|
Keeping the Project on Schedule
The management of a construction project requires a multitude of abilities,
duties, and responsibilities of the Resident Engineer (R/E). Some of these
responsibilities consist of, to name a few, contract administration; analyzing
and issuing change orders; inspection; and coordination between the VAMC and
contractor. Contract administration includes the oversight of the project
through the eyes of a cost and manpower loaded CPM which is of particular
importance and the focus of this article.
Manpower and cash flow are two of the key elements of the schedule, both of
which must be regularly monitored to give the resident engineer and contractor
early warning signs on how the project is progressing and raise a red flag when
the project is starting to "head south." By monitoring these two elements in
the project schedule as well as the accuracy of the schedule's construction logic,
the R/E maximizes the opportunity to keep the project on schedule.
Even in a closely monitored project, however, there are many reasons for a
project falling behind schedule. The following are major causes of project
schedule slippage:
- Changed work
- Faulty logic
- Insufficient manpower
- Contractor's failure to work on critical path activities
- Unrealistic activity durations
Delays due to changed work
Assuming that the contractor is reasonably following the approved schedule and
working on the critical path activities, the project may fall behind schedule
from month-to-month. One reason for the slippage may be change order work
affecting the critical path; this slippage would show up on the monthly analysis
of the parallel runs implementing the change orders into the logic and analyzing
the schedule to determine potential reasons for slippages. If change orders are
causing the project slippage, a time extension is warranted and should be issued
adjusting the contract completion date to reflect the affect of the change on the
contractor's schedule.
Faulty Schedule Logic
After each monthly update it is imperative to re-evaluate the schedule logic and
adjust the logic if necessary as part of the update process. All too often the
update is performed mechanically with no consideration given to re-evaluating the
plan for the balance of the project. To update a CPM schedule whose foundation
(logic and/or estimated durations) is outdated will typically result in a misleading
forecast and erroneous reports.
Insufficient manpower
Based upon manpower data initially obtained from the contractor in the Day-1 CPM,
the project scheduling software, Primavera (P3), can give the resident engineer
and contractor the ability to generate reports identifying manpower requirements
for individual trades. These reports could include a two-month projection (window)
of manpower requirement by trade/work area or a projection of manpower by trade for
the upcoming month. (Exhibit)
Project slippage can often be attributed to a lack of manpower or insufficient
manpower on critical path activities. The easiest way to verify the adequacy of
the contractor's projected manpower is to compare the actual manpower indicated on
the daily logs with the manpower report generated from the previously updated schedule.
If the project is continuously slipping from month-to-month, the cause may be a lack of
manpower. An example of insufficient manpower is as follows: The critical path
generated from the updated information indicates the critical path going through
Rough-In Power Conduit Area 1 - 15 days, Rough-in Power Conduit Area 2 - 15 days,
Pull Power Wire Area 2 - 10 Days, etc. Reviewing either the approved CPM diagram
or a manpower report indicates that the contractor planned on performing the conduit
Rough-In work with 4 electricians and the estimated duration in the schedule is 15
workdays. Based upon the resident engineers experience, the contractor's projection
of 15 workdays utilizing 4 electricians is a reasonable duration based on the amount
of power conduit in Area 1. A review of the daily logs indicate that over the past
15 work days the contractor only achieved the estimated manpower of 4 electricians
in Area 1 on 3 days. The average number of electricians for the 15-day period was
2, well below the projected 4-man crew. Barring any disruptions due to VA changes,
which may have precluded the contractor from achieving the projected planned manpower,
it is obvious from the above scenario that the project slippage is attributed to
insufficient manpower. Similarly, the progress schedule can reveal portions of
the work where performance is ahead of schedule. In these areas, it is possible
that manpower can be reduced, without delaying the project completion date, and
the surplus manpower may be used in more critical areas of the project.
VA also requires the contractor to submit activity cost data for each activity in
the CPM schedule. A "cost-loaded" CPM provides a method to determine a cash flow
forecast for the project on a month-by-month base. Comparing the actual project
percent complete to the planned percent complete for the same period will give the
resident engineer and contractor an indication as to how the project is progressing.
If the actual cash flow is lagging behind the planned or projected cash flow, chances
are the project is heading for potential problems if it is not having problems already.
Usually, unless there is unrealistic cash flow data in the schedule, the actual percent
complete compared to the as-planned cash flow is a good barometer of how the project is
progressing and whether the project is on schedule.
Contractor's failure to work on critical path activities
What is critical today may not be critical tomorrow. The critical path identified in
the original or Day-1 schedule, will only remain the critical path if everything goes
according to plan. Experienced resident engineers and contractors know that this is
almost never the case. Although CPM is a well accepted and powerful tool for managing
the day-to-day events on a project, the accuracy of the calculated milestones or project
completion date is directly dependent on the completion of every critical task taking no
longer than originally estimate. If the contractor fails to work on the critical path or
works on it part time, the project schedule will slip a day for a day that the contractor
did not work on the critical path. The project slippage will be reflected in the next
month's update. A report that can assist the resident engineer and contractor is the
Hot List Report, which reflects the activities the contractor must be working on during
the reporting period to maintain the projected project completion date. It is a good
practice to review the Hot List Report at the weekly progress meetings and discuss the
status of the work effort on the critical path and near critical activities. The resident
engineer and contractor must monitor the near critical activities as closely as the
critical activities to prevent them from becoming the next month's critical path. A
near critical activity is defined as an activity whose early start and late start dates
fall between the current as-of date and the next scheduled update date. Doing so will
keep both the contractor and the resident engineer focused on the status of the project
and the progress on the critical path.
Unrealistic activity durations
For any given activity in a construction schedule, a delay may occur i.e., late
delivery of material or equipment, which is truly unforeseeable, and the Day-1
duration for the activity may have been entirely appropriate. This is not always
the case; all too often the duration of activities in a CPM network are guesses
that may be unrealistically short, calculated by how much time the contractor has
to complete the project rather than how long the activity will actually take to
complete. Another explanation is that the planned duration is based on an
unrealistic crew size which will never be achieved. Conversely, durations
can be longer than necessary based on a planned smaller crew size where in
actuality the crew size is much larger than originally planned. Comparing a
similar area of work and evaluating its durations, and adjusting the durations
for the next portion of work according to the historical as-built information,
can easily correct this situation and give the resident engineer and contractor
a more realistic schedule.
Conclusion
Updating the schedule monthly is not sufficient to keep the project on schedule
and prevent the project completion date from slipping. The updating process must
include a systematic review of the schedule's logic, durations, manpower, cash
flow and change orders, as well as an analysis of the actual progress of the
work to date.
The above represents an explanation of the various major causes of schedule
slippage. Remember, the CPM schedule is only as good as the information which
is used in its preparation and maintenance, and the ability of the resident
engineer and contractor to identify the necessary activities,
determine their interrelationships, accurately estimate the time necessary to
complete these activities, and translate the information generated by the up
dating process into realistic solutions to problems arising on the project.
|
