Moses Zhou Project

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NATIONAL UNIVERSITY OF SCIENCE ANDTECHNOLOGY

FACULTY OF THE BUILT ENVIRONMENT

Department of quantity surveying

NAME: ZHOU MOSES

STUDENT ID: P007 0869T

PROJECT TITLEAn analysis of implementation of planning and scheduling techniques employed in the

construction industry, a case of Harare and Bulawayo

A dissertation submitted with the Department of Quantity Surveying in partial

fulfilment of the bachelor of Quantity Surveying Honours Degree

June 2011



An analysis of implementation of planning and scheduling techniques employed in the construction industry,

A case of Harare and Bulawayo

MOSES ZHOU iP007 0869T

DECLARATION

I declare that this dissertation is my own work, where other sources were used I provided correct

references.

Signed……………………….

Moses Zhou





MOSES ZHOU iiP007 0869T

DEDICATION

This research is dedicated to my father and mother who have continued to support me through

thick and thin. May the Lord God almighty continue to bless them, Amen.





MOSES ZHOU iiiP007 0869T

ACKNOWLEDGEMENTS

Special thanks go to my supervisor, Ms Mapungwana for her comments and words of advice

and continuous assistance and encouragements as well as my fellow students.

I would also want to give thanks to all the companies and respondents for the time spent on

the questionnaire and timeous returns.

A special mention also goes to my parents for their financial support throughout the project.





MOSES ZHOU ivP007 0869T

ABSTRACT

The main aim of this paper was to investigate the implementation of planning and scheduling

techniques on construction projects in Zimbabwe. The researcher used a sample size of 20 drawn

using stratified random sampling, snowballing was used to complement in the cases when the

selected object fail to respond. The planning and scheduling techniques that are currently under

use in the construction industry were identified. Further to this the level of applicability was

investigated and the benefits and shortcomings of the planning and scheduling techniques were

identified. The research was carried out in Harare and Bulawayo and the construction

stakeholders responded through questionnaires. The construction stakeholders indicated that they

are very much aware of the planning and scheduling techniques and the benefits of using them

but they indicated little knowledge on how the work. The researcher is of the opinion that if planning and scheduling is done in line with the Project Management Institute’s suggested

sequence the projects will be completed on time, within the budget and within all the functional

requirements. According to the results of the hypothesis testing, there is a strong relationship

between planning and scheduling and project success. The researcher therefore recommends

further researchers to focus their efforts on advocating for new and upcoming planning and

scheduling techniques such as Petri nets as indicated by the researcher survey.





MOSES ZHOU vP007 0869T

Table of Contents

DECLARATION ............................................................................................................................. i DEDICATION ................................................................................................................................ ii ACKNOWLEDGEMENTS ........................................................................................................... iii ABSTRACT ................................................................................................................................... iv Table of Contents ............................................................................................................................ v LIST OF FIGURES ..................................................................................................................... viii LIST OF TABLES ......................................................................................................................... ix CHAPTER ONE- INTRODUCTION............................................................................................. 1

1.0 Introduction ........................................................................................................................... 1 1.1 Back ground .......................................................................................................................... 3 1.2 Problem statement ................................................................................................................. 4 1.3 Research questions ................................................................................................................ 5 1.4 The aim of study is: ............................................................................................................... 6 1.5 Objectives .............................................................................................................................. 6 1.6 Justification ........................................................................................................................... 6 1.7 Hypothesis ............................................................................................................................. 7 1.8 Research outline .................................................................................................................... 7

CHAPTER TWO- LITERATURE REVIEW ................................................................................. 9 2.0 Introduction ........................................................................................................................... 9 2.1 Definition of terms ................................................................................................................ 9 2.2 Planning and scheduling techniques ................................................................................... 11

2.2.1 Project Evaluation and Review Technique (PERT) ..................................................... 12 2.2.2 Critical Path Method ..................................................................................................... 16 2.2.3 Gantt chart .................................................................................................................... 17 2.2.4 Work break down structure .......................................................................................... 20 2.2.5 Line of Balance ............................................................................................................. 22 2.2.6 Petri Nets ...................................................................................................................... 23

2.3 Applicability of Planning and scheduling techniques ......................................................... 25





MOSES ZHOU viP007 0869T

2.3.1 Critical Path Method ..................................................................................................... 25 2.3.2 Project Evaluation Review Technique ......................................................................... 27 2.3.3 Gantt chart .................................................................................................................... 27 2.3.4 Work breakdown structure ........................................................................................... 28 2.3.5 Line Of Balance ............................................................................................................ 28 2.3.6 Petri nets ....................................................................................................................... 29

2.4 Challenges to the Planning and Scheduling Process ........................................................... 29 2.4.1 Cost ............................................................................................................................... 29 2.4.2 Time .............................................................................................................................. 30 2,4.3 Human resources and skills .......................................................................................... 30

2.5 Shortcomings and Benefits of Planning and Scheduling Techniques ................................. 30 2.5.1 Shortcomings of Planning and Scheduling ................................................................... 30 2.5.2 Benefits of planning and scheduling ............................................................................ 31

2.6 Conclusion ........................................................................................................................... 32 CHAPTER THREE- RESEARCH METHODOLOGY ............................................................... 33

3.0 Introduction ......................................................................................................................... 33 3.1 Research design ................................................................................................................... 33

3.1.1 Sampling frame............................................................................................................. 33 3.1.2 Sample size ................................................................................................................... 33 3.1.3 Target Population ......................................................................................................... 34 3.1.4 Area of study ................................................................................................................ 34

3.2 Sampling methods ............................................................................................................... 34 3.2.1 Stratified Random Sampling ........................................................................................ 34 3.2.2 Random Sampling ........................................................................................................ 35 3.2.3 Snowball Sampling ....................................................................................................... 36

3.3 Sources of data .................................................................................................................... 36 3.3.1 Secondary sources ........................................................................................................ 36 3.3.2 Primary data sources ..................................................................................................... 37

3.4 Research instruments........................................................................................................... 37 3.4.1 Personal interviews ....................................................................................................... 37 3.4.2 Questionnaire ................................................................................................................ 38





MOSES ZHOU viiP007 0869T

3.5 Avoiding bias ...................................................................................................................... 39 3.6 Limitations and constraints ................................................................................................. 39 3.7 Data presentation and analysis plan .................................................................................... 39 3.8 Conclusion ........................................................................................................................... 39

CHAPTER FOUR- DATA PRESENTATION AND ANALYSIS .............................................. 41 4.0 Introduction ......................................................................................................................... 41 4.1 General information ............................................................................................................ 41 4.2 Planning and scheduling techniques ................................................................................... 43

4.2.1 Planning and scheduling techniques employed ............................................................ 43 4.2.2 Stage of Planning and Scheduling ................................................................................ 44 4.2.3 Frequency of application .............................................................................................. 45 4.2.4 Percentage successful ................................................................................................... 46

4.3 Applicability of planning and scheduling techniques ......................................................... 48 4.3.1 Percentage successful implementation ......................................................................... 48 4.3.2 Relevance of planning and scheduling techniques ....................................................... 49 4.3.3 Factors hindering planning and scheduling .................................................................. 50

4.4 Challenges faced when implementing planning and scheduling techniques ...................... 51 4.4.1 The challenges .............................................................................................................. 51 4.4.2 Stages at which challenges are encountered ................................................................. 53

4.5 Shortcomings and benefits of planning and scheduling ...................................................... 54 4.6 Summary ............................................................................................................................. 56

CHAPTER FIVE- CONCLUSIONS AND RECOMMENDATIONS ......................................... 57 5.0 Introduction ......................................................................................................................... 57 5.1 Conclusion ........................................................................................................................... 57 5.2 Recommendation for further studies ................................................................................... 58

Bibliography ................................................................................................................................. 59 APPENDIX 1: QUESTIONNAIRE ............................................................................................. 61





MOSES ZHOU viiiP007 0869T

LIST OF FIGURES

Chapter 1

Figure 1. 1- Cost-Time-Quality triangle ......................................................................................... 2

Chapter 2

Figure 2. 1- Activity on node network diagram ............................................................................ 12 Figure 2. 2- Beta distribution ........................................................................................................ 14 Figure 2. 3- The Gantt chart .......................................................................................................... 18

Chapter 4

Figure 4. 1- Experience of respondents ........................................................................................ 42 Figure 4. 2- Techniques being used .............................................................................................. 44 Figure 4. 3- Stage of implementation ........................................................................................... 45 Figure 4. 4 –Frequency of application .......................................................................................... 46 Figure 4. 5- Percentage time, cost and quality successful completion ......................................... 47 Figure 4. 6- Percentage applicability ............................................................................................ 49 Figure 4. 7-Relevance of techniques ............................................................................................. 50 Figure 4. 8- Planning and scheduling vs. Success ........................................................................ 56





MOSES ZHOU ixP007 0869T

LIST OF TABLES

Chapter 1

Table 2. 1- Network data .............................................................................................................. 11 Table 2. 2- PERT Network data .................................................................................................... 15

Chapter 3

Table 3. 1- Sampling strata table .................................................................................................. 35

Chapter 4

Table 4. 1-Response rate Table ..................................................................................................... 42 Table 4. 2 Challenges faced .......................................................................................................... 52 Table 4. 3- Challenges and stages ................................................................................................. 54





MOSES ZHOU 1P007 0869T

CHAPTER ONE- INTRODUCTION

1.0 Introduction

Planning in the construction industry is defined as the coordinating of building activities,

assigning and allocating resources to successfully complete the project along the three critical

dimensions of time, cost and quality (Greenwood, 1973). Scheduling is the assignment of desired

start and finish times to each activity in the project within the overall time cycle required for

completing according to plan (Greenwood, 1973).

