THE CONSULTANCY FEE FOR STRUCTURAL DESIGN CHANGES OF

REINFORCED CONCRETE BUILDINGS IN OMAN

AMUR SALIM HAMOOD AL-HARTHY

UNIVERSITI TEKNOLOGI MALAYSIA

THE CONSULTANCY FEE FOR STRUCTURAL DESIGN CHANGES OF

REINFORCED CONCRETE BUILDINGS IN OMAN

AMUR SALIM HAMOOD AL-HARTHY

A thesis submitted in fulfilment of the

requirements for the award of the degree of

Doctor of Philosophy

Faculty of Civil Engineering

Universiti Teknologi Malaysia

MARCH 2006

ABSTRACT

Design changes in reinforced concrete buildings have for long time been a topic of prolonged arguments and frequent disputes due to their common phenomena of incidents in the construction industry. Although design changes in many cases are essential, clients, consulting engineers and contractors all have become increasingly worried about the negative parts that are associated with them. Design changes do not only affect the reliability of design but also increase the possibility of contractual disputes due to unpredictable delay and cost overrun on the original scope of work. While the cost of modifying the construction scopes is well defined in normal contract documents, but the fee of engineering changes is yet to receive more attention. Therefore this research has been developed with the aim to investigate such issues and to develop an alternative approach in evaluating the fee of altering the original scope of design work. Extensive study was performed at the initial stage of this research work in term of interviews, case studies and questionnaire survey in order to identify the sources, causes and impacts of design changes on reinforced concrete buildings as well as to establish corrective actions and preventive measures to minimise the avoidable ones. Frequency analysis and non-parametric statistical technique employed in this research to analyse the qualitative and quantitative data. It was found that engineering design changes are common in the industry and, in many cases, lead to excessive claims and disputes due to lack of appropriate and practical methods to assess their associated fee. Although there are various methods being used for assessing the fee of design changes, this study identified their limitations for practical use. Consequently, an alternative method for assessing the fee of the structural design changes has been developed in this research based on designing various type and complexity of low rise RC buildings. The developed method has been verified by a panel of experts by means of questionnaire survey and found to be practical, suitable and effective. Set of guidelines for improving consultancy design documents with respect to design changes and another set of guidelines for managing their claims have been also developed. These guidelines have been validated by panel of experts using Delphi technique. The result of the validation process provides encouragement to recommend the guidelines for practical implementation.

ABSTRAK

Perubahan terhadap rekabentuk asal bagi pembinaan bangunan konkrit bertetulang (RC) sering berlaku dan isu ini telah sekian lama diperbahaskan. Ia juga sering menjadi punca perbalahan dalam industri pembinaan. Walaupun perubahan dalam rekabentuk dalam keadaan tertentu adalah perlu dilakukan tetapi kesan negatif akibat daripada perubahan yang dibuat juga turut mebimbangkan pihak yang terlibat seperti klien, jurutera perunding dan kontraktor. Perubahan terhadap rekabentuk bukan sahaja meninggalkan kesan terhadap kredebilitinya rekabentuk itu sendiri malah boleh mendorong kepada berlakunya perbalahan kontrak disebabkan oleh kelewatan kerja dan perubahan kos akibat daripada perubahan daripada skop asal kerja. Lazimnya kaedah penilain terhadap perubahan kos bagi kerja pembinaan akibat daripada perubahan skop kerja agak jelas mengikut peruntukan yang sedia ada didalam kontrak pembinaan. Walaubagaimana pun kaedah penialaian kos terhadap perubahan bagi kerja merebentuk tidak begitu mendapat perhatian para penyelidik. Oleh itu kajian ini telah dijalankan untuk mengenalpasti masaalah ini dengan lebih mendalam serta mengemukakan suatu kaedah alternatif bagi menilai kos perubahan bagi mengubahsuai rekabentuk asal yang dilaksanakan oleh pihak perunding. Pada peringkat awal kajian ini tela mengenalpasti punca, kesan dan kaedah penialain kos dalam proses membuat perubahan terhadap rekabentuk bagi sesabuah bangunan konkrit. Juga dikaji adalah kaedah yang boleh digunakan untuk mengurangkan keperluan membuat prubahan rekabentuk oleh pihak klien. Kaedah penyelidikan yang digunakan termasuklah sesi temubual, kajian kes dan menghantar borang soal selidik kepada responden. Kaedah analisa frekuensi dan kaedas Statistik Tak Berparametar telah digunakan untuk membuat analisa data kualitatif dan kuantitatif yang digunakan dalam penyelidikan ini. Hasil dari kajian mendapati bahawa perubahan terhadap rekabentuk adalah sesuatu yang lazim berlaku dan dalam banyak kes menyebabkan berlakunya tuntutan tambahan yang berlebihan yang dibuat oleh perunding akibat daripada tidak ada kaedah yang sesuai untuk membuat penialaian kos yang praktikal dan wajar digunakan. Lanjutan dari itu hasil dari penyelidikan ini telah membangunkan satu kaedah yang sesuai digunakan untuk sebagai kaedah alternatif untuk membuat penialaian apabila berlakunya perubahan atau pengubahsuaian terhadap rekabentuk asal terhadap struktur bangunan konkrit bertetulang sederhana tinggi. Kaedah ini telah dipersetujui sebagai sesuai digunakan oleh panel para professional yang mempunyai pengalaman yang luas dalam industri pembinaan di Oman. Selain dari itu penyelidikan ini turut membangunkan satu garispanduan yang sesuai diterapkan dalam kontrak untuk mengemaskini lagi proses membuat perubahan rekabentuk dan menguruskan tuntutan yang dibuat berkaitan dengan perubahan yang dibuat tersebut. Garispanduan ini telah dibuat pengesahan dengan panel yang berpengalaman dalam industri pembinaan di Oman dengan menggunakan kaedah Delphi.

vii

TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION OF THE STATUS OF THESIS

