calculate the cash flow : The timing of an activity has an impact on
the cash flow, which may be an important factor for the contractor (or the
owner) to consider. The contractor (or the owner) must know his or her total
spending in any month or time period. He or she may delay the start of certain
activities within the available float (this term is explained subsequently) to make
sure that the cash flow does not exceed a certain cap.
5. Improve work efficiency : By properly distributing workers and equipment and
having efficient materials management (which is explained in Chapter 6), the
GC can save time and money.
6. Serve as an effective project control tool : Project control must have a solid and
sound baseline with which current performance can be compared. Project con-
trol is achieved by comparing the actual schedule and budget with the baseline
(as planned) schedule and budget (this subject is explained in Chapter 7).
7. Evaluate the effect of changes : Change orders (CO) 3 are usually inevitable, but
well-planned projects may have few or minor ones. Change orders may come
in the form of a directive, that is, an order to the contractor to make a change,
or a request for evaluation before authorization. This change may be an addi-
tion, a deletion, or a substitution. Change orders may have an impact on the
budget, schedule, or both. Cost estimators estimate the cost of change orders
(including the impact on the overhead cost as a result of the schedule change),
but schedulers calculate the impact of the change on the project schedule. It
is the contractor's responsibility to inform the owner of such an impact on the
budget or schedule and obtain the owner's approval.
8. Prove delay claims : Construction delay claims are common. Contractors must
be able to accurately prove their claims against owners (or other parties) using
project schedules. In most cases, only a critical path method (CPM) schedule
can prove or disprove a delay claim, which can be a multimillion dollar one.
Project owners and developers need project scheduling to:
1. Get an idea of a project's expected finish date : Before an owner demands that the
GC complete the project by a certain date, the owner needs to make sure that
it is a feasible and reasonable date. This date is calculated by a CPM schedule,
prepared by the owner or the designer, or a consultant hired by the owner.
This date is also important to the owner, even before selecting a contractor, to
conduct feasibility studies and financial planning.
3 Also called variation orders in other countries, such as the United Kingdom.