In construction different professionals are responsible for planning and scheduling ranging from

project managers, quantity surveyors and the architect. While in some organisations there are

planners who are specifically trained in planning and scheduling. In planning and scheduling the

responsible personnel uses various techniques such as PERT, CPM and Gantt charts. The use of

various techniques is to estimate the duration of the project as well as the resources quantities

that are required to accomplish a given project.

Project planning and scheduling is done to increase the likelihood that a project will be

implemented efficiently, effectively and successfully. According to Humprey (1997), planning

is in three phases. Phase one is done prior to the project commencement. The second phase is

done concurrently with the construction and last but not least when the construction project has

been completed. Planning and scheduling at different stages seeks to achieve different purposes.

Before the project starts planning and scheduling seeks to provide a basis for agreeing on the cost

and schedule for a project. It also helps in making commitments that can be kept. It also seeks to

identify tasks & dependency relationships between various activities, as well as the completion






date. It also identifies costs, & budget (bid & profit). It can also be a useful tool for providing a

framework for obtaining required resources.

As the project commences the reasons for planning and scheduling shifts to the provision of

guidance to the project (provides an organizing structure). It can be used as a control tool upon

which the progress can be judged. It also provides a framework for management control of the

project. Finally, after the project has been completed the purpose for planning and scheduling is

to provide a reference point for evaluating the project. This serves to avoid repetitive mistakes on

different projects.

In order for the planning and scheduling process to come up with a more realistic and balanced

plans and schedules, the three antagonistic project objectives of cost, time and quality are to be

taken into every plan for a project. The three’s interdependency is that if the project duration is

shortened then quality is likely to be compromised and project costs tend to increase. The three

elements must be kept in equilibrium as illustrated by Figure 1.1 below.

Figure 1. 1- Cost-Time-Quality triangle

Time

Quality Cost

Source: Louis, 1988






Construction planning and scheduling should take into account risk in time and cost estimates. A

number of techniques in use in the construction industry have a number of shortcomings such as

failure to take into account risk. Techniques such as CPM, Gantt chart and WBS fail to take into

account risk and uncertainties when it comes to construction projects. The reason being the

techniques were inherited from other different disciplines that have disregard to the construction

industry (Nelson, 1997).

1.1 Back ground

Planning techniques in an economy are generally attributed and traced back to the Bolshevik

revolution in Russia in 1972. The evolution of scheduling closely tracks the development of

computers (Dua, 2008). However, the establishment of the actual planning and scheduling

techniques can be attributed to the scientific school of thought. The Work Breakdown Structure

(WBS) and Project Evaluation and Review Technique (PERT) were both developed by the

United States Department of Defense (DOD) in 1957. Gantt, an American engineer and social

scientist is credited with the development of the bar chart (Gantt chart) in 1917. Walker is also

credited with the development of the critical path method (CPM) in1956.

There are numerous methods being used to plan and schedule projects, many of which are old in

origin (Abdulrahman, 2002). Some of the techniques are Project Evaluation Review Techniques

(PERT), Work Breakdown Structure (WBS), Line of Balance (LOB) and Petri-Nets. However

most project managers are acquainted with the type of schedule which is prepared by

management and consists basically of a list of dates on which certain items are to take place or to

be completed. They are familiar with the Gantt chart, which supplies additional information by

showing the beginning and ending of each portion of the work as well as the total scope of the






project. The decision concerning the method to be used for the planning and scheduling of a

project rests with the project manager, or planner, and the supporting staff. Success or failure

largely depends upon the knowledge of available, procedures and the ability to choose the

method, which will be of maximum benefit to the company.

Planning and scheduling is one of the factors contributing to project success as stated in the

Journal of Construction Engineering and Management, ASCE , Vol. 130, No. 4, 2004, pp. 598,

states that “Comprehensive planning and the efficient layout of site facilities are important

factors contributing to successful construction management”. Therefore planning and scheduling

should be a core objective of project managers.

1.2 Problem statement

Flanagan and Norman (1993) noted that, in terms of scope, cost, time and quality, the

construction industry, perhaps more than most, is particularly at risk. They add that this risk is

often not dealt with adequately, resulting in poor performance with increased costs and time

delays. Indeed, many construction projects are faced by planning and scheduling problems

causing the projects to finish beyond their predetermined due date. As a result, there are usually

provisions for delay damages in the contract terms, which in turn is a major problem for project

managers and practitioners. Through liquidated and ascertained damages the contractor suffers

losses for failure to complete within the agreed time limits. In the event that the project fails to

perform its intended function the contractor’s goodwill suffers. And in the case of a cost overrun,

either the client or the contractor or even both suffer accordingly. Construction planning and

scheduling is one of the tasks that has a bearing on project success or failure and failing to plan

properly is planning to fail (Wilson, 2007).






The construction industry has one of the highest records of delayed project completions. Each

year, millions of dollars are lost because of poor time management, project control and record

keeping. For this reason, the project managers have a hugely important task governed by

established principles. To be an effective scheduler, these principles are an absolute must (Patrick

Weaver-Project Planning and Scheduling in Construction’ Training 2010).

Project managers and other personnel responsible for planning and scheduling simply transplant

tools and techniques from other unrelated disciplines such as manufacturing industry with

disregard to the construction industry (Sawhney, 2003). Due to the dynamism in the construction

industry these tools are failing to work, as a result most projects are delivered either in poor

quality or over the budgeted cost or overdue. To a worse extend some of the projects fail to

deliver at all.

Most project managers consider planning as being too time-consuming (Niclas, 2000). A

majority of the project managers make project schedules in order to get a rough picture of how to

organise different activities and what resources are needed. Project managers can hardly see the

advantages of more planning and scheduling, and the surplus value it involves is still unclear.

But in general, planning has low status among the majority of project and company managers.

1.3 Research questions

i. Which planning and scheduling techniques are being applied in the construction

industry?

ii. How applicable are the techniques in the construction industry?

iii. What are the challenges being faced in implementing planning and scheduling tools and

techniques?






iv. What are the shortcomings and benefits of planning and scheduling?

1.4 The aim of study is:To investigate the implementation of planning and scheduling techniques on construction

projects in a bid to improve project success.

1.5 Objectives

The objectives of this study are to:

i. Identify the planning and scheduling tools that are currently under use in the construction

industry

ii. Asses the applicability of planning and scheduling in the construction industry

iii. Investigate the various challenges being faced by construction professionals in

implementing planning and scheduling techniques

iv. Investigate the shortcomings and benefits of planning and scheduling in the construction

industry.

1.6 Justification

The inherent uncertainty and complexity of construction work makes construction planning and

scheduling a particularly difficult task for project managers due to the need to anticipate and

visualize likely future events (Guo, 2009). This has attracted researchers to venture into the area

of construction planning and scheduling.

The need for construction planning and scheduling tend to increase as the size and complexity of

a project increases. Patrick, 2004 states that there is need for adequate planning and scheduling

of construction projects to sufficiently define the activities for effective communication to all






project information users. As the number of projects increases, so is the complexity of their

sequential ordering, and the need for organised planning and scheduling (Patrick, 2004).

According to this research, Patrick’s theory states that planning and scheduling complexity is

proportional to the number and size of the projects at hand. However, he did not tabulate on the

ways of making the planning and scheduling more adaptable to accommodate the increased

complexity. A research by Osborne in 2008 considered the problems associated with project

planning generally, with specific reference to construction projects. Hence the researcher will

analyse the effectiveness of construction planning and scheduling in a bid to improve the

planning and scheduling function for more complex projects.

1.7 Hypothesis

The integration of time, cost and quality in planning and scheduling enhances successful project

delivery.

1.8 Research outlineChapter 1: Introduction

This chapter will give historical background about the concept of planning and scheduling in

construction and. Justification, aim(s) and the objectives of the study will also be included here.

Chapter 2: Literature Review

The existing views about planning and scheduling will be outlined in this chapter. The researcher

will build the foundation in the subject with data from various texts, magazines, journals and

forms of construction literature. The information will help the development of further insight into

the matter.






Chapter 3: Research Methodology

How the research was conducted will be documented in this chapter. Selection of the sample,

sources of data and justification on the research techniques used will be detailed here. It will also

highlight the use of research tools such as questionnaires and guided interviews. Difficulties

encountered during research will possibly be highlighted here.

Chapter 4: Data Presentation and Analysis

This chapter will cover presentations, analysis, evaluation and application of the results produced

by the study. Data will be presented in various forms such as graphs, charts and tables. The

interpretation of data is done in this chapter.

Chapter 5: Conclusion

Conclusions drawn from the research will be summarized here.






CHAPTER TWO- LITERATURE REVIEW

2.0 Introduction

Project planning and scheduling system present a solution to structuring and managing the

complexity of construction projects while accepting the vast variability between projects and a

high level of uncertainty. (Russel, 2000). There are a number of planning and scheduling that are

implemented in the construction industry. In this chapter the researcher will analyze these

techniques.

