Schedule Compression and Time-Cost Trade-Off - Construction Project Scheduling and Control - page 214

1. The contractor's “normal” calculated finish date in the planned schedule does
not meet the imposed finish date in the contract. The contractor usually knows
this situation before starting construction or, sometimes, even before bidding.
In many cases, the owner requires the contractor to submit a construction (crit-
ical path method, or CPM) schedule that shows a satisfactory finish date. Many
government agencies even require the contractor to use a specific scheduling
software program.
2. After starting construction and completing a certain percentage of the project,
the contractor realizes that the project is behind schedule. He or she needs to
accelerate the remainder of the schedule in order to make up for lost time and
to avoid finishing late (referred to as recovery schedule ). In many contracts,
penalties (mostly liquidated damages) may be levied on the contractor for a late
finish. In some cases, this acceleration is requested by the owner even though
the delay was not caused by the contractor. In such case, the owner may be
responsible for the extra cost of the acceleration.
3. In some cases, the contractor may have a contractual monetary incentive to
finish ahead of schedule. The case study mentioned at the beginning of this
chapterisanexample.
4. Sometimes, especially when the economy is doing well, finishing early means,
to the contractor, starting another project earlier and, thus, making more
profit. In many cases, the contractor knows the date when he or she is sup-
posed to mobilize to the next project. This may require the contractor to
compress the current project in order to free certain resources so that they
can be reallocated to the new project.
5. To a certain extent, accelerating a project may prove profitable to the contrac-
tor, as is discussed subsequently.
Acceleration can be planned before the start of a project, as in points 1 and 3
and possibly 4 and 5. In other cases, it is not planned, but at some point during
construction, the work situation necessitates it.
How Can the Duration of a Project Be Shortened?
Construction projects may take more or less time than planned (usually more rather
than less) for reasons that may be within or beyond the contractor's control. Reasons
beyond the contractor's control, such as force majeure , differing site conditions, and
change orders, draw time extensions from the owner in most cases. These situations are
not discussed in this chapter. Instead, our discussion is restricted to the ways in which
the contractor can influence the duration of the project. The Construction Industry
Institute (1988a) has suggested more than 90 techniques for schedule compression.
It further has classified them by project phase or function:
I. Ideas applicable to all phases of a project
II. Engineering phase