Resource Allocation and Resource Leveling - Construction Project Scheduling and Control - page 129

Wednesday through Saturday only, the program will automatically schedule
work only during those days for the activities to which this crew has been
assigned.
6. Resource-driven schedules are possible. Under certain conditions, you can
allow your resources to control the duration of an activity. For example, if a
resource-driven activity requires four painters for 10 days, the program uses
a total of 40 man-days, or 320 man-hours, for its basis. Depending on the
painters' availability and logic among activities, the scheduling program may
assign a fluctuating number of painters to the activity to finish the job in themost
efficient way (from a resource management perspective). The result may be an
increase or a decrease in the duration, with the same budget of 320 man-hours.
This option may also be turned off to maintain the original duration.

One interesting scenario that pertains to point 4 occurs when resources are priced
through a certain date and then increase. Suppose that a union contract calls for a
carpenter's pay rate of $34 per hour through 30 June 2014. After this, it will increase
to $36.50 per hour. Assume that a particular activity requires 128 carpenter man-hours
and is scheduled to take place in June 2014. The total cost for the carpenters is 128 ∗
$34 = $4

352. Now, suppose that the activity schedule slips to July. The cost will
increase by 128 ∗ $2

,

50 = $320, for a new budget of $4,672. You have to be careful
in such cases as to whether to allow the resource dictionary to drive the budget or to
treat the budget as a fixed amount.

.

Leveling Resources in a Project

Resource leveling is a mathematically complex process. The resource-leveling method
is called the minimum moment algorithm , as discussed by Robert B. Harris (1978)
in his classic textbook, Precedence and Arrow Networking Techniques for Construction,
and other references. Fortunately, computer programs have eliminated the difficult
part of this process. Let us deal with resource leveling manually for a simple example.

Example 6.2

A subcontractor needs to install flooring in two areas:

1. Area 1 : This area has old vinyl tile that must be removed and replaced
with new vinyl tile.
2. Area 2 : This area has a concrete slab that needs to be topped with
ceramic tile.

This simple project is broken into the activities shown in the following
table, along with the logic, the duration, and the required number of laborers
for each activity.