SUPERVISORS' DECLARATIONS

TITLE PAGE i

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES xiv

LIST OF FIGURES xix

LIST OF SYMBOLS xxii

LIST OF APPENDICES xxiii

1 INTRODUCTION 1

1.1 Background and Rationale 1

1.2 Problem Statement 4

1.3 Aim and Objectives 5

1.4 Scope and Limitations of the Research 6

1.5 Brief Research Methodology 7

1.6 Justification of the Research 7

1.7 Significance of the Study 10

1.8 Research Contributions 10

1.9 Organization of the Thesis 10

viii

2 DESIGN CHANGES 14

2.1 Introduction 14

2.2 Definitions of Design Changes 14

2.3 Classifications of Design Changes 15

2.4 Sources of Design Changes 17

2.5 Causes of Design Changes 20

2.6 Impact of Design Changes 28

2.6.1 Impact of Design Changes on Cost 31

2.6.2 Impact of Design Changes on Time 34

2.6.3 Impact of Design Changes on Productivity 36

2.7 Development for Improving the Management of 41 Design Changes

2.8 Chapter Summary 45

3 THE PRINCIPLE OF CONSULTING 48 ENGINEERING PRACTICE

3.1 Introduction 48

3.2 Definition of the Client 49

3.3 Definition of the Consulting Engineer 49

3.4 Reasons for Consulting Engineering Services 50

3.5 Services Provided by Consulting Engineers 52

3.5.1 Feasibility Study Phase 53

3.5.2 Preliminary Design Phase 53

3.5.3 Detailed Design Phase 54

3.5.4 Tender Stage 54

3.5.5 Supervision Phase 55

3.5.6 Operation Phase 56

3.6 Methods of Charging for Consulting Services 57

3.6.1 Lump Sum Method 58

3.6.2 Salary Cost Times Multiplier Plus 59 Non-Salary Cost method

3.6.3 Cost plus Fixed Amount Method 59

3.6.4 Per Diem Method 60

3.6.5 Percentage of Construction Cost 61

3.6.6 Retainer Method 64

ix

3.7 Chapter Summary 64

4 THE CONSTRUCTION INDUSTRY IN OMAN 66

4.1 Introduction 66

4.2 Oman at a Glance 67

4.3 Brief Highlights on Oman Economy 67

4.4 The Construction Sector in Oman 68

4.5 Consulting Engineering Services in Oman 71

4.6 Typical Scope of Consultant Services in 71 Omani Standards

4.7 Fee Assessment of the Design Changes in 75 Omani Standard

4.8 Chapter Summary 76

5 RESEARCH METHODOLOGY 78

5.1 Introduction 78

5.2 Literature Review 79

5.3 Interviews with Professionals 80

5.4 Case Studies 81

5.5 Questionnaire Survey 82

5.5.1 Design of the Questionnaire 83

5.5.2 Pilot Survey 85

5.5.3 Main Survey Questionnaire 85

5.5.4 The Population and the Distribution of the 86 Questionnaire Survey

5.5.5 Methods of Analysing the Questionnaire Survey 88

5.6 Methodology for Development of an Alternative 92 Method to Assess the Fee of Structural Design Changes

5.6.1 Design Parameters and Assumption for the 95 Building Design

5.6.2 Details and Classifications of the 95 Selected Buildings

5.6.3 Source of the Structural Design of the Buildings 96

5.6.4 General Structural System for the 97 Buildings of this Study

x

5.6.5 The Principle of the Adopted Structural Design 97

5.7 Questionnaire for Validating the Developed Method 99

5.7.1 Design of the Questionnaire 99

5.8 Development of the Guidelines 100

5.9 The Method of Validating the Developed Guidelines 102

5.9.1 Background of the Delphi Method 102

5.9.2 Selection of the Professionals for the 104 Delphi Questionnaires

5.9.3 Identifying the Number of Professionals for the 105 Delphi Method

5.9.4 Identifying the Number of Rounds for the 105 Delphi Method

5.9.5 Format of the Delphi Rounds for this Research 106

5.10 Chapter Summary 106

6 DATA COLLECTION 108

6.1 Introduction 108

6.2 Interviews with Professionals 109

6.2.1 Discussions of the Interviews’ Results 109

6.2.2 The Occurrence of Design Changes 109

6.2.3 The Causes and Sources of Design Changes 118

6.2.4 The Impact of Design Changes 119

6.2.5 Existing Methods for Assessing the Fee of 119 Design Changes and their Limitations

6.3 Case Studies Results 121

6.3.1 Case Study One 121

6.3.2 Case Study Two 123

6.3.3 Case Study Three 125

6.3.4 Causes of Design Changes 126

6.3.5 Sources of Design Changes 128

6.3.6 Impact of Design Changes on Cost 129

6.3.7 Impact of Design Change on Schedule 130

6.3.8 Existing Methods for Assessing the 131 Structural Design Changes

6.4 Questionnaire Survey Result 132

xi

6.4.1 Causes of Design Change Due to Clients 132

6.4.2 Causes of Design Change Due to Consultants 135

6.4.3 Causes of Design Change Due to Contractors 137

6.4.4 Sources of Design Changes 139

6.4.5 Impacts of Design Change 141

6.4.6 Corrective Actions and Preventive 144 Measures to Minimize the Avoidable

Design Changes

6.4.7 Preferences of Using the Existing 149 Methods for Assessing the Fee of Design Changes

6.4.8 Limitations of the Existing Methods 150

6.4.8.1 Limitations of the Man-Hours Method 151

6.4.8.2 Limitations of the Percentage of 153 Construction Method

6.4.8.3 Limitations of the Area Unit Rate Method 154

6.4.8.4 Limitations of the Lump-Sum Method 157

6.5 Chapter Summary 158

7 DEVELOPMENT OF THE PROPOSED METHOD 160 TO ASSESS THE FEE OF THE STRUCTURAL DESIGN CHANGES IN RC BUIDLINGS

7.1 Introduction 160

7.2 Preliminary Structural Design Phase 161

7.2.1 Locations of the Structural Members 161

7.2.2 Load Calculations 162

7.2.3 Sizing the Structural Members 163

7.2.4 Miscellaneous Structural Elements 166

7.3 Detailed Structural Design Phase 166

7.4 Preliminary Structural Drafting Phase 168

7.5 Detailed Structural Drafting Phase 170

7.6 General Approach for Developing the Proposed Method 170

7.7 Design by Manual Method 172

7.7.1 Preliminary Design and Drafting for 172 One Floor Buildings

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7.7.2 Detailed Design and Drafting for 176 One Floor Buildings

7.7.3 Preliminary Design and Drafting for 181 Two Floors Buildings

7.7.4 Detailed Design and Drafting for 185 Two Floors Buildings

7.7.5 Preliminary Design and Drafting for 189 Three Floors Buildings

7.7.6 Detailed Design and Drafting for 194 Three Floors Buildings

7.7.7 Preliminary Design and Drafting for 197 Four Floors Buildings

7.7.8 Detailed Design and Drafting for 202 Four Floors Buildings

7.7.9 Comparison of the Preliminary Design for 205 the Four Types Buildings

7.7.10 Comparison of the Detailed Design for 206 the Four Types Buildings

7.7.11 Comparison between the Preliminary and 208 Detailed Design

7.8 Design Based on STAAD Pro. Software 210

7.8.1 Preliminary Design and Drafting by 211 STAAD Pro for One Floor Buildings

7.8.2 Detailed Design and Drafting by 216 STAAD Pro for One Floor Buildings

7.8.3 Preliminary Design and Drafting by 220 STAAD Pro for Two Floors Buildings

7.8.4 Detailed Design and Drafting by 224 STAAD Pro for Two Floors Buildings

7.9 Suggested Method for Assessing the Fee of the 228 Structural Design Changes

7.10 Illustration for Using the Proposed Method 231

7.10.1 Example 1, One Floor Building 231

7.10.2 Example 2, Two Floors Building 234

7.11 The Result of the Validation 238

7.12 Chapter Summary 240

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8 DEVELOPMENT OF THE GUIDELINES 242 FOR MANAGING DESIGN CHANGES

8.1 Introduction 242

8.2 Initial List of Guidelines for Improving Consultancy 242 Design Documents

8.3 Initial List of Guidelines for Managing the Claims of 245 Design Changes

8.4 Validation of the Developed Guidelines 246

8.5 The Delphi Round One Questionnaire 247

8.5.1 The Result of the Delphi Round One 247 Questionnaire

8.6 The Delphi Round Two Questionnaire 248

8.6.1 The Result of the Delphi Round Two 248 Questionnaire

8.7 The Delphi Round Three Questionnaire 252

8.7.1 The Result of the Delphi Round Three 253 Questionnaire

8.8 Chapter Summary 254

9 CONCLUSIONS AND RECOMMENDATIONS 245

9.1 Introduction 255

9.2 Conclusions 256

9.3 Contributions of the Research 263

9.4 Suggestions for Further Research 263

REFERENCES 265

Appendices A - G 277 - 353

xiv

LIST OF TABLES

TABLE NO. TITLE PAGE

2.1 Actual Causes of Changes in the UK 18 2.2 Importance Indexes of Sources of 19

Changes in Saudi Arabia 2.3 Sources of Changes, In Botswana, Gabrone 20 2.4 Causes of Changes in Hong Kong Building Projects 24 2.5 Causes of Changes in Botswana 27 2.6 Effects of Changes on Projects 30 2.7 Project Size and Changes Measurer 32 2.8 Causes and Cost of Changes 34 2.9 Quantitative Effect of Disruptions 38 3.1 Converted Building Scale for Structural Works 63 in Buildings Expressed As A % of Building Cost 4.1 No. of Building Permits, Estimated Cost and Type of Building 70 4.2 Consulting Firms Grades 72 5.1 Ranking System for the Questionnaire of this Study 89

using Likert (Ordinal) Scale 5.2 Basic Buildings Details 96 6.1 Result of the Interviews with Consultants 110 6.2 Result of the Interviews with Contractors 112 6.3 Result of the Interviews with Clients 114

xv

6.4 Result of the Interviews – Comparisons of Respondents 116 6.5 Case Study One - Causes, Sources and Fee of Changes 122 6.6 Case Study Two - Causes, Sources and Fee of 124

Design Changes 6.7 Case Study Three - Causes, Sources and Fee of 127

Design Changes 6.8 Case Studies - Impact on Cost 130

6.9 Case Studies - Impact on Schedule 131 6.10 Main Scores (MS) and Ranks (R) for Causes of 133

Design Changes Due to Clients

6.11 Test for Agreement on the Ranking for Causes of 134 Design Changes Due to Clients

6.12 Main Scores (MS) and Ranks (R) for Causes of 136 Design Changes Due to Consultants

6.13 Test for Agreement on the Ranking for Causes of 137 Design Changes Due to Consultants

6.14 Main Scores (MS) and Ranks (R) for Causes of 139 Design Changes Due to Contractors

6.15 Test for Agreement on the Ranking for Causes of 139 Design Changes Due to Contractors

6.16 Main Scores (MS) and Ranks (R) for Sources 140

of Design Changes 6.17 Test for Agreement on the Ranking for Sources 141

of Design Changes 6.18 Main Scores (MS) and Ranks (R) for Impacts 142

of Design Changes 6.19 Test for Agreement on the Ranking for Impacts 143

of Design Changes 6.20 Main Scores (MS) and Ranks (R) for Corrective 145

Actions and Preventive Measures to Minimize the Avoidable Design Changes

xvi

6.21 Test for Agreement on the Ranking for 149 Corrective Actions and/or Preventive Measures to Minimize the Avoidable Design Changes

6.22 Main Scores (MS) and Ranks (R) for Preference 150

of Existing Methods for Assessing the Fee of Design Changes

6.23 Main Scores (MS) and Ranks (R) for 151

Limitation(s) of the Man-Hours Method 6.24 Main Scores (MS) and Ranks (R) for Limitation(s) 153

of the Percentage of Construction Cost Method 6.25 Main Scores (MS) and Ranks (R) for 155