2.1 Definition of terms

Planning means thinking about and documenting what needs to be done, defining and

coordinating certain activities, assigning and allocating resources to successfully complete the

project along the three critical dimensions of time, cost and quality. (Alaa A, 2003). Planning as

defined by AACE is, "the determination of a project's objectives with identification of the

activities to be performed, methods and resources to be used for accomplishing the tasks,

assignment of responsibility and accountability, and establishment of an integrated plan to

achieve completion as required”

Scheduling A schedule determines when the work must be done. Scheduling can be

accomplished by a variety of methods ranging from simple bar chart to sophisticated network

schedule. (ِAlaa A, 2003). Scheduling as defined by AACE is: “The assignment of desired start

and finish times to each activity in the project within the overall time cycle required for

completion according to the plan , Process of converting a general or outline plan for a project

into a time-based schedule based on available resources and time constraints and Another






clarification of the term scheduling is, Scheduling is the ordering of the activities within a plan

utilizing additional discretionary logic restraints and constraints ... based upon the discretion of

the project manager ... and including adjustments to activity-specific and total resource usage

that may be directed.”

Baseline scheduling the original plan against which your progress is measured. The baseline

represents the original plan at the onset of the project of what you expect to happen. The

baseline is saved once the schedule is presented to the stakeholders and other interested

parties, and has been agreed to by all parties.

Client means a person for whom a project is carried out, in the course or furtherance of a

trade, business or undertaking, or who undertakes a project directly in the course or

furtherance of such trade, business or undertaking. The Client is the person or company, with

the controlling interest in the project. Generally the Client will retain a significant level of

control over the assessment and appointment of Designers and Contractors for a project.

(Health and Safety Authority, Metropolitan Building, 2009 )

Contractor is an organization or individual that contracts with another organization or

individual (the owner) for the construction of a building, road or other facility.

Project manager is a professional in the field of project management. Project managers can

have the responsibility of the planning, execution, and closing of any project, typically

relating to construction industry, architecture, computer networking, telecommunications or

software development.






Critical path the necessary path or sequence from start to finish, determining the time

needed for completion; the longest most time-consuming path in a network. (lexion

dictionary )

2.2 Planning and scheduling techniques

Planning and scheduling techniques are various tools used in planning and scheduling of

projects, the said techniques include among others the following: CPM, PERT, Gantt chart, LOB

and Petri nets. In applying the planning and scheduling techniques one is supposed to first

breakdown the project into work packages and with the aid of network diagrams identifies the

relationship and sequence of the work flow. PMBOK, (2004)

Let’s consider the network for the following table of project duration in table 2.1.

Table 2. 1- Network data

Activity Activity duration in

weeks

Immediate

predecessor

A 2 -

B 4 A

C 2 A

D 3 B,C

Source: Project management, Cooper, 2000

The AON network for the above table will be as shown by Figure 2.1.






Figure 2. 1- Activity on node network diagram

2

4 2

3

Source: Archibald & Villoria, "Network-Based Management Systems (PERT/CPM)," John Wiley

& Sons, 1967

2.2.1 Project Evaluation and Review Technique (PERT)

PERT is a project management technique for determining how much time a project needs before

it is completed. The time required to complete various activities in a construction project is

generally not known. Thus PERT incorporates uncertainties in activity times in its analysis. It

determines the probabilities of completing various project stages by specified deadlines. From

START

A

CB

D

FINISH






these various deadlines, it goes on to calculate the expected time to complete the project. This is

done by assigning a best, worst, and most probable completion time estimate time. These

estimates are used to determine the average completion time. This is a scheduling tool that uses a

weighted average formula to predict the length of activities and the project. (Solberg, 2000)

According to Don Philips and James Solberg an important and extremely useful by-product of

PERT analysis is its identification of various “bottle-necks” in the project. In other words, it

identifies the activities that have the high potential of causing a delay in completing the project

on schedule. Therefore even before the project starts the project manager already knows where

he can expect delays. He can then take the necessary preventive measures to reduce possible

delays so that the project schedule is maintained.

PERT was developed in the Navy during the late 1950, to facilitate the development of a fleet of

missiles. The development involved the coordination of a number of private contractors. The

coordination by PERT was successful such that the project was completed 2 years ahead of

schedule. This resulted in its further use including the construction projects.

The PERT Three-Estimate to be obtained for each activity is:

Most likely estimate (m) - estimate of the most likely value of the duration,

Optimistic estimate (o) - estimate of the duration under the most favourable conditions,

Pessimistic estimate ( p) - estimate of the duration under the most unfavourable conditions.

John Willey, 1957

The intended location of these three estimates with respect to the probability distribution is

shown in Fig. 2.2. Thus, the optimistic and pessimistic estimates are meant to lie at the extremes

of what is possible, whereas the most likely estimate provides the highest point of the probability






distribution. PERT also assumes that the form of the probability distribution is a beta distribution

(which has a shape like that in the figure below),

Figure 2. 2- Beta distribution


& Sons, 1967

In order to calculate the mean and variance of the probability distribution the distribution of the

durations is modelled by a beta distribution. For most probability distributions such as the beta

distribution, essentially the entire distribution lies inside the interval between (mean minus 3

times variance) and (mean plus 3 times variance). (For example, for a normal distribution, 99.73

per cent of the distribution lies inside this interval.) Thus, the spread between the smallest and

largest elapsed times in Fig. 2.1 is roughly 6 times variation. Therefore, an approximate formula

for variance is

[ ( Pessimistic - Optimistic ) / 6]²

Similarly, an approximate formula for the mean is






(Optimistic + 4 x Most likely + Pessimistic) / 6

The procedure for the PERT is more or less similar to that of the CPM except for the information

that is used in the process as inputs data. Unlike single estimate used in CPM it employs three

estimate of time namely the pessimistic, optimistic and the probabilistic. And the expected time

of an activity is arrived at by applying a formula: (o+4m+p)/6, the process is done for each and

every activity as illustrated in the following table.

Table 2. 2- PERT Network data

Activity Optimistic

time

Most

likely time

Pessimistic

time

Mean Variance

A 1 2 3 2 0.11

B 1 3 5 3 0.44

C 2 3 6 3 0.44

D 1 4 6 4 0.69


& Sons, 1967

The last two columns show the approximate mean and variance of the duration of each activity,

as calculated from the formulas. After the expected time has been calculated it then follows the

normal procedure of the Critical Path Method.






Properly implemented PERT can explicitly define and make visible dependencies (precedence

relationships) between the WBS elements. It also facilitates identification of the critical path and

makes this visible helps identification of early start, late start, and slack for each activity. PERT

provides for potentially reduced project duration due to better understanding of dependencies

leading to improved overlapping of activities and tasks where feasible. The large amount of

project data can be organized & presented in diagram for use in decision making.

However, there can be potentially hundreds or thousands of activities and individual dependency

relationships. The network charts tend to be large and unwieldy requiring several pages to print

and requiring special size paper

2.2.2 Critical Path Method

CPM is a network diagram used to present the relationships between the various work packages

that are involved in a project. It is also used to calculate the total time required to complete a

project.

Analysis technique used in complex project plans with a large number of activities. CPM

diagrams all activities, time required for their completion, and how each activity is related to the

previous and next activity. A sequence of activities is called a 'path,' and the longest-path in the

diagram is the critical path. It is 'critical' because all activities on it must be completed in the

designated time, otherwise the whole project will be delayed. The critical path only determines

the longest path without taking into consideration risk associated with construction projects.

CPM permits systematic reviewing of current situations as they arise. So, allowance can be made

for the effects of uncertainties in the original planning. It enables, also, for re-evaluation of future

uncertainties to be made, and remedial measures for those operations that require correction or






acceleration (Woodhead, 1976). However, for complex projects, a CPM schedule becomes

extremely detailed hence can cause confusion. CPM does not admit and adress the presence of

loops or feedback used in repetitive processes. According to Cole (1991) a CPM - does not

reflect site conditions accurately and a contractor, when using the technique, should make

allowances for this during the planning process

2.2.3 Gantt chart

The Gantt chart is mainly used to schedule various resources for the purposes of procurement

and delivery schedules of materials. It exactly indicates when the resources are needed for

purposes of prioritization in cases of competing work packages. A Gantt chart is a type of bar

chart that illustrates a project schedule. Gantt charts illustrate the start and finish dates of the

terminal elements and summary elements of a project.

Terminal elements and summary elements comprise the work breakdown structure of the project.

Some Gantt charts also show the dependency (i.e., precedence network) relationships between

activities. Gantt charts can be used to show current schedule status using percent-complete

shadings and a vertical "TODAY" line as shown overleaf.

In the following example with four activities b and c to start after a. if the project is to start on

Monday and the critical path appears to be 5, according to the chart below. If the progress is

checked at the close of business on Wednesday, activity a and b are finished but c is half done an

d has not been begun.






Figure 2. 3- The Gantt chart

task

name predecessor duration Monday Tuesday Wednesday Thursday Friday

A - 2 100%

B A 1 100%

C A 2 50%

D C,D 1 0%

today


& Sons, 1967

Gantt charts have become a common technique for representing the phases and activities of a

project work breakdown structure (WBS) (Gantt, 1974), so they can be understood by a wide

audience all over the world.

