ANALYSING COST IMPLICATIONS OF BUILDING

DESIGN VARIABLES AS AREAS OF MODELLING TO

ACHIEVE VALUE FOR MONEY

A Study on Selected Buildings in Surakarta and

Surrounding Areas

Thesis

Submitted to the Department of Civil Engineering,

Graduate School of Universitas Muhammadiyah

Surakarta

in partial fulfilment of the requirements for

the degree Master of Civil Engineering

By

Ainomugisha Safiki

ID No. S100150005

DEPARTMENT OF CIVIL ENGINEERING

GRADUATE SCHOOL

UNIVERSITAS MUHAMMADIYAH SURAKARTA

2016

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DEDICATIONS

Alhamdulillahi, all praises and thanks are for Allah subhanahu wata-‘aala and

may peace and blessings be upon our beloved prophet Muhammad Swalla Allahu

‘Alayhi wasallam. This thesis is dedicated to the following who have been very

resourceful and supportive during its writing.

1. The lovely mother and dad who have always supplicated for the writer to

succeed.

2. My lovely wife and two children that have always supported and

motivated me to complete this research thesis.

3. My father in law who has always assisted my family during my period of

study outside my motherland.

4. My sponsor for my education of master’s degree i.e. Directorate General

of Higher Education Ministry of Education and Culture Republic

Indonesia (KNB) and Universitas Muhammadiyah Surakarta, department

of Civil Engineering Graduate Studies and all my lectures who have all

contributed to achieving my goal.

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APPRECIATION

Alhamdulillah Rabbul ‘Aalamiin, all praises and thanks go to Almighty Allah

subhanahu wata’ala, who has enabled me to complete this thesis. The author after

Allah’s guidance was able to do this research with supervision and assistance of

many parties. On this the sincerely sends his appreciation and thanks to the

following who have been instrumental in completing this thesis.

1. Dr. Mochamad Solikin, who accepted to be the primary supervisor and his

availability to help, correct the author to complete this thesis.

2. Ir. H.Muh Nur Sahid.MM. MT, who always gave motivation and smooth

running in this thesis until the goal of this thesis was achieved.

3. Head of program of Civil Engineering who has always given all the

necessary assistance and guidance, and always allowed smooth running of

this thesis from inception up to the end.

4. Director VERTECT, Dr. Ir. Dhani Mutiari, MT, who gave in a lot in terms

of assistance to obtain the biggest part of the data that was required for this

thesis from identifying required respondents to other forms of data like

RAB and drawings of study cases used.

Author

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TABLE OF CONTENTS

APPROVAL .................................................................................................... i

PRIMARY SUPERVISOR FORM .................................................................. ii

CO-SUPERVISOR .......................................................................................... iii

STATEMENT OF AUTHORSHIP ................................................................ iv

DEDICATIONS ............................................................................................... v

APPRECIATION ............................................................................................. vi

TABLE OF CONTENTS ................................................................................. vii

LIST OF TABLES ........................................................................................... xi

LIST OF FIGURES ......................................................................................... xii

LIST OF APPENDICES .................................................................................. xiv

ABSTRACT ..................................................................................................... xv

ABSTRAK ....................................................................................................... xvi

CHAPTER I. INTRODUCTION ................................................................ 1

A. Background ..................................................................... 1

B. Problem Identification..................................................... 5

C. Problem Formulation ...................................................... 8

D. Objectives of the Study ................................................... 8

E. Scope and Limitations ..................................................... 9

F. Justification and Benefits of the Study ........................... 10

CHAPTER II. LITERATURE REVIEW .................................................... 12

A The Concept of Building Design ....................................... 12

1. Design relationship that exists between shape/shape, structure

and construction ................................................................... 14

2. Design constraints. ............................................................. 19

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3. A Good Design. ................................................................. 21

B. Theories of Design Variables ............................................ 22

1. Building plan shape. ......................................................... 27

C. Building Economic Theories of Designs ........................... 30

D. Accounting for General Trend for Costs Implications of a

Building ............................................................................. 36