Limitation(s) of the Area Unit Rate Method 6.26 Main Scores (MS) and Ranks (R) for 157

Limitation(s) of the Lump-Sum Method 7.1 Times, in Minutes, and Percentage of Time for 172

Preliminary Structural Design (One Floor Buildings) 7.2 Times, in Minutes, and Percentage of Time for 173 Preliminary Structural Drafting (One Floor Buildings) 7.3 Percentage of Time for Preliminary Structural 174

Design and Drafting (One Floor Buildings) 7.4 Times, in Minutes, and Percentage of Time for 177

Detailed Structural Design (One Floor Buildings) 7.5 Times, in Minutes, and Percentage of Time for 178

Detailed Structural Drafting (One Floor Buildings) 7.6 Percentage of Time for Detailed Structural 179

Design and Drafting (One Floor Buildings) 7.7 Times, in Minutes, and Percentage of Time for 182

Preliminary Structural Design (Two Floors Buildings) 7.8 Times, in Minutes, and Percentage of Time for 183

Preliminary Structural Drafting (Two Floors Buildings) 7.9 Percentage of Time for Preliminary Structural 184 Design and Drafting (Two Floors Buildings) 7.10 Time, in Minutes, and Percentage of Time 186

For Detailed Structural Design (Two Floors Buildings)

xvii

7.11 Time, in Minutes, and Percentage of Time 187 for Detailed Structural Drafting (Two Floors Buildings)

7.12 Percentage of Time for Detailed Structural 188

Design and Drafting (Two Floors Buildings) 7.13 Times, in Minutes, and Percentage of Time for 190

Preliminary Structural Design (Three Floors Buildings) 7.14 Times, in Minutes, and Percentage of Time for 191

Preliminary Structural Drafting (Three Floors Buildings) 7.15 Percentage of Time for Preliminary Structural 192

Design and Drafting (Three Floors Buildings) 7.16 Times, in Minutes, and Percentage of Time for 194 Detailed Structural Design (Three Floors Buildings) 7.17 Times, in Minutes, and Percentage of Time for 195

Detailed Structural Drafting (Three Floors Buildings) 7.18 Percentage of Time for Detailed Structural Design and 196

Drafting (Three Floors Buildings) 7.19 Times, in Minutes, and Percentage of Time for 198

Preliminary Structural Design (Four Floors Buildings) 7.20 Times, in Minutes, and Percentage of Time for 199

Preliminary Structural Drafting (Four Floors Buildings) 7.21 Percentage of Time for Preliminary Structural Design 200

and Drafting (Four Floors Buildings) 7.22 Times, in Minutes, and Percentage of Time for Detailed 202

Structural Design (Four Floors Buildings) 7.23 Times, in Minutes, and Percentage of Time for Detailed 203

Structural Drafting (Four Floors Buildings) 7.24 Percentage of Time for Detailed Structural Design 204

and Drafting (Four Floors Buildings) 7.25 Time, in Minutes, and Percentage of Time for 208

Preliminary and Detailed Structural Design and Drafting 7.26 Times, in Minutes, and Percentage of Time for 212

Preliminary Structural Design based on STAAD Pro Design Software (One Floor Buildings)

xviii

7.27 Percentage of Time for Preliminary Structural Design 213 and Drafting Based on STAAD Pro Design Software (One Floor Buildings)

7.28 Times, in Minutes, and Percentage of Time for Detailed 216

Structural Design based on STAAD Pro Design Software (One Floor Buildings)

7.29 Percentage of Time for Detailed Structural Design 217

and Drafting based on STAAD Pro Design Software (One Floor Buildings)

7.30 Times, in Minutes, and Percentage of Time for Preliminary 220

Structural Design based on STAAD Pro Design Software (Two Floors Buildings)

7.31 Percentage of Time for Preliminary Structural Design 221

and Drafting based on STAAD Pro Design Software (Two Floors Buildings)

7.32 Times, in Minutes, and Percentage of Time for Detailed 224

Structural Design based on STAAD Pro Design Software (Two Floors Buildings)

7.33 Percentage of Time for Detailed Structural Design 225

and Drafting based on STADD Pro Design Software (Two Floors Buildings)

7.34 Percentage of Time for Preliminary Structural Design 229

and Drafting (One Floor to Four Floors Buildings) 7.35 Percentage of Time for Detailed Structural Design 230

and Drafting (One Floor to Four Floors Buildings) 7.36 Questionnaire Result for the Validation of the POF Method 239 8.1 Delphi Round Two Results: Relative Importance 249

Level of each Guideline for Improving the Consultancy Design Documents

8.2 Delphi Round Two Results: Relative Importance 251 Level of each Guideline for the Claims of the Design Changes

xix

LIST OF FIGURES

FIGURE NO. TITLE PAGE 1.1 Research Methodology Flow Chart 8 2.1 Causes of Changes in Hong Kong 25 2.2 Planned and Actual Loading Curves 36 2.3 Effects of Change within Phase 39 2.4 Construction Change and Construction Productivity 39 2.5 Design Change and Design Productivity 40 3.1 Stages in Projects’ Design Cycle 52 3.2 Median Basic Fees as a Percentage of Net 62

Construction Cost 5.1 Type of Organization Represented 87 5.2 Distribution Profiles of Work Experience of the 88

Three Groups of Survey Respondents 7.1 Percentages of Time for the One Floor Buildings 176

at Preliminary Design Stage based on Manual Method 7.2 Percentages of Time for the One Floor Buildings at 181

Detailed Design Stage based on Manual Method 7.3 Percentages of Time for the Two Floors Buildings 185

at Preliminary Design Stage based on Manual Method 7.4 Percentages of Time for the Two Floors Buildings at 189

Detailed Design Stage based on Manual Method 7.5 Comparison between the Estimated Percentages of 193

Time to Design Main Structural Members for the Three Buildings of Three Floors each at Preliminary Design Stage

xx

7.6 Comparison between the Estimated Percentages of 197 Time to Design Main Structural Members for the Three Buildings of Three Floors each at Detailed Design Stage

7.7 Comparison between the Estimated Percentages of Time 201

to Design Main Structural Members for the Three Buildings of Four Floors each at Preliminary Design Stage

7.8 Comparison between the Estimated Percentages of Time 205

to Design Main Structural Members for the Three Buildings of Four Floors each at Detailed Design Stage

7.9 Comparisons between Percentages of Time to Design 206

Main Structural Members for the Four Buildings at Preliminary Design Stage

7.10 Comparisons between Percentages of Time to Design 207

Main Structural Members for the Four Buildings at Detailed Design Stage

7.11 Comparison between Percentages of Time for 209

Preliminary and Detailed Design Stages 7.12 Percentages of Time for the One Floor Buildings at 214

Preliminary Design Stage based on STAAD Pro Design Software

7.13 Comparison between Manual Design Vs. STAAD Pro 215

Design Software for One Floor Buildings at Preliminary Design Stage

7.14 Percentages of Time for the One Floor Buildings 218

at Detailed Design Stage based on STAAD Pro Design Software

7.15 Comparison between Manual Design Vs. STAAD Pro 219

Design Software for the Three Buildings of One Floor each at Detailed Design Stage

7.16 Percentages of Time for the Two Floors each 222

at Preliminary Design Stage based on STAAD Pro Design Software

7.17 Comparison between Manual Design Vs. STAAD Pro 223

Design Software for the Three Buildings of Two Floors each at Preliminary Design Stage

7.18 Percentages of Time for the Two Floors Buildings 226

at Detailed Design Stage based on STAAD Pro Design Software

xxi

7.19 Comparison between Manual Design Vs. STAAD Pro 227 Design Software for the Three Buildings of Two Floors each at Detailed Design Stage

7.20 Original Plinth (Ground) Beams Plan 232 7.21 Modified Plinth (Ground) Beams Plan 232 7.22 Original Roof Slabs/Beams Plan 233 7.23 Modified Roof Slabs/Beams Plan 233 7.24 Original Ground Floor Roof Slabs/Beams Plan 235 7.25 Modified Ground Floor Roof Slabs/Beams Plan 235 7.26 Original First Floor Roof Slabs/Beams Plan 236 7.27 Modified First Floor Roof Slabs/Beams Plan 236

xxii

LIST OF SYMBOLS

di - The different between the rank given by one group and the rank given by another group f - frequency of responses to each score for each factor fn - Total number of factors ranked by any two groups for any given category OCC - Original Contract Fee MS - Mean Score N - Number of responses Nf - total number of responses NMM - Number of the Modified structural Members TNM - Total Number of the structural Members S - Score given to each factor as ranked by the respondents

xxiii

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Extract from Standard Form of Agreement and 277 Conditions for Consultancy Services for Building and Civil Engineering Works (1987)

B Questionnaire Survey – Second Stage 284 C Architectural Plans and Elevations 296 D Typical Structural Design and Detail 321 E Questionnaire for Validating the POF Method 330 F Round One Delphi Questionnaire Survey 340 G Round Three Delphi Questionnaire Survey 346

CHAPTER 1

INTRODUCTION

1.1 Background and Rationale

Engineering design changes and their consultancy design fee assessment for

reinforced concrete buildings’ design have, for long time, been a topic of prolonged

discussions and frequent disputes between clients and their appointed consulting

engineers. Design changes in their simple term are defined as any addition, omission

or modification to the original scope of work in which a contract was signed

(Akinsola et al., 1997) or an adjustment to the completed design that may leads to

change the original contract design fee (Baxendale and Schofield, 1996). These

design changes might have great effect especially on cost and time and are likely to

be a cause of claims and disruptions. In general, consulting engineers provide the

necessary effort to develop the concept of the design to fulfil the intended use of the

projects under design to their client’s requirements. An approval to preliminary

design principle sets the basis for subsequent detailed design and for production of

technical specification and construction documents.