However, a common error made by those who equate Gantt chart design with project design is

that they attempt to define the project work breakdown structure at the same time that they

define schedule activities (Morris, 1994). This practice makes it very difficult to follow the






100% Rule. Instead the WBS should be fully defined to follow the 100% Rule, and then the

project schedule can be designed.

Although a Gantt chart is useful and valuable for small projects that fit on a single sheet or

screen, they can become quite unwieldy for projects with more than about 30 activities. Larger

Gantt charts may not be suitable for most computer displays. A related criticism is that Gantt

charts communicate relatively little information per unit area of display. That is, projects are

often considerably more complex than can be communicated effectively with a Gantt chart.

Gantt charts only represent part of the triple constraints (cost, time and scope) of projects

(Peter, 1994), because they focus primarily on schedule management. Moreover, Gantt charts

do not represent the size of a project or the relative size of work elements, therefore the

magnitude of a behind-schedule condition is easily miss-communicated. If two projects are the

same number of days behind schedule, the larger project has a larger impact on resource

utilization, yet the Gantt does not represent this difference.

Although project management software can show schedule dependencies as lines between

activities, displaying a large number of dependencies may result in a cluttered or unreadable

chart.

Because the horizontal bars of a Gantt chart have a fixed height, they can misrepresent the

time-phased workload (resource requirements) of a project, which may cause confusion

especially in large projects. In the example shown in this article, Activities E and G appear to

be the same size, but in reality they may be orders of magnitude different. A related criticism is






that all activities of a Gantt chart show planned workload as constant. In practice, many

activities (especially summary elements) have front-loaded or back-loaded work plans, so a

Gantt chart with percent-complete shading may actually communicate wrongly the actual

schedule performance status.

2.2.4 Work break down structure

A work breakdown structure (WBS) in project management and systems engineering, is a tool

used to define and group a project's discrete work elements in away that helps organize and

define the total work scope of the project.

A WBS element may be a product, data, a service, or any combination. A WBS also provides the

necessary framework for detailed cost estimating and control along with providing guidance for

schedule development and control. Additionally the WBS is a dynamic tool and can be revised

and updated as needed by the project manager

The Work Breakdown Structure can be described as a tree structure, which shows a subdivision

of effort required to achieve an objective; for example a program, project, and contract. In a

project or contract, the WBS is developed by starting with the end objective and successively

subdividing it into manageable components in terms of size, duration, and responsibility (e.g.,

systems, subsystems, components, tasks, subtasks, and work packages) which include all steps

necessary to achieve the objective.

The Work Breakdown Structure provides a common framework for the natural development of

the overall planning and control of a contract and is the basis for dividing work into definable






increments from which the statement of work can be developed and technical, schedule, cost,

and labor hour reporting can be established.

A work breakdown structure permits summing of subordinate costs for tasks, materials, etc., into

their successively higher level “parent” tasks, materials, etc. For each element of the work

breakdown structure, a description of the task to be performed is generated. This technique

(sometimes called a System Breakdown Structure) is used to define and organize the total scope

of a project. The WBS is organized around the primary products of the project (or planned

outcomes) instead of the work needed to produce the products (planned actions). Since the

planned outcomes are the desired ends of the project, they form a relatively stable set of

categories in which the costs of the planned actions needed to achieve them can be collected. A

well-designed WBS makes it easy to assign each project activity to one and only one terminal

element of the WBS. In addition to its function in cost accounting, the WBS also helps map

requirements from one level of system specification to another, for example a requirements cross

reference matrix mapping functional requirements to high level or low level design documents.

The Work Breakdown Structure provides a common framework for the natural development of

the overall planning and control of a contract and is the basis for dividing work into definable

increments from which the statement of work can be developed and technical, schedule, cost,

and labor hour reporting can be established.

It also permits summing of subordinate costs for tasks, materials, etc., into their successively

higher level “parent” tasks, materials. And if its a well-designed WBS makes it easy to assign

each project activity to one and only one terminal element of the WBS.






However, the WBS only specifies what will be done, not how or when. And to some extend does

not exhaust the whole list of work to be undertaken.

According to the Project Management Institute, 2004 many inexperienced project managers

move too quickly from the scope statement to the activity sequencing processes. This practice is

a mistake and often leads to activity omissions and inaccurate plans. PMI stresses the importance

of first creating a work breakdown structure (WBS), and then moving to activity management

processes.

2.2.5 Line of Balance

Line of Balance (LOB) is a management control process for collecting, measuring and presenting

facts relating to time, cost and accomplishment - all measured against a specific plan. It shows

the process, status, background, timing and phasing of the project activities, thus providing

management with measuring tools that help to:

Comparing actual progress with a formal objective plan.

Examining only the deviations from established plans, and gauging their degree of severity with

respect to the remainder of the project.

Receiving timely information concerning trouble areas and indicating areas where appropriate

corrective action is required.

Forecasting future performance.

The "Line of Balance" is a graphic device that enables a manager to see at single glances, which

of many activities comprising a complex operation are "in balance" - i.e., whether thosewhich

should have been completed at the time of the review actually are completed and whetherany






activities scheduled for future completion are lagging behind schedule. The Line of Balance

chart comprises only one feature of the whole philosophy which includes numerous danger

signal controls for all the various levels of management concerned.

Properly implemented LOB enables the comparing actual progress with a formal objective plan.

It helps examining the deviations from established plans, and gauging their degree of severity

with respect to the remainder of the project. Enables the managers to receive timely information

concerning trouble areas and indicating areas where appropriate corrective action is required. It

enables forecasting of future performance. It enables maximum resource utilization Minimizes

interruption in on-going process, including hiring-and-firing.

However, LOB does not apply to one off projects, it only applies for repetitive projects. For

which the control standards has been predetermined and set from a similar past project, carried

under similar conditions, otherwise it fails.

2.2.6 Petri Nets

Petri Nets are graphical and mathematical modeling tools that can be used to perform static and

dynamic modeling of existing or new projects. Petri A is generally considered as the originator

of the concept of Petri Nets (Petri 1966). Systems that are characterized as being concurrent,

asynchronous, distributed, parallel, non-deterministic, and stochastic can be effectively modeled

using the Petri nets. A Petri Net consists of four main types of modeling elements called places,

transitions, arcs, and tokens (Khator, 1994).

Statistical Distributions: A transition that represents a work task or a group of work tasks can

be assigned a stochastic time and cost estimate. Construction managers can utilize a large






number of a statistical distributions to estimate the duration and cost of a work task. During the

dynamic simulation of the Petri Net based project network the stochastic estimates are utilized to

provide overall project time and cost estimates that are more realistic. This allows seamless

incorporation of risk and uncertainty factors in the project schedule.

Probabilistic Arcs: In addition to the statistical distributions, Petri Net based scheduling

technique also provides modeling tools that can be utilized to incorporate uncertainty in the

construction logic. A probabilistic arc can be utilized in the Petri Net based project network to

model this uncertainty. In the traditional network techniques branching is done on a deterministic

basis, no cycling is allowed in the network, and work tasks are always completed successfully as

the concept of failure is non-existent. This deficiency is removed in the Petri Net based

scheduling through the use of the probabilistic arcs.

Petri nets enable a hierarchical and modular decomposition of complex construction projects

which can reduce the complexity of the project network. It employs cycling and probabilistic

arcs can be used to model uncertainty in the construction logic. Uncertainty in the time and Petri

Net Based Simulation of Construction Schedules cost estimates of the work tasks can be

modeled by using appropriate statistical distributions; and modeling of shared resources and

dynamic allocation of resources in a project network by using fusion places allows a the

construction manager to foresee resource availability problems. (Anil 1997)

Allows for a dynamic Resource Allocation. Resources on a construction project are shared by

a number of work tasks. For example, a tower crane assigned to a high- rise building project is

used to perform functions such as lifting a concrete bucket, arranging structural steel members,






and unloading fabricated members from trucks. In order to realistically schedule a construction

project it is essential to model the dynamic allocation and usage of resources. The fusion place

capability allows places in a Petri Net that exist in different locations in the network to act

functionally as if they were the same place. Modeling of resources that are shared by a number of

work tasks on a construction project is accomplished by using fusion places in conjunction with

colored tokens.

Enables the Identification of Resources, the various resources being utilized on a construction

project are modeled by tokens that dynamically move from transition to transition in the Petri

Net based project network. These resources are identified by the “color” of the tokens. The

modeler is allowed to define more than one type of token in a given Petri Net by assigning a

color or type to the token. These types of tokens are called colored or typed tokens and the

resulting Petri Nets are called Colored Petri Nets (Jensen 1992).

2.3 Applicability of Planning and scheduling techniques

The planning and scheduling techniques employed in the construction industry do not fit in very

well. According to Anil 1997 Traditional network based planning and scheduling methods do not

Consider these important characteristics of construction projects during schedule development.

The question of applicability lies on the ability of the particular planning and scheduling

techniques to address cost, time and quality problems of construction projects.

2.3.1 Critical Path Method

The Critical Path Method (CPM) has been widely used in the construction industry since its

invention in the 1950s. The CPM applications have well served project managers in preparing

project proposals, managing personnel and resources, tracking delays and change orders,






instituting as a basis for progress payments, and coordinating with subcontractors (Jaafari 1984).