1. Effect on Cost of Substructure ......................................... 37

2. Effect on Cost of Superstructure ..................................... 38

3. Effects on Cost of Block Walling ..................................... 38

4. Effect on Cost of Roof Work............................................ 40

5. Effect on Cost of Services ................................................ 39

6. Effects on Cost Finishes ................................................... 40

E. Other Design Variables ..................................................... 44

1. Size of Building ................................................................. 42

2. Average Storey Height ...................................................... 43

3. Number of Storeys ............................................................. 44

4. Building Envelope ............................................................. 50

5. Circulation Space............................................................... 50

6. Grouping of Building ........................................................ 51

7. Mechanical and Electrical Services Elements ................... 51

8. Column Spacing ................................................................ 52

9. Floor Spans ......................................................................... 52

10. Constructability ................................................................. 53

E. Theory of Construction Costs ................................................. 54

1. Determination of Costs ......................................................... 55

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2. Theories and Practice of Modelling Costs ............................ 56

F. Design Philosophies .............................................................. 59

1. Costing a Design................................................................... 60

2. Designing to Cost ................................................................. 61

G. Value for Money ................................................................... 62

CHAPTER III. RESEARCH METHODOLOGY ...................................... 66

A. Introduction ............................................................................ 66

B. Tools/Equipment and Materials to be Used ........................... 68

C. Research Procedure/Phases .................................................... 68

1. Phase I: Literature Review ................................................... 68

2. Phase II: Survey to Obtain Clients’ and Design Consultants’

Views ................................................................................... 69

a. Required data .................................................................. 69

b. Data Collection ............................................................... 71

c. Population and sample size ............................................. 72

d. Questionnaire design ....................................................... 73

e. Analysis ........................................................................... 73

3. Phase 111: Analysis for Design Variables .......................... 76

CHAPTER IV. RESULTS ANALYSIS AND SISCUSSIONS .................. 81

A. Analysis and Results of Study.............................................. 81

1. Clients’ Priorities on any Building Plan Design .................. 82

2. Building design variables used for modification in VE to

achieve Value for Money ....................................................... 95

3. Consequences of applying design variables as part of VE

practice ................................................................................ 101

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4. General suggestions by respondents on improving design

process so as to achieve value for money ............................ 103

B. Case Study Analysis of Effects of Building Shape on Costs 108

1. Introduction .......................................................................... 104

2. Hypothesis .......................................................................... 105

3. Analysing Effect of Building Shape on Costs ..................... 109

C. Discussion of Study Results ................................................. 117

1. Clients’ Expectations and Priorities for any Building

Design ................................................................................. 118

2. Building Design Variables Used ......................................... 120

3. Value Engineering and Achieving Value for Money ......... 122

4. The Effects of Plan Shape on Costs of Building Construction 123

CHAPTER V. CONCLUSION .................................................................... 128

A. Conclusions .......................................................................... 128

B. Suggestions ........................................................................... 131

C. Implications ......................................................................... 132

D. Recommendations for Further Study ................................... 133

REFERENCES ................................................................................................. 134

APPENDICES ................................................................................................. 141

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LIST OF TABLES

Table 2.1. Correlation factors between designing form of architecture with

designing system of structure ..................................................... 18

Table 2.2. The identified building design variables by previous authors .... 26

Table 2.3. Shows the summary of typical relative proportions of costs of

houses and apartments broken down into four basic elements .. 48

Table 2.4. Cost modeling techniques in widespread use .............................. 59

Table 3.1. List of candidate theories and their hypothesis ............................ 79

Table 4.1. Frequencies’ distribution of questionnaire data for descriptive data

analysis ........................................................................................ 84

Table 4.2. Product moment computation ....................................................... 86

Table 4.3. Descriptive analysis reliability test of data .................................. 87

Table 4.4. Design variables used in modifying designs ................................. 96

Table 4.5. Elemental cost distribution of case study A .................................. 106

Table 4.6. Elemental cost distribution of case study B .................................. 108

Table 4.7. Data describing parameters used of case study buildings ............... 110

Table 4.8. Shows the distribution of the values for selected building indices 111