It is common in the construction industry for almost all projects to go through

various degrees of modifications at the design stage and more commonly during the

construction. These changes are mostly caused by clients, in favour of getting new

ideas or cost reduction on projects (Federal Construction Council, 1983; Kelvin,

1996). Design members have been also the main contributors of the design changes

in the construction industry. They originate the changes to rectify their mistakes and

2

to improve or optimize their design (Hibberd, 1982; Choy and Sidwell, 1991).

Contractors may also introduce changes to adopt alternative construction methods

that are of more familiarity (McDermott and Dodd, 1984; Yogeswaran, 1998) and

suppliers, in order to meet the manufacturer’s recommendation to use a specific

material (Emmitt, 2001).

The most common reasons that necessitate design changes are financial

(Ssegawa, et al. 2003), clients’ new requirements (Wilson, 1982), coordination

problems (Bubshait et al., 1998), unclear scope of work (Austin et al., 2002), design

errors (Leonard, et al., 1988), unexpected site conditions (Essex, 1996) and

insufficient design information at the design stage (Ogunlana, et al., 1996). The

possible changes could be minor related to design development which have no or

relatively low cost effect on overall agreed design fees and could be major related to

new ideas or changing the principle of the original design which, in turn, required re-

planning and re-designing that leads to a major cost effect.

There are numerous impact caused by design changes that influence the

outcome of a project. Any inferior assessment, determination, misunderstanding or

unavailability of relevant information or knowledge during the design stage leads

inevitably to less than an optimum design that can be unnecessarily expensive and

difficult to correct/alter at later stages of a project life cycle (Hashimoto, 1993). A

successful project means that the project has met the required quality level,

completed on time and within the allocated budget (Chan and Kumaraswamy, 1994;

Frimpong et al. 2003). Design changes usually divert these fundamental aims in the

construction industry. These changes lead to great disruption on design and

construction activities which, in turn, increase the chances for errors, increase cost,

delay and decrease productivity.

Although design changes in many cases are essential for, as example, design

development; clients, consulting engineers and contractors all have become

increasingly worried about their magnitude and their impact that are associated with

them. Design changes do not only affect the reliability of the design but also

increase the possibility of contractual disputes due to the unpredictable delay and

cost overrun on the original scope of work. The three case studies that have been

3

carried out from the construction industry in the Sultanate of Oman and were part of

this research investigation have shown that the engineering consultancy fee can be as

high as 189.8 percent of the original fee and the engineering consultancy time can

increase by 195 percent.

While the cost of modifying the construction scopes is well defined in normal

contract documents, the fee of engineering changes is yet to receive more attention.

Clients are not always willing to accept the variation charges set by consulting

engineers mainly because they feel they are unjustifiable and consultants, on the

other hand, feel that clients unreasonably reject or reduce the claimed amount. This

can be predicted to some extend since the design changes are not easily quantified.

They are various methods in which consulting engineers have been using to

assess the consultancy design fee associated with design changes These methods

have been identified from the result of the interviews with the professionals working

in the construction industry, from the case studies and from the questionnaire that all

were carried out at the initial stage for this research work. These methods are the

Man-Hours method, Percentage of Construction Cost method, Area Unit Rate

method and the Lump-Sun method. However the result of the interviews with the

professionals working in the construction industry; the case studies; and the

questionnaire survey that have been conducted as part of this research revealed that

each one of these methods has various degrees of difficulties and limitations for

implementation to the point where it becomes unpractical to adopt anyone of them.

To avoid the possible disputes arising from the lack of an affective way to evaluate

the engineering consultancy fee of design changes, there is a need to develop a

practical method for fee assessment of the structural design changes when they arise.

The primary aim of this research work is to develop an alternative method for

assessing the consultancy design fee as a result of modifying the original structural

design; to highlight suggestions for minimizing the avoidable design changes; and to

provide guidelines for improving the consultancy design documents with respect of

managing design changes

4

1.2 Problem Statement

Many articles have been written on the general subject of design changes.

Much of that research have focused on their nature and extend such as causes,

sources and impacts, where others have concentrated on their legal aspects such as

claims and disputes. Although design changes in many cases are essential for, as

examples, design developments, design improvements, rectification of mistakes and

resolution of problems related to unexpected circumstances, nevertheless, clients,

consulting engineers and contractors all have become increasingly worried about the

negative parts that are associated with design changes, and the poor recovery of the

actual fee associated with their settlements (Jergeas and Hartman, 1994).

Nevertheless, design changes are still an ongoing problem that continues to raise the

concerns in the construction industry. Such concerns stimulated this research and

others to produce a series of reports, for example Latham report (1994) where

variations have been identified as one of the main problems challenging the

construction industry.

Almost all projects go through different level of modifications not only at the

design stage but also during the construction. Previous studies such as the one by

Anderson and Tucker (1994) reveals that about one third of architectural/engineering

projects missed cost and schedule targets as a result of design changes. Burati et al.

(1992) have shown that design changes increased the construction cost by an average

amount of 12.4 percent of the total cost of the projects in the United Kingdom.

Chang (2002) reported that an engineering consultancy fee increased on an average

of 24.8 percent based on four sampled projects in Taiwan as a result of design

changes.

Delays have been identified as a key factor that increase the construction cost

of the projects worldwide (Kartam, 1999). Design changes are one of the main

causes that lead to such construction delays. Arditi et al. (1985) found that 3.54

percent of the delays in public projects in Turkey were caused by design changes. In

the UK, 49 percent of the delays are caused by factors related to design changes

(Sullivan and Harris, 1986). In Nigeria, this percentage is reported to be as high as

71 percent (Okpala and Aniekwu, 1988).

5

Consulting engineers are familiar with the methods of pricing their

consultancy design services at the tender stage. These methods are well developed

and well documented as it will be seen in the next chapter. When changes are

introduced, there is a lack of an affective method to assess their fee. Normally

consulting engineers either estimate their extra design fee for modifying the original

design in a lump-sum basis or alternatively predict the most likely man-hours that are

needed to carry out the change; or keep record of the man-hours they spend to

execute the changes. The consulting engineers then submit the man-hours to their

clients for payments. Clients, on the other hand, do not always accept the submitted

man-hours because they feel the man-hours are overestimated due to lack of trust. At

the same time, there is no well accepted alternative methods that might be used to

quantify the design changes and hence to assess their fee. Such situations may

increase the possibility of contractual disputes, affect the relationships and lead to

dissatisfaction and disappointment to both the clients and the consulting engineers.

Recognizing these facts, there is an obvious need for in depth study to address these

issues and to find a practical solution that might be used to assess the fee of

modifying the original design changes. This research is a step toward satisfying this

need.

1.3 Aim and Objectives

It is a well known fact that many design changes are most likely inevitable

during the life cycle of the projects. These changes might be minor so that no major

claims on fee or time extension takes place or might be major in which it results in

main claims. While the original consultancy design fee is normally stated in the

contract documents based on the tender submission and negotiation, there is no

practical and acceptable method yet to assess the fee of modifying the original

design. The primary aim of this research work is to formulate practical procedures

for the assessment of the structural design changes so that an enhancement can be

made to the existing practice. The result of this study will put forward practical

means of avoiding and resolving the disputes caused by the lack of appropriate

method of assessing the fee of design changes.

6

The review and investigation of this research work are to be carried out with

the following objectives:

(1) To identify the sources, the causes, and the impacts of the design changes on reinforced concrete buildings;

(2) To establish corrective actions and preventive measures to minimise the

avoidable design changes; (3) To identify and evaluate the various methods for assessing the fee of the

structural design changes and to identify their limitations; (4) To develop an alternative method to assess the fee of the structural

design changes for low rise RCC buildings; (5) To develop guidelines to improve the consultancy design documents; and

(6) To develop guidelines to manage the design changes when they occur

1.4 Scope and Limitations of the Research

In this study, the proposed method for assessing the fee of the structural

design changes is based on designing 12 number small scale low rise reinforced

concrete buildings consisting of one floor to four floors. These buildings have

already been constructed in the Sultanate of Oman prior to this study. The buildings

under this research work have been designed using both manual calculations and

STAAD Pro 2003 software and have been drafted by AutoCAD 2000 software. The

investigation and the scopes of this study were carried out in the Sultanate of Oman

and hence limited to the typical standard details and normal practice in the country.