However, its suitability has been widely criticized and three major drawbacks that can be

identified as follows:

Inability to cope with non-precedence constraints- in the real world, construction posses

various kinds of constraints. The constraints range from physical constraints (i.e. topology,

space, safety, and environment), contract constraints (i.e. time, cost, quality, and special

agreement) to resources and information constraints (i.e. availability and perfection).

Unfortunately, CPM considers only time and precedence constraints among activities (Deng,

2000). Its underlying network representation is proven to be inadequate to represent and integrate

more problems in construction management (Bibany 1997)

Difficulty in plan evaluation and communication- The CPM schedule is graphically

presented in either a form of Gantt chart (Bar chart with relationships) or a form of precedence

diagram. To evaluate and communicate the plan, project participants must mentally associate this

schedule information with the description of the physical building (i.e. drawings and/or 3D

project model) as well as other technical information (i.e. specifications and method statements).

This has been proven difficult especially when there is a need to analyze effects of changes to the

overall sequence of construction (McKinney and Fischer 1998). This is in other words, failure to

accommodate sensitivity analysis.

Inadequacy for work-face executions- As projects enter their construction phase, detailed

short term planning is delegated to engineers, superintendents, or foremen. Rather than

employing the CPM, simple Bar chart or activity lists are dominant techniques for this detailed

planning (Mawdesley et al. 1997). Several studies provide convincing reasons why the CPM is






not widely utilised. Levitt et al. (1988) stated that the existing CPM tools do not provide

adequate support for analysis of constraints at operational level. Resource allocation, smoothing

or leveling procedures are incapable of ensuring full continuity for a production crew or process

(Jaafari 1984). For complex projects, field personnel find the CPM schedules confusing and,

therefore, less useful (Pultar 1990). Large amount of efforts are required to re-plan and redraw

the network each time it was updated (Jaafari 1996). Furthermore, the CPM has inflexibility and

lack of expressiveness to cope with the varied pattern of construction in the field (Jaafari 1996;

Choo et al. 1999).

2.3.2 Project Evaluation Review Technique

The application and applicability of PERT in the construction industry is more or less similar to

CPM. But on top of highlighting the critical path and everything else like the CPM it goes a step

further to take into account the fact that the construction industry is not certain. In terms of

relevance to the construction industry it can be ranked before the CPM. Furthermore, PERT

enables sensitivity analysis where the management can assume the worst case scenario as well as

the best case.

2.3.3 Gantt chart

Gantt charts are simple to understand and easy to construct, they are used by most project

managers for all but the most complex projects. It can be applied in project planning and

scheduling. Examples of field of application are the design of any complex projects. (Chase,

2003). However, its applicability is limited to a reasonable number of activities, otherwise they

wont be presentable on paper.






2.3.4 Work breakdown structure

Work Breakdown Structure (WBS) technique is used to organize and comprehend projects by

breaking them into progressively smaller pieces until they are a collection of tasks or work

packages depending on the nature of the project. The WBS is not a work schedule; it does not

contain any information as to when or in what order or precedence tasks will be accomplished.

Successful WBS's are built as an iterative process by examining a project's goals, deliverables,

constraints, and technical attributes. In addition to identifying the project deliverables, the WBS

should also identify activities related to the management of the project. These include tasks

related to project startup, management, and closeout. For example, the WBS should include

testing and quality assurance activities; it should also include items necessary for the successful

pursuit of project tasks as obtaining legal permits.

When it comes to the practical ground, not all the construction projects are divisible into smaller

units. And in itself WBS can not be a major technique, the small units need to be arranged with

the aid of other techniques.

2.3.5 Line Of Balance

In the international literature the view has been that LOB is basically a tool for use where the

nature of the projects is repetitive (Ardit et al. 2002). However, Seppanen 2002 argued that

regardless the difficulty of a project, the main activities is the same in every project. This is to

say LOB is mostly applicable to repetitive projects more than it does with one off projects.

However to some extent it can be used as a major planning and scheduling technique like any

other.






2.3.6 Petri nets

The problem with the set-marking approach is that when the number of tokens get large there

will be extensive pattern matching. The maximum number of pattern matches that have to be

performed to verify whether a transition t can re is given by the expression. (Enger, 2005). This

makes the Petri nets not very much applicable for huge construction.

2.4 Challenges to the Planning and Scheduling Process

2.4.1 Cost

Planning and scheduling costs include the cost of acquiring the relevant information needed to

come up with more realistic plans and schedules. This also includes the cost of putting in pace

control measures to monitor the implementation of the planning and scheduling processes. And

also the salaries of all the personnel who are wholly devoted to the planning and scheduling

including any professionals hired for the purposes of planning and scheduling of a project.

Planning and scheduling of complex projects attract costs which if not handled carefully can

render the project costs unbearable. Under normal circumstances the cost of planning and

scheduling should constitute an insignificant portion of a project. The unjustifiable increase of

planning and scheduling costs will make the cost of the project beyond the client's budget and

my lead to premature dearth of a project. On the side of the contractor's organization this will

result in loss of tenders due to exorbitant charges as they try to cover their cost of planning and

scheduling. The uncontrolled cost of planning and scheduling has been another factor that has

contributed to project managers shunning the planning and scheduling process as the costs of the

process outweigh the benefits derived from planning and scheduling. Douglas J.F 1997






2.4.2 Time

The planning and scheduling process takes vast of time. As a result many project managers who

fail to plan points on time shortages. As a result to maximize on the valuable project time the

shortest possible planning and scheduling methods must be adopted. But this should not

compromise on the quality of the plans and schedules brought by the process. The time

comprises of the time taken to gather the appropriate data for planning and scheduling. The

control features may require a lot of time if they are implemented manually. (Seppanen, 2003)

2,4.3 Human resources and skills

Planning and scheduling process like al the other professional tasks takes human effort as a result

in each and every organization that caries out planning and scheduling, it takes some personnel

in that field. But not all the people that can carryout the planning and scheduling function in a

building project. The employment of less equipped personnel I the field of planning and

scheduling function of a construction project will result in the production of poor plans and

schedules. Karen, 2004

2.5 Shortcomings and Benefits of Planning and Scheduling Techniques

2.5.1 Shortcomings of Planning and Scheduling

2.5.1.1 Expensive

Planning and scheduling adds on to the project overheads and project administration costs.

Planning and scheduling can result in employment of other none productive personnel who are

responsible for implementing the tools. By so doing the total project costs are increased.






2.5.1.2 Lack of skill

As of yet in the locality there are no universities and college programs that are tailor made for

planning and scheduling, except for some subjects provided to professionals such as Quantity

Surveying and Project Management students. Of which they do not explore all the planning and

scheduling techniques.

2.5.1.3 Demands extra resources

Planning and scheduling may demand the firm to acquire some resources to be used in the

processes of planning and scheduling such as computers and personnel who have computer

knowledge.

2.5.1.4 Require modern technology

Various planning and scheduling techniques come with different software packages that enhance

their effectiveness. Otherwise without such software the full benefits can not be attained. The

organization must keep up with the technological advancement pace.

2.5.2 Benefits of planning and scheduling

2.5.2.1Time saving

A properly implemented planning and scheduling process will result less delays as any deviation

can be noticed prior to occurrence and correct measures are taken to correct. A correct time

schedule can be set from the onset.






2.5.2.2 Cost reduction

Through minimizing the delay to project planning and scheduling reduce the costs of delay such

as liquidated and ascertained damages. These techniques can help to establish a project cash

flow and by so doing cost of capital and unnecessary borrowing are minimized. Niels, 2008

2.5.2.3 Enhances quality service

The reward for planning and scheduling of construction project results in a improved quality of

the service delivery.

2.5.2.4 Minimize riskThe risk of failure to complete the project can be noticed prior occurrence and are addressed well

in advance, therefore reduces the risk of failure to deliver the project.

2.6 Conclusion

From the above literature and perceptions of various researchers were reviewed and it shows that

the is the need to carryout a research as to identify the various challenges and benefits attained

from using the planning and scheduling techniques in the construction industry. The next chapter

details out how the research is to be carried out.






CHAPTER THREE- RESEARCH METHODOLOGY

3.0 IntroductionPlanning and scheduling is one of the key factors that determine the success or failure in one or

more aspects. As mentioned previously if a project is not carefully planned it will either fail, or

delivered late or even over and above the budgeted cost. To find obtain the data for use in this

project the researcher will employ various techniques to obtain different types data from

different sources.

3.1 Research design

Research design is described as how the research was carried. In this case the population

comprises of the construction industry in Bulawayo and Harare.

3.1.1 Sampling frame

Sampling involves the selection of subjects from a population. The population is the entire set of

people, or objects and the sample is a subset of the population. The sampling frame consist of the

construction stakeholders and these include; Clients, Contractors, Project managers and Quantity

surveyors.

3.1.2 Sample size

The used a sample size of 20. This was mainly due to the aforesaid time and resource constrains,

the researcher chose to use a sample of the population that is replica of the whole population.

The results obtained from this small group are then taken to be representative of the whole

population. The sample comprised of Contractors, Clients, Project managers and Quantity

Surveyors.






3.1.3 Target Population

The target population refers to all the possible elements that could be included in the research. In

this research, the target population is all the construction stakeholders and these include; Project

Managers practicing, Government, Private and Public clients, Contractors registered with the

Construction Federation of Zimbabwe, Architects and Quantity Surveyors registered with the

Zimbabwe Institute of Quantity Surveyors.

