International Journal of Engineering Trends and Technology (IJETT) – Volume 18 Number 8 – Dec 2014
Comparative Study of Management Operation System Techniques
(MOST) and CPM in Construction Scheduling
Shailla
RGPM College Bhopal INDIA
ABSTRACT
The CPM was developed in the 1950s by DuPont,
and was first used in missile-defense construction
projects. Since that time, the CPM has been
adapted to other fields including hardware and
software product research and development.
Various computer programs are available to help
project manager’s use the CPM where as The
Management Operation System Technique
(MOST) invented in 1961, replaces PERT and
CPM on construction projects and in program
management. Since its inception, MOST has
gained popularity and is now widely used in both
large and small construction projects. Its use has
been equally effective on projects ranging from
several thousand dollars to $193 million so far. It
is a combination of several traditional and modern
planning techniques like bar chart, Gantt chart,
CPM and PERT.CPM is commonly used with all
forms of projects, including construction,
aerospace and defense, software development,
research
projects,
product
development,
engineering, and plant maintenance, among
others. Any project with interdependent activities
can apply this method of mathematical analysis.
In Most the advantages of these have been
extracted and disadvantages have been
eliminated. Few of the advantages are: it is very
helpful for repetitive works in both real and
infrastructure projects and uses backward
integration which helps in knowing the ground
realities very easily. It gives the project manager
visibility and identifies potential trouble areas
requiring management action. This paper deals
with a comparative study of CPM with MOST for
construction activities of a 25 Kms Road project
and drawing of MOST schedules.
Keywords: (PERT, CPM, MOST, Bar chart,
Gantt chart, MPS)
INTRODUCTION
Critical path method is based on mathematical
calculations and it is used for scheduling project
activities. The critical path method (CPM) is a stepby-step technique for process planning that defines
critical and non-critical tasks with the goal of
preventing time-frame problems and process
bottlenecks. The CPM is ideally suited to projects
consisting of numerous activities that interact in a
complex manner CPM is used for monitoring a
project,
many
superintendents
find
CPM
cumbersome to use, or will simply no find to master
its use. Some will retain their bar charts and transfer
their inputs to the user of the CPM schedule. whereas
MOST not only contributes to single project R & D,
construction, bids, and proposals, but also to MultiProject Scheduling (MPS) either in production short
runs or R & D. MOST's contribution to MPS has
added another management tool to help satisfy the
ever increasing need for better multi-project
scheduling methods For those Large companies that
have been introduced MOST , they elected to try
MOST on a project or two while continuing CPM on
the balance of their projects. After a short while,
these companies realized the dynamic and
economical value in the use of MOST and have
decided to adopt MOST across the value in the use of
MOST and have decided to adopt MOST across the
board. They now use CPM on very few occasions or
on a limited basis.
CAMPARISON BETWEEN MOST Vs CPM
In the illustration a CPM for a house is shown. To
illustrate the conversion to MOST, Figure 8 shows
the basic directions. Note that the float time is shown
by dash lines in front of the job (with CPM analysis,
it is reflected at the back of job) the estimated times
(te) above the bar represents the job. The length of
ISSN: 2231-5381
the bar matches the duration to the calendar, whereas
the length of the job in CPM does not matter (arrow=
job in CPM). The flags in MOST are equivalent to
events in CPM. The logic and language is the same
for CPM and MOST.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 18 Number 8 – Dec 2014
Figure 9 illustrates the MOST conversion from CPM
better graphically with MOST than in CPM for
small one storied building. With the help of a
example.
following example that splitting of jobs is illustrated
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International Journal of Engineering Trends and Technology (IJETT) – Volume 18 Number 8 – Dec 2014
CASE STUDY
Construction Activities of the a road Project considered for a Length of 25 Km using CPM
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International Journal of Engineering Trends and Technology (IJETT) – Volume 18 Number 8 – Dec 2014
earliest occurrence time of event 2.Since duration of
Scheduling the project with CPM: Cpm procedure is
the activity is 4 days, the Es2=TE2=Es1+tE1-2 would be
very efficient
large
carried out for activities #2,#3and #4 and Ecij worked
projects,The time (duration) that each activity will
out accordingly. When we go to next activity #5 , we
take
the
see two activities (#3, #4) are mergeing . here we
activities and, Logical end points such as milestones
would take maximum of Ecij of the both as both must
or deliverable items. Using these values, CPM
be completed before #5 can be started i.e E s5=TE5 =
calculates the longest path of planned activities to
Max.( TE5+0, TE4+0) =10.In the same way, we can
logical end points or to the end of the project, and the
complete rest of the diagram. We find the project
earliest and latest that each activity can start and
would take 45 days to be completed.