The finding can only be applied to these types of projects.

7

1.5 Brief Research Methodology

Research methodology provides a general plan and necessary steps to execute

the research in a scientific manner. It is a logical model for collecting the

information, analysing the data and interpreting the findings of the research. It is also

the necessary methods that lead to achieve the aim and the objectives of the research.

To this end, Figure 1.1 outlines a flow chart for the methodology of this research. A

more detailed research methodology is discussed in Chapter 5.

1.6 Justification of the Research

The idea of this work came from the past experience and knowledge on the

extent of the problems and the size of the claims associated with the structural design

changes. In many cases, design changes lead to disputes due to lack of proper

guidelines to manage them and lack of appropriate methods on their fee variation

assessment. The topic went through progressive refinement taken into consideration

the interest in the area of the study, findings of previous works as well as the

professional opinion from the industry in order to explore areas of dissatisfaction.

As a result of this initial investigation, the topic of this research is advanced to the

state that it is delineated sufficiently for the aim and objectives of the research and

importantly to make significant contribution to the subject.

8

Establishing the Aim

Identifying the Problem

Identifying the Objectives

Identifying the Impact of Design

Changes

Identifying up to Date Development

for Managing Design Changes

Identifying the Sources and Causes of Design Changes

Identifying the Existing Methods for Assessing the Fee of Design Changes and their Limitations

Verifying the Sources, Causes and Impacts of

Design Changes

INITIATION OF THE RESEARCH

INTERVIEWS WITH PROFESSIONALS

CASE STUDIES

Giving Actual Examples on the Size and Effect of

Design Changes

Demonstrating the Limitations of the Existing

Methods in the Practice

LITERATURE REVIEW

Cont.

Figure 1.1 : Research Methodology Flow Chart

9

Establishing the Important Level of the Sources, Causes

and Impacts of Design Changes

Identifying the Limitations of the

Existing Methods for Assessing the Fee of

Design Changes

BUILDINGS DESIGN MANUALLY AND BY STAAD PRO SOFTWARE AND DRAFTING BY

AUTOCAD FOR DEVELOPING AN ALTERNATIVE METHOD FOR ASSESSING

THE FEE OF DESIGN CHANGES

VALIDATION OF THE DEVELOPED METHOD BY QUESTIONNAIRE

SURVEY

CONCLUSIONS, RECOMMENDATIONS AND

SUGGESTIONS FOR FUTURE RESEARCH

QUESTIONNAIRE SURVEY

Identifying the Possible Preventive

Measures to Minimise Design

Changes

DEVELOPMENT OF GUIDELINES FOR MANAGING DESIGN CHANGES

VALIDATION OF THE DEVELOPED GUIDELINES BY DELPHI METHOD

PILOT STUDY

Figure 1.1 : Research Methodology Flow Chart (Continue)

10

1.7 Significance of the Study

The study is unique in the sense that no previous attempts have been made on

the subject in spite of wide spread dissatisfaction associated with design changes,

their impact and their fee assessment on reinforced concrete buildings. Surely it will

improve the industry’s understanding on the negative aspects that are related to

design changes and help to reduce the possible disputes in this regard. The study

will improve the efficiency, effectiveness and satisfaction in the construction practice

and it will make a contribution to the construction industry in general and especially

to the consulting engineering firms by developing a practical method of charging for

design changes. The study will help define the related issues and directions that need

to be addressed in the future.

1.8 Research Contributions

The main contribution of this study to the body of knowledge falls on the

following aspects: Firstly, the study gives emphasis on identifying the sources,

causes and impacts of design changes on reinforced concrete buildings as well as on

establishing corrective actions and/or preventive measures to minimise the avoidable

ones. This study has developed practical and reliable method for fee variation

assessment that might be implemented by professionals to assess the fee of changing

or modifying the original design of reinforced concrete buildings. In addition, it is

anticipated that the study will provide set of guidelines to improve the current design

contract documents with respect to design changes and another set of guidelines to

manage their claims

1.9 Organization of the Thesis

This thesis comprises four major components which can be summarized as

follows:

11

• Providing background, identifying the problems of design changes and reviewing

their associated issues through literature searching;

• Investigating and validating the main topics related to this research work through

interviews with the professionals working in the construction industry, case

studies and a questionnaire survey;

• Making a contribution to the body of knowledge by developing an alternative

method to assess the fee of the structural design change when they occur; and

• Providing practical guidelines to manage design changes.

The four main components of the research are presented in nine chapters and

are briefly described as follow:

Chapter 1 introduces the background of the research, its aim and objectives. It also

discusses the brief research methodology used; the research justification; the

significant of the study; the contributions; the scope of the research and a brief

summary on the structure of the thesis.

Chapter 2 presents the findings from the literature review. It focuses on the issues

of design changes which include the following:

• definitions and classifications of the design changes;

• sources, causes and impacts of the design changes; and

• new developments for managing design changes

Chapter 3 focuses on the discussion related to the principle of consulting

engineering practice. The emphasis is given to these issues:

• the definitions of the clients and the consulting engineers

• the reasons for consulting engineering services

• the services provided by the consulting engineers

12

• the method of charging for consulting engineering services

Chapter 4 presents an overview of the construction industry in the Sultanate of

Oman from which the majority of the data for this study has been carried out. It

gives basic information about Oman as a country; brief highlights on Omani

economy; the construction sector in Oman and the consulting engineering services in

the country.

Chapter 5 discusses the methodology adopted for this research. It starts by

discussing the method used to justify the need for this research through the

interviews with the professionals, case studies and questionnaire survey. Then it

discusses the method used for data collection. An explanation was given to each

method in term of their relation to the study, selection criteria and the anticipated

result of each method.

Chapter 6 presents the data collection for the initial investigation to establish the

extent of the problems associated with design changes and to justify the need for this

research as perceived by the professionals in the industry. Interviews with

professionals, three case studies and two stages questionnaire survey have been

conducted and their results were presented in this chapter. In the interviews and in

the case studies, the main problems of design changes have been identified as well as

their causes, sources and impacts on the projects. From the results of the

questionnaire survey, the significant level of the causes, sources and impacts of

design change were identified along with the possible corrective measures to

minimise them. The limitations of the existing methods are presented in this chapter

as well.

Chapter 7 presents the development of the proposed method to assess the fee of the

structural design changes in RCC buildings. It starts by highlighting the general

approach that has been adopted for generating the data. The results have been shown

in tables and illustrated graphically for comparisons. From the obtained data, a

method for assessing the fee of the structural design changes has been developed.

Practical examples to illustrate the use of the proposed method are provided. The

13

chapter also provides the result of the questionnaire survey that has been conducted

for validating the developed method.

Chapter 8 discusses the development of guidelines to manage design changes. It

also provides in details the findings from the Delphi study that has been used as a

method to validate the developed guidelines.

Chapter 9 concludes the results of the research. Discussions are made on the

achievement of the objectives of the study, on the contribution of the research to the

existing knowledge and recommendations are made for future research on the

subject.

265

REFERENCES Abd Majid, M. Z. and Mccafer R. (1997). Discussion of Assessment of Work

Performance of Maintenance Contractors in Saudi Arabia. Journal of Management in Engineering, ASCE, 13(5): 91-92.

Abd Majid, M. Z. (1997). Non-Excusable Delays in Construction. PhD. Thesis. Department of Civil and Building Engineering, Loughborough University Loughborough, Leicestershire, UK.

Abou-zeid, A., Russell, J., Hanna, A. and Park, S. (1995). Data Flow Model for Communications between Project Participants in Highway Bridge Project. Canadian Journal of Civil Engineering, Ottawa, Canada, Vol. 22: 1224-1234. Adler, M. and Ziglio, E. (1996). Gazing into the Oracle: The Delphi Method and its Application to Social Policy and Public Health. Jessica Kingsley Publishers, Bristol, London pp358-362 Al-Dubaisi, A. H. (2000). Change Orders in Construction Projects in Saudi Arabia. MSc Thesis, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia. Al-Husaini, M. K. (2005). The Construction Sector: The Actual and Expectation. Oman Chamber of Commerce and Industry, Sultanate of Oman Akinsola, A. O., Potts, K. F., Ndekugri, I. and Harris, F. C. (1997). Identification and Evaluation of Factors Influencing Variations on Building Projects. International Journal of Project Management, 15(4): 263-267. Al-Momani, A. H. (2000). Construction Delay: a Quantitative Analysis. International Journal of project Management, Vol. 18: 51-59.

American Consulting Engineers Council, ACEC, (1982). American Society of Civil Engineers (1985). ASCE, New York, NY, USA. American Society of Civil Engineers, Manual and Reports on Engineering Practice No. 45, (1988). Consulting Engineering: A Guide for the Engagement of Engineering Services. ASCE, New York, NY, USA.