3.1.4 Area of study

The research is confined to Bulawayo and Harare. Mainly because the researcher assumed that

the two places will give a fair representation of the entire firms, and most of the construction

industry firms are based in these two cities.

3.2 Sampling methods

These are the various methods which will be used to draw the sample from the whole population

which was then used to collect the data used for the study. There are two major sampling

methods; these are probability and non-probability sampling. Non-probability sampling is when

the units are selected because of personal judgment and convenience. Bulawayo was selected to

be part of the population on the basis of convenience to the researcher, since its proximity to the

university. The following sampling methods were used;

3.2.1 Stratified Random Sampling

The statistical sampling method called stratified sampling is used when representatives from

each subgroup within the population need to be represented in the sample. The first step in

stratified sampling is to divide the population into subgroups (strata) based on mutually

exclusive criteria. Random or systematic samples are then taken from each subgroup. The






sampling fraction for each subgroup may be taken in the same proportion as the subgroup has in

the population. For example, if the person conducting a customer satisfaction survey selected

random customers from each customer type in proportion to the number of customers of that

type in the population. For example, in this case 20 objects are to be selected, and 15% are

contractors, 20% are clients, 30% are project managers, 15% are Architects and 20% are

Quantity Surveyors would be randomly selected. Stratified sampling can also sample an equal

number of items from each subgroup. The researcher used the various types of stakeholders as

strata because the researcher wanted to get the view of all the various stakeholders

proportionally.

Table 3. 1- Sampling strata table

Strata number Population Sample size % of frame

Strata 1 Quantity Surveyors 4 20

Strata 2 Architects 3 15

Strata 3 Project Managers 6 30

Strata 4 Contractors 3 15

Strata 5 Clients 4 20

3.2.2 Random Sampling

From the said strata a simple random sampling method was used to draw from the stratus the

actual subjects to whom the questionnaires was delivered. In this method, each item in the






population has the same probability of being selected as part of the sample as any other item. To

do this the researcher used a random number generator (calculator).

3.2.3 Snowball Sampling

From the sample established above the researcher used the snowballing method when delivering

questionnaires. In trying to find the individuals that are responsible for planning and scheduling

in different organizations, the researcher asked someone at the company. Given that the

construction industry is a small world there might be referrals by other subjects.

3.3 Sources of data

3.3.1 Secondary sources

Secondary data analysis can be defined as second-hand analysis. It is the analysis of data or

information that was gathered by some past researchers for some purpose other than the one

currently being considered. Secondary information is also valuable for generating hypotheses

and identifying critical areas of interest that can be investigated during primary data gathering

activities.

The researcher used the following secondary sources of data: Trade Journals, University Library,

Computerized Databases, the Web and professional bodies’ publications so as to get the names

of the relevant companies. From the trade journals the researcher got the status of planning and

scheduling to the construction industry.

Advantages of secondary data sources

Secondary data analysis appeared to be fast as compared to formal primary data gathering and

analysis exercises. The researcher could go through much literature within a short space of time.

And where good secondary data was available, researchers saved time and money. Secondary






research also helps the researcher to make informed primary research and complements primary

data collection

Disadvantages of secondary data sources

During the session when the researcher was reviewing the secondary data could easily become

overwhelmed by the volume of secondary data available, if selectivity is not exercised. Sources

had conflicts among themselves. And also because secondary data was not collected for the same

purpose as the original researcher had, the goals and purposes of the original researcher can

potentially bias the study.

3.3.2 Primary data sources

A primary source is a document created at the time of your research subject, about your research

subject. These documents are directly connected with the events or people being researched.

These are the sources of information collected for the first time, in trying to solve the problem at

hand. Such sources include personal interviews and questionnaire.

3.4 Research instruments

These are the various methods and tools used to gather the data from the research subjects. These

include;

3.4.1 Personal interviews

Is a one-on-one verbal interaction between the researcher and the respondent? The researcher

also did some interviews. Personal interviews were used to gather data from those respondents

who were unable to attempt questionnaires due to various reasons among which the most

dominating reason maybe time as realized from the literature of data collection.






In an interview the respondents may seek clarification on issues that are not clear. The researcher

can also probed for more information through the follow up of questions that were not asked.

The researcher can also control the respondent so that only the information that is relevant to the

study is provided.

3.4.2 Questionnaire

This is the main instrument that the researcher used to use to gather both qualitative and

quantitative data.

Advantages

The data that was gathered with the use of questionnaires was standardized and therefore,

easy to analyze;

Data was gathered quickly from a large number of respondents, since they can answer the

questionnaires independently.

The respondents were answering anonymously which may have produced more honest

answers;

Disadvantages:

Responses may be inaccurate, especially through miss-interpretation of questions in self-

completing questionnaires hence there might be need to escort the questionnaires.

Response rates were poor, because people may lack the motivation to complete or return

the questionnaire. Consequently, some sort of incentive may have to be included, for

example, a prize draw;






The complexity of designing, producing, distributing, and analyzing the questionnaires

made them expensive and time consuming;

3.5 Avoiding bias

Bias is the extent to which the estimate of an indicator found by a survey differs from its “true”

value. To avoid bias, sampling frames were designed to cover the entire target population for a

program’s evaluation effort. The researcher had to make sure that the sample that was used was

representative enough of the total population and limits to the amount of contribution one can

make were set through the use of standardized questionnaires.

3.6 Limitations and constraints

Prior to the field researcher the researcher was already of the time and resources constraints of

the period for the project. This eliminated the use of some long-term data collection methods

such as observation, and the researcher had to cut down on the size of the sample to 20. Out of

the stated 20 questionnaires only 15 were returned.

3.7 Data presentation and analysis plan

The data was collected through interviews and questionnaires and presented in graphs and charts.

And the information was analyzed using both quantitative and qualitative methods. Quantitative

data was analyzed using mechanical analysis to present the trends and patens in the findings.

Qualitative data was analyzed using content analysis of the data collected through questionnaires

and interviews.

3.8 Conclusion

The questionnaires was send out to the subjects and also interviews were arranged for those who

claim to have enough time to attend to structured questionnaires. The researcher will escort the






questionnaires to clarify on issues that are not clear. The researcher used the questionnaire as the

interview guide.






CHAPTER FOUR- DATA PRESENTATION AND ANALYSIS

4.0 Introduction

In this chapter, the researcher will present the data that was gathered through the use of

questionnaires from contractors, contractors, project managers and clients. Graphs, pie charts and

tables will be used in presenting the data in an attempt to clearly represent the research findings.

Bar graphs were used where a direct comparison of magnitude for descriptive labeled was

required. Pie charts were used where the quantity was represented by the angles of the sectors.

After data presentation the researcher will carryout a analysis where the field results are

compared with the literature review to check the differences and similarities and comment on the

results.

4.1 General information

Figure 4.1.1 on the next page tabulates the administered and the returned questionnaires, from

this table out of 4 questionnaires that were administered to Quantity Surveying firms only 3 were

returned. Out of 3 targeted architects only 2 managed to return the questionnaires. Five out of the

targeted 6 project managers returned the completed questionnaires. Two out of the targeted three

contractors returned the questionnaire. And out of the targeted population of 4 clients, only 3

managed to return the questionnaire. All the other respondents cited limited time as a cause for

failure to return questionnaires






Table 4. 1-Response rate Table

Population Number administered Number of returned Percentage response

Quantity Surveyors 4 3 75%

Architects 3 2 67%

Project Managers 6 5 83%

Contractors 3 2 67%

Clients 4 3 75%

Totals 20 15 75%

Source: Survey results 2011

Figure 4.1 below shows the experience in terms the number of years one has been working in the

construction industry. The graph approximates a normal distribution which is likely to give fair

results.

Figure 4. 1- Experience of respondents


0%

5%

10%15%

20%

25%

30%

35%

40%

0 1 2 3 4 5

P e

r c e n t a g e

Experience in years

Pecentage

Pecentage






4.2 Planning and scheduling techniques

4.2.1 Planning and scheduling techniques employed

The question required the respondents to give the various planning and scheduling techniques

that they once employed in the planning and scheduling of construction projects. Figure 4.2

bellow presents the techniques that are being used in the construction industry; the mostly used

of all is CPM, Gantt charts, WBS, PERT, LOB and Petri-nets in descending order. None of the

population indicated to have used Petri-nets. Regardless of its criticism by Jaafari due to its

rigidity and failure to accommodate changes easily it remains the industry’s widely used

planning and scheduling. This has been facilitated by the fact that the planners and schedulers in

the construction industry lack adequate knowledge on the emergence of new planning and

scheduling techniques such as Petri nets that has shown no turn up.

The respondents were asked to give reasons, justifying the frequency of use. The major reason

why they used CPM more frequently and some cited the type of projects, e.g. the use of LOB

was mostly adopted where the type of projects are repetitive.






Figure 4. 2- Techniques being used


4.2.2 Stage of Planning and Scheduling

The question required the respondents to indicate the stages at which they implement the

planning and scheduling techniques. From the results it shows that most of the respondents

implement the planning and scheduling techniques through all the project stages, except for the

contractors who indicated that they employ the techniques from the tendering through the

construction stage, since they are engaged lately. However there are some procurement methods

that allow the contractor to be engaged earlier such as the design build contract when the

contractor is given the chance to plan at the onset of the project. As indicated by some of the

despondence the use of the design build will ensure uniform schedules among the team

members. Figure 4.3 shows the responses.