The project completion time is 45 days. So its early
finish or late finish must be same, we start from last
activity #28 and take Tl28= 45. This activity has
duration of 3 days .calculating backward we find
to
scheduling procedure for
complete,The dependencies between
finish without making the project longer. Initial time
is supposed to occur as time equal to zero , that is
ES1=TE1=0.We would first start activity #1. Earliest
start time of activities Emanating from event 2 is the
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International Journal of Engineering Trends and Technology (IJETT) – Volume 18 Number 8 – Dec 2014
Construction Activities of the a road Project considered for a Length of 25 Km using MOST
Activity
Duration
(weeks)
Possession of Obstruction Free Site
2
Stump Removal
6
Clearing & Grubbing
7
Taking OGL
3
Submission & Approval of Cross section
5
Excavation
9
Embankment Filling
3
Sub Grade
13
Drainage Layer
14
Wet Mix Macadam (WMM)
15
Dense Graded Bituminous Macadam (DBM)
8
Bituminous Concrete (BC)
4.8
Beginning the scheduling the first few activities . In
this example Activity 1 includes getting clearances
from Forest department and other necessary NOC
from other departments And then clearing grubbing
includes the shifting of pipe line of water and
sewerage if any, and any other building that exists in
the Right of Way. Since the Activity 3 i.e. Clearing
and Grubbing can be started after removal of stumps
that are there after cutting of trees. So the Clearing
and Grubbing can be done with a lag of one week
from the start of Activity 2. It might be seen that the
all the activities are starting after the start of first
activity. If there are any activities which can be
started before the start of the project then it creates a
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dilemma in finalization of critical path.In
construction scheduling with MOST for a
conventional road project proceeds from Possession
of Obstruction Free site to getting the clearances
from all the authorities like forest and environment
ministry, any land acquisition that is to be made,
demolishing of existing buildings coming in the way
of Right of way, and the most important
rehabilitation and resettlement of the Project affected
People. By using the MOST system as described
above the scheduler will develop a realistic schedule.
It will not only show what jobs are necessary to
construct a road to satisfy easy and comfortable
journey, but it will also illustrate the latest start of all
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constraint jobs so as not to jeopardize the schedule or
the contract date. a road construction being done till
the level of Wet Mix Macadam (WMM). In this we
can see the activities having a relationship between
the activities and their constraints. All other jobs will
be shown in their respective schedule positions to
clearly display the relationship of parallel and
overlapping jobs. If the start up of jobs illustrates too
many of the same type of jobs or trades in parallel,
the MOST visibility will highlight this potential
problem.All jobs must be completed on the time
frame against the calendar; there is no room for error.
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There is also no free time to allow for down time or
inclement weather. Since construction is most often
depending upon the weather, it is advisable to allow
for at least two days per month during the winter
months for contingencies or downtime. During the
spring or summer months allow one day per month
for rain. In many instances, some schedulers may
allow two to three weeks per years for inclement
weather. It’s important to allow for these
contingencies when preparing the Baseline Schedule.
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Figure 21 then, shows an update. The update figure
and activities such as laying of top layer and
can be seen the activities 1, 2, 3 and 4 completed and
additional activities. Figure 21 shows a could be kept
rest of the activities in different stages. From this
on baseline schedule we can now commence tracking
figure it can seen whether the activity is on schedule/
progress weekly. A copy of all revisions should be
behind schedule/ahead of schedule. From this we can
kept on file until the project is completed, all
know the criticality of the activity and in turn of the
payments have been received and made, and all
project. It is important to display all the slippages and
required waivers and releases obtained. It’s also
delays completely and honestly to avoid suffering the
recommended the original reproducible vellum be
consequences behind it too late to correct.Now to
stored in the event a similar project is bid at a later
figure 22 and add the remaining jobs which will
date. This schedule will then be of some use if a bid
complete the MOST schedule for this road project
schedule is required.
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CONCLUSION
CPM encourages a logical discipline in the planning,
scheduling, and control of projects.CPM encourages
more long-range and detailed planning of projects.
All project personnel get a complete overview of the
total project.
it provides a standard method of documenting and
communicating project plans, schedules, and time
and cost performances.
It identifies the most critical elements in the plan,
focusing management’s attention to the 10 to 20% of
the project that is most constraining on the
scheduling. Provides an easy method for evaluating
the effects of technical and procedural changes that
occur on the overall project schedule.
It enables the most economical planning of all
operations to meet desirable project completion dates.
An important point to remember is that CPM is an
open-ended process that permits different degrees of
involvement by management to suit their various
needs and objectives. In other words, you can use
CPM at whatever level of detail you feel is necessary.
However, one must always remember that you only
get out of it what you put into it. It will be the
responsibility of the user to choose the best
technique. They are all good, and they can all be used
effectively in the management of construction
projects; just pick the one best liked and use it.
Where as in The Management Operation System
Technique (MOST) It is very helpful for repetitive
works in both real and infrastructure projects. The
use of percentage completion makes the monitoring
of progress very easy.
MOST uses backward integration which helps in
knowing the ground realities very easily. he
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redrawing without rescheduling of activities is done
in a simple manner. It is easy to update and is useful
in cases of arbitration.
The monitoring task by weekly updating is very easy.
No forward and backward pass are required since
MOST diagram describes it in detail.
In-numerous baselines can be used for monitoring,
which is very helpful in tracking of progress with
tight control. Elements of many traditional and new
planning techniques have been incorporated in
MOST. MOST's contributes to MPS as an added
management tool. It identifies potential trouble areas
requiring management action.
REFERENCES
1.
Anthony L. Lannone, Andrew M. Civitello, Jr.Prentice-Hall, 1989. Construction Scheduling
Simplified.
2.
Project planning and control with PERT & CPM
Dr. B.C.Punammia
3.
www.springer.cou/cda/content
4.
www.mindtoul.com
5.
www.edu.twfurang/cho5.ppt
6.
www.theconstructor.org
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