Anderson, S. D. and Tucker, R. L. (1994). Improving Project Management of Design. Journal of Management Engineering, 10(4): pp35-44. Anumba, C. J. (2000). Integrated Systems for Construction: Challenges for the Millennium. Proceedings of the International Conference on Construction Information Technology, Hong Kong, 8-92.

266

Arditi, D., Akan, G. T. and Gurdamar, S. (1985). Reasons for Delays in Public Projects in Turkey. Construct Management Economics, Vol. 3: UK, 171-181. Assaf, S. A., AlKhalil, M. and Al-Hazml, M. (1995). Causes of Delay in large

Building Construction Projects. Journal of Management in Engineering, ASCE, Vol. 11, No. 2, pp45-50.

Association of Consulting Engineers Malaysia, (1998). Explanatory Guide to the Use of BEM Forms and Scale of Fees. Kuala Lumpur, Malaysia. Austin, S. A., Baldwin A. N., Li, B. and Waskett, P. (2000). Analytical Design Planning Technique: A Dependency Structural Matrix Tool to Schedule the Building Design Process. Construction Management Economics, Vol. 18, pp173-182. Austin, S. A., Baldwin A. N. and Steele, J. L. (2002). Improving Building Design

through Integrated Planning and Control. Engineering, Construction and Architectural Management, Vol. l.9, No. 3, pp 249-258.

Baldwin, A. N., Austin, S. A., Hassan, T. M. and Thorp, A. (1999). Modelling Information Flow During Conceptual and Schematic Stages of Building Design. Construction Management Economics, Vol. 17, pp155-167. Baxendale, A. T. and Schofield, T. J. (1996). Planning and Progressing Project

Variations in Langford and Retik. The Organization and Management of Construction: Shaping theory and practice, Vol. 2, E & FN SPON, UK.

Beech, B. (1999). Go the Extra Mile-Use Delphi Technique. Journal of Nursing

Management, Vol. 7, pp 281-288. Biech, E. (1999). Business of Consulting. Jossey-Bass/Pfeiffer, San Francisco,

CA, USA. Blockley, D. I. (1986). Report of the Working Group on Error Control strategies: Modelling Human Error in Structural Design and Construction. National Science Foundation, Washington, D.C. USA. Borcherding, J. D. (1976). Improving Productivity in Industrial Construction. Journal of the construction Division, Proceeding of The American Society of Civil Engineers, 102(C04): USA. Bramble, B. B. and Cipollini, M. D. (1995). Resolution of Disputes to Avoid Construction Claims. Transportation Research Board, National Research Council, Washington D.C. USA. Brockhaus, W. L. and Mickelsen, J. F. (1977). An Analysis of Prior Delphi Applications and some Observations on its Future Applicability. Technical Forcast. Social Change, Vol. 10, pp. 103-110

267

Bromilow, F.J. (1970). The Nature and Extend of Variations to Building Contracts. The Building Economist, Vol. 9, No. 3, pp 93-118.

Bryman, A. (1996). Quantity and Quality in Social Research. Routledge, London, pp201-212 BS, 8110, British Standard, Part 1: (1997). Structural use of Concrete, Code of Practice for Design and Construction. Bubshait, A. A., Al-Said, F. A. and Abolnour, M. M. (1998). Design Fee Versus

Design Deficiency. Journal of Architectural Engineering, ASCE, Vol. 4, No. 2 pp 44- 46.

Burati, J. L., Farrington, J. J. and Led, W. B. (1992). Causes of Quality

Deviation in Design and construction. Journal of Construction Engineering and Management, ASCE, Vol. 118, No.1, pp 34-49.

Burgess, R. G. (1984). In the Field: an Introduction to Field Research. London, Allen and Unwin, UK, pp 23-37 Caballero, A. A., Ahmed, S. M., Azhar, S. and Barcala, M. (2002). Development

of An Information Model to Enhance Integration and Coordination in the Construction Projects. Florida International University, 10555 W. Flagler Street, Miami, Florida 33174, USA.

Cariappa, A. (2000). The Effects of Contract Changes on Performance of

Construction Projects. MSc Thesis, The University of New Brunswick, Canada. Chan, D. W. and Kumaraswamy, M. M. (1994). A Survey of Time-Cost Relationships in Hong Kong Construction Projects. Building Technology and Management Journal, Vol. 20: 54-72. Chan, D. W. and Kumaraswamy, M. M. (1995). Determinants of Construction

Duration. Construction Management and Economics, Vol. 13, No. 3, pp209-217. Chan, D. W. and Kumaraswamy, M. M. (1996). An Evaluation of Construction Time Performance in the Building Industry. Building and Environment, Vol. 31, No. 6, pp569-578.

Chang, A. S. (2002). Reasons for Cost and Schedule Increase for Engineering Design Projects. Journal of Management in Engineering, ASCE, Vol. 18, No. 1, pp 29-36. Charles, T. J. and Andrew, M. A. (1990). Prediction of Cost-Overrun Rates.

Journal of Construction Engineering and Management, ASCE, Vol. 116, No.3, pp 74 -81.

Choy, W. K. and Sidwell, A. C. (1991). Sources of Variations in Australian

Construction Contracts. The Building Economist, pp25-30.

268

Cockman, P., Evans, B. and Reynolds, P. (1992). Client-Centred Consulting. Mcgraw-Hill Book Company Europe, England.

Cohen, S. (1982). Consulting Engineering Practice Manual. Mcgraw-Hill, Inc. New York. USA. Construction Engineering Council, (1993). The Procurement of Professional

Services. Thomas Telford Services LTD, USA. Construction Industry Institute (CII), Publication 6-10, (1990). The Impact of Changes on Construction Cost and Schedule. The University of Texas at Austin, Texas, USA. Construction Industry Institute (CII), Special Publication 43-1, (1994). Project Change Management. The University of Texas at Austin, Texas, USA. Construction Industry Institute (CII), Publication 43-2, (1995). Quantitative Effects of project Change. The University of Texas at Austin, Texas, USA.

Contractors' Directory (1991). Oman Chamber of Commerce and Industry. Sultanate of Oman Corotis, R., Fox, R. and Harris, J. (1981). Delphi Methods: Theory and Design Load Application. Journal of the Structural Division, ASCE, Vol. 107, No. 6, pp 95-105. Cox, R. K. (1997). Managing Change orders and Claims. Journal of Management in Engineering. January/February Issue, ASCE, 24-29. Dalkey, N. C., Rourke, D. L., Lewis, R. and Sayder, D. (1972). Studies in The Quality of Life. Lexington Books, Lexington, Mass, USA Defence Construction Canada, DCC, Administration Manual, (DND, 1992). pp 23-24. Delbeeq, A. L. and Gustafson, D. H. (1975). Group Techniques for Programme

Planning: A Guide to Nominal Group and Delphi Process. Scott Foresman Publishers, Glenview, ILL, USA.

Demkin, J. A. (2002). The Architect’s Handbook of Professional Practice. 13th Edition, John Wiley & Sons, Inc. USA.

Dickey, J. and Watts, T. (1978). Analytic Techniques in Urban and Regional Planning. McGraw-Hill, New York. pp 87-94. Dietz, T. (1987). Methods for Analysing data from Delphi Panels: Some Evidence from a Forecasting Study. Technology Forecasting, Social Change, Vol. 31, pp79-85.

269

Diekmann, J. E. and Nelson, M. P. (1992). Super Change: Expert System for Analysis of Change Claims. Journal of Construction Engineering and

Management, ASCE, Vol. 111, No.1, pp 74-81. Draft, R. L. (1986). Organization Theory and Design. 2nd Edition, West Publishing Co., St. Paul, Minnesota, USA, pp120-131. Dreger, G. T. (1993). Design-Build Procurement: Strategies for Success. Proceeding of CIB W-65 on Organization and Management of Construction: The Way Forward, University of the West Indies, Port of Spain, Trinidad, Spain, pp749-757. Eddy, M. R. and Amlan, M., (2003). Modeling the Construction Management Process to Support Situational Simulations. Journal of Computing in Civil Engineering, ASCE, Vol. 17, No. 4, Pp273-280. Eisenhardt, K. M. (1989). Building Theories from Case Study Research. Academic Management Rev. Vol. 14, No.4, pp532-550. Eldin, N. N. (1991). Management of Engineering/Design Phase. Journal of

Construction Engineering and Management, ASCE, Vol. 117, No.1, pp163-175. Elinwa, A. U. and Buba, S. A. (1993). Construction Cost Factors in Nigeria.

Journal of Construction Engineering and Management, ASCE, Vol. 119, No.4 pp698-713.

Emmitt, S. (2001). Observing the Act of Specification. Design Studies, ASCE Vol. 22, No.5, pp397-408. Essex, R. J. (1996). Means of Avoiding and Resolving Disputes During Construction. Tunnelling and Underground Space Technology, Vol. 11, pp27-31 Federal Construction Council (1983). Consulting Committee on Contract

Management, Technical Report No. 74. Managing Changes in the Construction Process. National Academy Press. Washington D.C. USA.