1514

13

10

3

00

2

4

6

8

10

12

14

16

CPM Gantt

chart

WBS PERT LOB Petri-nets

n u m b e r o f r e s p o n d e n t s

Techniques

Employment of techniques

Number of respondents






Figure 4. 3- Stage of implementation


4.2.3 Frequency of application

The figure below presents the response on the frequency of application of the different planning

and scheduling techniques. 89% of the population indicated to frequently use CPM while only

22% indicated to use LOB frequently and none of the population indicated to have used Petri

nets frequently. This was mainly due to wide use of CPM as well as its age. Ease of

interpretation was also cited for the frequent use of the Gantt chart. This clearly shows that the

industry is adopting simpler and easy planning and scheduling techniques while shunning the

modern techniques and also mentioning the client’s failure to interpret modern techniques.

14 14 14

15 15

13.4

13.6

13.8

14

14.2

14.4

14.6

14.8

15

15.2

Inception Design Feasibility Tendering Construction

N u m b e r o f r e s p o n n e n t s

Project stage

Respondents

Respondents



An analysis of implementation of

MOSES ZHOU P007 0869T

Figure 4. 4 –Frequency of a

4.2.4 Percentage successful

The question required the res

in terms of time, cost and qu

on time, either the quality wil

presents the average industry

it shows that 60% of the proj

on time and 45% are complet

of more than one planning an

quality averaging above 50%

clearly indicates that no one

Hence it shows that they must

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

CPM PERT

89%

78%

11%

22%

P e r c e n t a g e f r e q u e n c y

planning and scheduling techniques employed in t


46

plication

ondents to show the percentage success of t

lity. From the responses it shows that if on

l be compromised or there will a budget ove

percentage successful percentages. Accordin

cts lie within the expected functionality ran

d within the budgeted cost. Only those who

scheduling technique reported better perce

and those who had used only one had po

lanning and scheduling technique can work

be blended.

Gantt

chart

WBS LOB Petri

nets

56%

33%

22%

44%

67%

78%

Techniques

he construction industry,

eir completed projects

manages to complete

run. Figure 4.4 bellow

g to the survey results

e. 50% are completed

have indicated the use

tages of time cost and

r ratings, from this it

independent of others.

Often

Seldom





This goes along with Anil

scheduling methods as not

during schedule development.

and disadvantages which

(disadvantages) under differe

Figure 4. 5- Percentage time

Source: Surve

0%

10%

20%

30%

40%

50%

60%

70%

time

50%

O

P e r c e n t a g e



47

1997, when he cited traditional network

onsidering the important characteristics of

The various planning and scheduling have a

render either more applicable (advanta

t conditions, hence a great need to complem

, cost and quality successful completion

results 2011

cost quality

45%

60%

Average percentages

bjectives


based planning and

construction projects

number of advantages

ges) or inapplicable

nt one another.

Average percentages






4.3 Applicability of planning and scheduling techniques

4.3.1 Percentage successful implementation

On average the rating for CPM, PERT and Gantt chart had a rating above 50%, whereas LOB

and WBS was rated bellow 50% and Petri nets was not rated at all. This shows that the people

who plan construction projects are more comfortable with CPM, PERT and Gantt chart, and they

are not comfortable with LOB and WBS and maybe they are not aware of the existence of Petri

nets. Figure 4.5 below illustrates the average ratings of planning and scheduling techniques.

User friendliness of some planning and scheduling techniques is the cause for a higher level of

applicability by CPM. Another reason why the applicability of planning and scheduling

techniques appears to be too low is failure to use them in the correct sequence. According to the

literature for there to be a network diagram one has to break the work into work packages and

identify sequences lest he come up with a diagram that leaves some activities out, according to

the Project Management Institute, 2004.





Figure 4. 6- Percentage appl

Source: Surve

4.3.2 Relevance of planning

The responses indicated that

nets remaining not ticked on

scheduling techniques do pro

of LOB should be limited to

be divided into small units.

analyse the type of plannin

scheduling technique to use.

0%

10%

20%

30%

40%

50%

60%

70%

CPM PE

62%

5

P e r c e n t a g e s u c c e s s



49

icability

results 2011

and scheduling techniques

CPM is the most relevant and the least releva

all the responses. The respondents suggeste

ide different results in different situations.

repetitive projects and the WBS is relevant

therwise they won’t be relevant. Hence thi

and scheduling problem before deciding

igure 4.6 below illustrates the response.

RT Gantt

chart

WBS LOB Petri nets

3%50%

44%40%

0%

Techniques

Percentage


nt was LOB with Petri

that the planning and

hey cited that the use

where the projects can

s calls for the need to

on the planning and

Percentage





Figure 4. 7-Relevance of tec

Source: Surve

4.3.3 Factors hindering plan

60% of the respondents cited

Rigidity of planning a

Lack of skill among th

Inappropriate use

Lack of cooperation fr

Reluctance to plan by

Fear of failure to meet

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

CPM

1 0 0 %

P

e r c e n t a g e r e l e v a n c e



50

niques

results 2011

ning and scheduling

he following challenges:

d scheduling techniques

e existing workforce

om the organization and project team memb

other team members

the targets

PERT Gantt

charts

WBS LOB

8 0 %

2

0 %

7

0 %

3 0 %

4

5 %

5 5 %

4

0 %

6 0 %

Planning and scheduling

Techniques


rs

etri nets

YES

NO






On rigidity of planning and scheduling techniques, the respondents gave the example of CPM as

one of the planning and scheduling that gives the duration of a construction project without

considering the probability of changes in durations. They also cited that among the existing

workforce there are no people who are aware of the new planning and scheduling techniques,

hence continuous use of old techniques like the CPM and PERT unblended with new ones.

Because of the aforesaid reason the planners are using the planning and scheduling techniques

inappropriately.

The respondents pointed out the need to avoid the use of rigid techniques, e.g. replacing CPM

with PERT. They also cited the need to provide adequate education on the planning and

scheduling techniques to the workforce through the organizing of seminars and workshops. The

organization should try as much as it can to ensure total commitment from the workforce to the

planning and scheduling processes. They also cited the need to make use of more than one

technique when planning for a project.

The respondents also cited the need for flexibility of planning and scheduling techniques, since

the construction industry is prone to a number of risks.

4.4 Challenges faced when implementing planning and scheduling techniques

4.4.1 The challenges

The question requested the respondents to state the challenges faced when they implement the

various planning and scheduling techniques. The challenges and the proportion of respondent

who cited it in common provided were as illustrated in Table 4.2.






Table 4. 2 Challenges faced

Challenge Proportion

Lack of adequate funding to the planning and scheduling process 90%

Lack of up-to-date information on which the planners should base their

plans

70%

Lack of skills among the workforce 50%

Resistance to change by the workforce 60%

Instability economic environment 65%

Difficulty to plan for breakdowns and repair work 70%

Subcontractors missing deadlines 40%

Adverse shortages of labour and materials 90%


Because the top management does not recognize the importance of planning and scheduling

process they usually do not provide for expenses in connection with planning and scheduling,

hence at times there are no funds set aside. Sometimes higher inflation rates quickly erode the

plans and schedules. Failure to meet the agreed deadlines by subcontractors can render the

existing plans and schedules invalid. Some adverse shortages of resources beyond what can be

provided for lead to delays; hence the plans and schedules fail to hold water. The scoring of

percentages that are more than 50% shows that the challenges are common in the construction

industry however they did not agree on failure to meet deadlines by subcontractors which

disqualifies it from the challenges to planning and scheduling.






4.4.2 Stages at which challenges are encountered

The question required the respondent to state the stages at which they encounter various

challenges. The table bellow presents the stages at which the challenges show up as indicated by

the majority of the respondents. As indicated in the table bellow, depending on the type of the

challenge some can be felt before the commitment stage, e.g. the shortage of funds. Because the

main objective will be to keep the cost as minimum as possible, the budget for planning and

scheduling will be constrained. Some do popup at all the stages of construction project and most

dangerous of all are the ones that only appear when the construction work has started, these are

expensive to rectify.

The respondents suggested the involvement of all the project team members and organizational

members to remove the hurdle of resistance and funding issues. They also cited the need to

maintain a database of information for planning purposes. The need for a realistic initial plan in

terms of time, cost and quality was also mentioned, accompanied by a close monitoring and the

provision of adequate training to the workforce.

Lack of finance to the process reduce the quality of plans, hence increase the chances of cost and

time overruns and most likely, the quality will be compromised as one tries to bring the project

to an unrealistic schedule. In short the respondents cited poor quality, cost and time overruns as

the effects of the challenges.






Table 4. 3- Challenges and stages

Challenges Stage

Lack of adequate funding to the planning and scheduling process Before commitment

Lack of up-to-date information All stages

Lack of skills among the workforce During construction

Resistance to change by the workforce All stages

Instability economic environment During construction

Difficulty to plan for breakdowns and repair work All stages

Subcontractors missing deadlines During construction

Adverse shortages of labour and materials During construction


4.5 Shortcomings and benefits of planning and scheduling

The respondents were supposed to state the shortcomings of planning and scheduling process.

The respondents highlighted the following shortcomings:

Improper planning and scheduling results in unnecessary costs

Requires labour hours, which are subtracted from the core business of the organization

Requires training of the workforce, thus adding to the costs of the firm

Requires an investment into machinery and the planning software.






The respondents were supposed to set out the measures that they take to minimize the

shortcomings of planning and scheduling. They cited the need for proper use of planning and

scheduling techniques to cut down on unnecessary costs. They also highlighted the need to use

less demanding planning and scheduling techniques in terms of labour hours. They also cited the

need to replace the domestic with hired experts who has the best knowledge on planning and

scheduling and by so doing the core staff will be left out to carry their core duties.

However, the respondents pointed out the rewards for proper project planning and scheduling

which are as follows:

Improved degree of certainty of project completion

Completion of projects on time within the budgeted cost and quality parameters

Avoid shortages of resources during the construction stage

Ensure profit maximization through the avoidance of less viable projects as noted during

the planning process.

As detailed in the results planning and scheduling has a bearing on project success on time cost

and quality. With a greater weight given to correct planning and scheduling procedures in

carrying out the process. To test the hypothesis the number of planning and scheduling employed

versus the success that was recorded by the individual companies and an approximately direct

relationship. The relationship yielded the following equation:

y = 0.101x + 0.23

And a correlation of R2= 0.936, which shows a high degree of correlation. The graph was also

plotted bellow to illustrate the relationship between employment of techniques and






Figure 4. 8- Planning and scheduling vs. Success


Therefore, from the above analysis the researcher can conclude that the integration of time, costand quality enhances successful project delivery.

4.6 Summary

From the above findings it is evident that planning and scheduling plays an important role in the

success or failure of construction projects. Most emphasis has been on proper implementation of

the planning and scheduling techniques, and in the correct sequence. In the next chapter the

researcher concludes and recommends for further studies.

y = 0.101x + 0.230

R² = 0.936

0

0.10.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 2 4 6 8

P e r c e n t a g e s u c c e s s

Number of techniques

Percentage success vs number of techniques

Percentage projects

success

Linear (Percentage

projects success)






CHAPTER FIVE- CONCLUSIONS AND RECOMMENDATIONS

5.0 Introduction

The study was undertaken to analyse the implementation of planning and scheduling techniques

employed in the construction industry of Zimbabwe. In the previous chapter the data was

presented and analyzed in relation to the implementation of various planning and scheduling

techniques in the construction industry. The benefits and shortcomings of planning and

scheduling, factors that affect the applicability of planning and scheduling techniques and the

various challenges that hinder the planning and scheduling process.

5.1 Conclusion

From the analysis in the previous chapter it was shown that the players in the construction

industry are to some extend aware of the existence of various planning and scheduling

techniques, but their use is heavily skewed towards the very old planning and scheduling

techniques such as CPM and PERT. It also revealed that not even one of the respondents have

used Petri nets. Hence there is greater need to try new planning and scheduling techniques.

Another important point to note is the need for use of more than one planning and scheduling

technique at a time as they cover up each other’s loopholes. Another suggested point was the use

of a continuous planning and scheduling process running from the onset to project handover with

a close monitoring system in place.

Construction stakeholders approved some of the planning and scheduling techniques as they

provided a rating that was above average with just a few failing to score above average on

percentage applicability.






The construction stakeholders also pointed out the various benefits that one may enjoy due to

proper planning and scheduling techniques and this was mainly improved quality on delivery,

meeting the expected deadlines and completion of projects within the budgeted cost. Therefore,

the assumption that “The integration of time, cost and quality in planning and scheduling

enhances successful project delivery” is true as evidenced by the responses.

5.2 Recommendation for further studies

The integration of time, cost and quality in planning and scheduling enhances successful project

delivery. This has been established through this research but the measures that need to be taken

to improve the planning and scheduling processes and techniques were not fully explored.

Further to this there is need for advocating for new upcoming planning and scheduling

techniques.






Bibliography

1. Amedeo, C (2008) Rapid prototyping of construction planning and scheduling

2. Anil, S (1997) Petrinets based simulation of construction schedules, Kalamazoo, USA

3. Antonio, B (2008) Project scheduling under multiple resource constrains using a general

algorithm, Porto, Portugal

4. Ashworth, A (1999) Cost studies of buildings, Prentice hall, UK

5. Cohn, M (2006) Angile estimating and planning, Prentice Hall, New York

6. David, A (2008)Scheduling with sure track, second edition, Library of congress, USA

7. Dellol, P (2010) Resource optimal planning for an autonomous planetary vehicle,

University of Chiet, Italy

8. Dennis, B (2000) Cost of quality, Quality planning and the bottom line, Ancaster, Canada

9. Emad, E (2007) Scheduling and cost optimization of repetitive projects using generic

algorithm, Alexandria, Egypt

10. Foster, G (1996) Construction site studies, production, administration and personnel,

Britain library, London

11. France, A (2005) Advanced planning and scheduling systems, Marraketh, Morocco

12. Haris, F (1987) Worked examples in construction management, Granad Publishing,

Britain

13. John Wiley ( 1967) Archibald & Villoria, "Network-Based Management Systems

(PERT/CPM),

14. Julin, H (2002) Construction project planning and scheduling with uncertainty resource

constrains, Polytechnic University, Shangai

15. Louis, J (1988) Project planning and management, Library of Congress, USA

16. Murray, B (2007) Faster construction project with CPM, McGraw hill, USA






17. Niclas, A (1994) Reengineering of project planning, Lund Swedesh

18. PMBOK, (2004) A guide to project management, 3rd

edition, Newton Square

19. Rong, Y (2003) Non unit based planning and scheduling of repetitive construction

projects, National Central University, Taiwan

20. Russell, K (2007) Practical site planning and management of work flow, Unitec, New

Zealand

21. Wails, M (2010) Construction scheduling using critical path analysis with separate time

sequence, Ontario, Canada





APPENDIX 1: QUESTI

NATIONAL

RE

Research Topic: analysis

employed in the constructio

I am a final year quantity

Technology studying my bac

department, personnel pleasequestions to above topic.

All information obtained is st

have any inquires ple

[email protected]

Surveying, NUST-PO BOX

Thank you for your time and t

Yours Truly,

____________

Zhou Moses



61

ONNAIRE

NIVERSITY OF SCIENCE AND TECHN

EARCH SURVEY QUESTIONNAIRE

of the applicability of planning and s

industry, a case of Harare and Bulaway

surveying student at the National Univ

elor of (Honours) degree in Quantity Surve

assist the research by responding to questi

rictly confidential and is only used for the re

se contact the researcher on the

r Tel: +263 772644751 or through the d

C 939 Ascot, Bulawayo, Zimbabwe Tel; +

he timely response of the questionnaires is


LOGY

heduling techniques

rsity of Science and

ying. May your firms,

onnaire and interview

search purpose. If you

following e-mail,

partment of Quantity

9 28242

ost appreciated.






Introductory information

1. What is your firm’s area of business? (tick as applicable)

Project Management Client

Quantity Surveying Contractor

Other

2. What is your position in the company?

3. How many years have you been in the construction industry? (tick as applicable)

Less than 1 year 1 – 5 years

5 -10 years over 10 years

Section A- Construction Planning and Scheduling Techniques

There are several planning and scheduling techniques, these include; Critical Path Method

(CPM), Project Evaluation Review Technique (PERT), Gantt chart, Work Breakdown Structure

(WBS), Line of Balance (LOB), Petri nets among others.

1. Which planning and scheduling technique(s) do you use?






2. At what stage of the project do you implement these techniques? (Tick as applicable)

3. How often do you employ these techniques?

Technique Frequency

Often Seldom

CPM

PERT

Gantt chart

WBS

LOB

Petri nets

Any others

TICK STAGE

Inception

Design

Feasibility

Tendering

Construction

All stages






4. Comment on the answers provided on 3 above

5. In terms of percentage, how many projects have you completed successfully on:

Time

Cost

Quality

Section B- Applicability of Planning and Scheduling Techniques

1. What is your percentage successful implementation of the following planning and

scheduling techniques in terms of time, cost and quality?

Technique Percentage

CPM

PERT

Gantt chart

WBS

LOB

Petri nets

Specify others






2. Comment on the percentage successful implementation on (1) above

3. Are the following planning and scheduling techniques relevant to the construction

industry? (tick as applicable)

RELEVANCE

Technique yes no

CPM

PERT

Gantt chart

WBSLOB

Petri nets

Specify others

4. How relevant are these techniques?






5. What are the factors that hinder the application of the planning and scheduling?

6. What measures do you take to avoid the problems provided on (5) above?

7. What are the improvements that need to be done to the planning and scheduling to make

them suitable for use in construction planning and scheduling?

Section C- Challenges faced when implementing Planning and Scheduling Techniques.

1. What challenges do you face when implementing planning and scheduling

techniques?






2. At what stage of the project do you encounter these challenges?

Challenge Stage

3. What measures do you take to mitigate the challenges?

4. What was the effect of the challenges on time, cost and quality?






Section D- Shortcomings of planning and scheduling

1. What are the shortcomings of planning and scheduling techniques that you are

encountering?

2. What measures do you take to minimize the effect of the shortcomings of

planning and scheduling?

3. What are the benefits of planning and scheduling techniques for projects that you

worked on?

Comments





I greatly appreciate your effort in answering the questions asked in this questionnaire!

GOOD DAY.

Documents

Moses Zhou Project