Fellows, R and Liu, A. (1997). Research Methods for Construction. Blackwell

Science Ltd, UK. Finke, M. R. (1998). A Better Way to estimate and Mitigate Disruption. Journal of

Construction Engineering and Management, ASCE, Vol. 124, No.6, pp490-497. Fisk, E. R. (2000). Construction Project Administration. 6th Edition, Prentice Hall

Upper Saddle River, New Jersy, Columbus, Ohio. USA, pp456-475.

Frimpong, Y., Oluwoye, J. and Crawford, L. (2003). Causes of Delay and Cost Overruns in Construction of Groundwater Projects in a Developing Countries; Ghana as a Case Study. International journal of Project Management, Vol. 21, pp321-326.

270

Ganeshan, R., Garrett, J. and Finger, S. (1994). A Framework for Representing Design Intent. Design Studies, Vol. 15, No.1, pp59-84. Garrat, S. (1991). How to become a Consultant. Gower Publishing Company

Limited, U.K. Gilbreath, R. D. (1992). Managing Construction Contracts. Second Edition, John

Wiley & Sons, Inc., New York, USA, 179-180. Gil, E., Lucchesi, E., Tauber, G. and Onderdonk, D. (1983). Working with

Consultants. American Planning Association., Chicago, IL, USA. Goldfisher, F. (1992). Modified Delphi: A Concept for New Product Forcasting. Journal of Business Forecasting, Vol. 11, No. 4, pp 10-15 Goldstein, N. (1975). In the Delphi Techniques and Applications. Addison Wesley, Reading, MA, USA, pp210-226. Granovetter, M. (1985). Economic Action and Social Structure: The Problem of Embeddedness. American Journal of Sociology, Vol. 9, No. 13, pp481-510. Gunhan, S. and Arditi, D. (2005). International Expansion Decision for

Construction Companies. Journal of Construction Engineering and Management, ASCE, Vol. 131, No. 8, pp928-937. Hanna, A. S., Russell, J. S. and Gotzion, T. W. (1999). Impact of Change Orders onLabour Efficiency for Mechanical Construction. Journal of Construction Engineering and Management, ASCE, Vol. 125, No. 3, pp176-183. Hashimoto, T. (1993). Problem on Design Production for Building Construction: Sharing Roles and Information Among Designers and Builders. Forum for Japanese System, pp49-56. Hartman, F. T. and Baldwin, A. (1995). Using Technology to Improve Delphi Method. Journal of Computing in Civil Engineering, ASCE, Vol. 9, No. 4, pp244-249. Hess, G. R. and King, T. J. (2002). Planning Open Spaces for Wildlife I: Selecting Focal Species using Delphi Survey Approach. Landscape and Urban Planning, Vol. 58, USA, pp25-40 Hester, W. T., Kuprenas, J. A. and Chang, T. C. (1991). Construction Change Orders: Their Magnitude and Impact. Construction Industry Institute, The University of Texas at Austin, Texas, USA. Hegazy, T., Zaneldin, E. and Grierson, D. (2001). Improving Design Coordination for Building Projects. I: Information Model. Journal of Construction Engineering and Management, ASCE, Vol. 127, No. 4, pp322-329.

271

Hew, K. P., Fisher, N., and Awbi, H. B. (2001). Toward an Integrated Set of Design Tools Based on Common Data Format for Building and Services Design. Automation in Construction, Vol. 10, pp459-476 Hibberd, P. R. (1982). Building Contract: Variations. MSc Thesis. The Victoria

University of Manchester, Manchester, UK Hoon, L. P. (1979). Criteria for Selecting of Consultants with Special Reference to

Water Resources Development Study/Project. Seminar on Appointment of Consultants, Kuala Lumpur, Malaysia.

Hurley, M. W. and Touran, A. (2002). Cost Structure and Profitability of Design

Services Industry. Journal of Management in Engineering, ASCE, Vol. 18, No. 4, pp167-172.

Ibbs, C. W. and Allen, W. E. (1995). Quantitative Impacts of Project Change.

Source Document 108, Construction Industry Institute, The University of Texas at Austin, Texas, USA.

Ibbs, C. W. (1997). Quantitative Impact of Project Change: Size Issues. Journal of

Construction Engineering and Management, ASCE, Vol. 123, No. 3, pp308-311. Jehn, K. A., and Shah, P. P. (1997). Interpersonal Relationships and Task Performance: An Examination of Mediating Process in Friendship and Acquaintance Group. Journal of Personality and Social Psychology, Vol. 72, No. 4, pp775-790 Jergeas, G. F. and Hartman, F. T. (1994). Contractors’ Construction-Claims

Avoidance. Journal of Construction Engineering and Management, ASCE, Vol. 120 No. 3, pp553-561

Kartam, S. ( 1999). Generic Methodology for Analyzing Delay Claims. Journal of Construction Engineering and Management, ASCE, Vol. 125, No.6, pp409-419.

Kelvin, Y. (1996). Project Control: Cost/Schedule/Progress Management. Cost

Engineering, Vol. 38, UK Kirby, J. G., Furry, D. A. and Hiks, D. K. (1988). Improvements in Design Review Management. Journal of Construction Engineering and Management, ASCE, Vol. 114, No.1, pp69-82 Kolarevic B. Schmitt, G. Hirschberg, U. Kurmann, D. and Johnson, B. (2000). An Experiment in Design Collaboration. Automation in Construction, Vol. 9. pp 73-81. Kometa, S. T. Olomolaiye, P. O. and Harris, F. C. (1995). An Evaluation of Clients' Needs and Responsibilities in the Construction Process. Engineering, Construction and Architectural Management, Vol. 2, No. 1, pp57-76

272

Krishnamurthy, K. and Law, K. (1995). A Data Management Model for Design Change control. Concurrent Engineering Research and Applications, Vol. 3, No. 4, pp329-343 Kubr, M. (1993). How to Select and Use Consultants. International Labour Office, Geneva. Kumarasivam, K. (1979). Remuneration and Conditions of Contracts. Seminar on Appointment of Consultants, Kuala Lumpur, Malaysia. Kuprenas, J. A. (2003). Project Management Actions to Improve Design Phase Cost Performance. Journal of Management in Engineering, ASCE, Vol. 19, No. 1, pp 25-32 Latham, M. (1994). Constructing the Team. HMSO, London, UK. Leonard, C. A. (1987). The Effect of change orders on Productivity. Revay and Associates, LTD., Montreal, Canada Leonard, C. A. Fazio, P. and Moselhi, O. (1988). Construction Productivity: Major Causes of Impact. AACE Transactions, New York, NY, ppD10.1-D10.7 Ling, Y. Y. Ofori, G. and Low, S. P. (1997). Developing a Model for Selection of Consultants by Design-and-Build Contractors: A Pilot Study. Proceeding of 1st International Conference on Construction Industry Development: Build the Future Together. National University of Singapore, Singapore, pp374-382. Ling, Y. Y. and Tan, Y. W. (2001). Relevance of Network Factor in Selection of

Consultants. Journal of Professional Issues in Engineering Education and Practice”. Vol. 127, No. 4, pp 190-195

Linstone, H. and Turoff, M. (1975). The Delphi Method: Techniques and Applications. Addison Wesley, Reading, MA, pp.3-12 Loo, K. (1979). Remuneration and Conditions of Contracts. Seminar on

Appointment of Consultants, Kuala Lumpur, Malaysia. Love, P. E., Holt, G. D., Shen, L.Y., Li, H. and Irani, Z. (2002). Using System

Dynamics to Better Understand Change and Rework in Construction Project Management Systems. International Journal of project Management, Vol. 20 pp425-436

Lutz, J. D., Hancher, D. H. and East, E. W. (1990). Framework for Design -Quality- Review Data-Base System. Journal of Management in Engineering, ASCE, Vol. 6, No. 3, pp 296-311 Mason, J. (1996). Qualitative Researching. SAGE Publications Ltd, 6 Bonhill Street, London, EC2A 4PU, UK, pp35-47

273

Mayer, R. R. (1980). The Design of social Policy Research. Printice-Hall, Inc., Englewood Cliffs, N.J. 07632, USA, pp8-17 McDermott, P. and Dodd, J. (1984). The Sources, Causes and Effects of Variations on Building Contracts. Final Report of a Study Supported by Science and Engineering Research Council, Construction Study Unit, Brunel University, Uxbridge, UK. Meyers, J. (1994). Changes Resulting from Delays. Construction Change Order Claims, John Wiley and Sons, Inc., Somerset, NJ, USA, pp213-220. Mendenhall, W., Reimuth, J. and Beaver, R. (1993). Statistics for management and Economics. 7th edition, Duxbury Press. Belmont, CA, USA Merrill, W. E. (1982). Air Force Construction Contract Disputes. Report No. LSSR 88-82, U.S Department of Commerce, USA Mitchell, J. C. and Eschenbach, T. G. (1999). Compensation of Consulting Engineers: Legalities and Realities. Journal of Management in Engineering, ASCE, Vol. 15, No. 1, pp 66-73 Mitchell, V. W. (1991). The Delphi Technique: An Exposition and Application. Technical Analysis Strategy Management, Vol. 3, No.4, pp333-358 Mobbs, G. N. (1989). The Influence of Global investment or the decline of the British Commercial imperialism. Public Lecture Series in Estate Management, Collage of Estate Management, Reading, UK Mokhtar, A. H. (1998a). An Information Model for Managing design Changes in a

Collaborative Multi-Disciplinary Design Environment. PhD Thesis, Concordia University, Montreal, Quebec, Canada.

Mokhtar, A., Bedard, C. and Fazio, P. (1998b). Information Model for Managing

Changes in a Collaborative Environment. Journal of Computing in Civil Engineering, ASCE, Vol. 12, No. 2, pp82-92.

Mokhtar, A. H. M. (2002). Coordination and Customizing Design Information

through the Internet. Engineering Construction and Architectural Management, Vol. 9, No. 3 pp222-231

Moony, R. (1995). A call for Quality in Engineering Business. Journal of

Computing in Civil Engineering, ASCE, Vol. 9, No. 3, pp191-193 Morgan, D. L. (1998). The Focus Group Guidebook. Focus Group Kit 1, Sage, Beverly Hills, CA. Moselhi, O., Leonard, C. and Fazio, P. (1991). Impact of Change Orders on

Construction Productivity. Canadian Journal of Civil Engineering, Vol. 18, No.3, pp 481-492.

274

Mosley, W. H., Bungey, J. H. and Hulse, R. (1999). Reinforced Concrete Design. 5th Edition, Palgrave, New York, USA, pp220-241 Newcombe, R., Langford, D. and Fellows, R. (1996). The Sources, Causes and Effects of Variations on Building Construction Study Unit. Brunel University, Uxbridge, UK Nordin, B. (1979). Procedure and Criteria for Selecting and Appointment of

Consultants. Seminar on Appointment of Consultants, Kuala Lumpur, Malaysia. Ogunlana, S. O., Promkuntong, K. and Jearkjirm, V. (1996). Construction Delays in a Fast-Growing Economy: Comparing Thailand with other Economies. International Journal of project Management, Vol. 14, No. 1, pp37-45

Okpala, D. C. and Aniekwu, A. N. (1988). Causes of High Costs of Construction Projects in Nigeria. Journal of Construction Engineering, Vol. 114 No. 2, pp233-244

Oman Chamber of Commerce and Industry (2005). Sultanate of Oman Patton, M. Q. (1987). How to Use Qualitative Methods in Evauation. SAGE Publications Ltd, 6 Bonhill Street, London, EC2A 4PU, UK, pp7-22 Peltonen, H., Mannisto, T., Alho, K. and Sulonen, R. (1993). An Engineering Document Management System. Proceeding of American Society of Mechanical Engineers, Winter Annual Meeting, New York, USA

Pena-Mora, F., Sriram, D. and Logcher, R. (1995). Design Rationale for Computer- Supported Conflict Mitigation. Journal of Computing in Civil Engineering, ASCE, Vol. 9, No. 1, pp57-72

Pocock, J.B., Liu, L. Y. and Kim, M. K. (1997). Impact of Management Approach

on Project Interaction and Performance. Journal of Construction Engineering and Management, ASCE, Vol. 123, No. 4, pp411-418.

Ramanath, A. (1979). Criteria for Selecting of Consultants and Position of Foreign

Consultants. Seminar on Appointment of Consultants, Kuala Lumpur, Malaysia.

Ray, S. S. (1995). Reinforced Concrete Analysis and design. First edition, Black well Science Ltd, Australia, pp215-292 Reynolds, C. E. and Steedman, J. C. (1988). Reinforced Concrete Designer's Handbook. 10th Edition, Rupa Paperback, India, pp 206-216 Rezgui, Y. and Debras, P. (1995). An Integrated Approach for a Model Based Document Production and Management. Electronic Journal of Information Technology in Construction, www/itcom.org Robinson, J. B. L. (1991). Delphi Technology for Economic Impact Assessment. Journal of Transportation Engineering, Vol. 117, No. 3

275

Sinha, S. N. (2002). Reinforced Concrete Design. Second Edition, Tata McGraw -Hill Publishing Company Limited, New Delhi, India, pp301-391 Smith, M. A. (1996). Construction Insurance, Bonding & Risk Management. McGraw-Hill, New York, USA Soh, C. K. and Wang, Z. (2000). Parametric Coordinator for Engineering Design. Journal of Computing in Civil Engineering, ASCE, Vol. 14, No. 4, pp233-240 Southgate, T. (1988). Cost Planning – a New Approach. Chartered Quantity

Surveyors, Journal of the RICS, Vol. 9, No. 10, pp32-38. Spooner, D. and Hardwick, M. (1993). Using Persistent Object Technology to Support Concurrent Engineering System. Concurrent Engineering: Methodology and Applications, P. Gu and A. Kusiak, eds., Elsevier Science, Amsterdam, pp205-234 Ssegawa, J. K., Mfolwe K. M., Makuke, B. and Kutua, B. (2003). Construction

Variations: A Scourge or a Necessity?. Civil Engineering Department, University of Botswana, Gaborone, Botswana, pp81-90.

Stanley, C. M. (1982). The Consulting Engineer. Second Edition, John Wiley &

Sons, Inc. USA Statistical Year Book (August 2002). Ministry of National Economy, Sultanate of Oman Statistical Year Book (August 2003). Ministry of National Economy, Sultanate of Oman Statistical Year Book (October 2004). Ministry of National Economy, Sultanate of Oman Sullivan, A. and Harris, F. C. (1986). Delays on Large Construction Projects. International Journal of Operation Prod. Management, Vol. 6, No. 1, pp25-33 Teicholz, P. and Fisher, M. (1994). Strategy for Computer Integrated Construction

Technology. Journal of Construction Engineering and Management, ASCE, Vol. 120, No. 1, pp117-131

The Institute of Civil Engineers, (1996 ). Civil Engineering Procedure, Fifth Edition, Thomas Telford, UK, pp49-61 The Standard Form of Agreement and Conditions of Engagement for Consultancy Services for Building and Civil Engineering works, Sultanate of Oman (1987) Thomas, H. R. and Napolitan, C. L. (1995). Quantitative Effects of Construction

Changes on Labor Productivity. Journal of Construction Engineering and Management, ASCE, Vol. 121, No. 3, pp290-296

276

Thomas, H. R., Korte, Q. C., Sanvido, V. E. and Parfitt, M. K. (1999). Conceptual Model or Measuring Productivity of Design and Engineering. Journal of Architectural Engineering, ASCE, Vol. 5, No. 1, pp1-7.

Trickey, G. and Hackett, M. (2001). The Presentation and Settlement of Contractor's Claims. Spon Press, London, UK, pp311-320 Turner, D. (1984). Standard Contracts for Building. George Godwin, England Valkenburg, R. C. (1998). Shared Understanding as a Condition for Team Design. Automation in Construction, Vol. 7, pp111-121. Vries, B. and Somers, L. (1995). Message Exchange in the building Industry. Automation in Construction, Vol. 4, pp91-100 Williams, A. P. O. and Sally, W. (1994). Competitive Consultant. The Macmillan

Press LTD. UK. Williams, P. L. and Webb, C. (1994). The Delphi Technique: A Methodological

Discussion. Joutnal of Advanced Nursing, Vol. 19, pp180-186. Wilson, R. L. (1982). prevention and Resolution of Construction Claims. Journal of Construction Division Vol. 108, No.CO3 pp390-405 Yeung, I. Y. and Tung, R. L. (1996). Achieving Business Success in Confucian Society: The Important of Connections. Organizational Dyn., Vol. 25, No., 2, pp 54-65 Yogeswaran, K. (1998). Sources, Causes and Minimisation of Contractual Claims in Civil Engineering Projects in Hong Kong. PhD Thesis, The University of Hong Kong Hong Kong. Zaki, M. K. and James, E. D. (1987). Concurrent Delays in Construction Projects.

Journal of Construction Engineering and Management, ASCE, Vol. 113, No. 4, pp120-126

Zaneldin, E., Hegazy, T. and Grierson, D. (2001). Improving Design Coordination for Building Projects. II: A Collaborative System. Journal of Construction Engineering and Management, ASCE, Vol. 127, No. 4, p330-336.

Zeitoun, A. and Oberlender, G. (1993). Early Warning Signs of Project Changes. Oklahoma State University, CII Source Document No. 91. USA Zhang, X. (2004). Concessionaire Selection: Methods and Criteria. Journal of Construction Engineering and Management, ASCE, Vol. 130, No. 2, pp235-244