Table 4.9. Comparison of overall cost per square meter GFA ...................... 113

Table 4.10. Comparison of cost per square meter GFA of elements .............. 113

Table 4.11. Analysis on how the different items of concrete frame varied ..... 115

Table 4.12. Cost saving attained by change in perimeter walling by 1m ........ 116

Table 4.13. Variations experienced on the cost per square meter GFA ........... 117

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LIST OF FIGURES

Figure 2.1. Heinz’s relationship between the client, shape, method and

material of construction ....................................................... 17

Figure 2.2. Relationship between variables; form and system of a structure 17

Figure 2.3. Correlation between design of construction and shape ........ 18

Figure 2.4a & b. Project life cycle and level of influence ......................... 24

Figure 2.5. Shows average cost variations of contract sum for 4 different

plan shapes ............................................................................. 36

Figure 2.6. Elemental cost distribution for case A ................................. 41

Figure 2.7. Variation in element cost per square metre GFA .................. 41

Figure 2.7. Graph of cost relationships on number of storeys ................. 59

Figure 2.8. Simplified relationship between design and cost .................. 55

Figure 3.1. Procedural flow chart diagram............................................... 67

Figure 3.2 Research flow chart ................................................................ 69

Figure 4.1. Field department of work for respondents .............................. 88

Figure 4.2. Average experience of respondents ........................................ 89

Figure 4.3. Educational level of background of respondents .................... 90

Figure 4.4. Development stage at which shape of building is determined 91

Figure 4.5. Parties which greatly determine shape of design ..................... 92

Figure 4.6. Use of VE technique in design development .......................... 93

Figure 4.7. Options taken once budget funds are not enough ................... 94

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Figure 4.8. Variables used for modifying designs .................................... 96

Figure 4.9. Factors affecting choice of shape of a building ...................... 97

Figure 4.10. Factors affecting choice of a building height ........................ 98

Figure 4.11. Factors affecting choice for number of floors to use ............. 99

Figure 4.12. Philosophy of system used in design development ............... 100

Figure 4.13. Positive benefits due to use of design variables under VE .... 101

Figure 4.14. Negative consequences inured due to overdesigning ............ 102

Figure 4.15 Procedure for the analysis of cost implications of building

shape ........................................................................................ 104

Figure 4.16. Elemental cost distribution of case study A ......................... 106

Figure 4.17. Distribution of cost for project B ........................................... 108

Figure 4.18. Variation in cost per square meter GFA ................................ 114

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LIST OF APPENDICES

Appendix A. Research Questionnaire ...................................................... 140

Appendix B. List of Respondents Addresses ............................................ 150

Appendix C. Results Tabulation Table .................................................... 152

Appendix D. Drawings ............................................................................. 156

Appendix E. Revised RAB ...................................................................... 192

Appendix F. Form requesting for data ....................................................... 222

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ABSTRACT

As the deployment of construction economics becomes more desirable today,

studies have shown that the building project can be designed in different forms

and shape with respect to its layout characteristics, each attracting different costs

of construction on same usable floor area. Therefore, this study was aimed at 1)

identifying the main client priorities on any building project and design variables

used; 2) analyzing impact of plan shape design variable of on costs 3) making

recommendations to those involved in building design development, on possible

areas of cost saving and adding value for money. The methodology adopted

involved a questionnaire survey designed based on a 5 pointer likert scale

approach, and distributed among 30 respondents in areas of Surakarta, consisting

of 23 consultants and 7 clients and then study case analysis of two cases i.e. case

A and B, in form of hotels constructed in Jawa Tengah Indonesia. The collected

data was processed using statistical methods of product moment and relative

importance index, previous established building indices, then later descriptive

analysis used in analyzing overall and elemental costs effects of plan shape,

expressed in cost/m2

GFA. The results obtained were, clients highly demand for a

design maintained in its budget cost, its quality and aesthetic, with design

variables of building plane shape, building complexity and building façade as the

mostly used. On the other hand the shape closet to a square was the cheapest, i.e.

1,246,551.3 rp/m2

for case B, 1,518,147.53Rp/m2

GFA for A, a 9.8% difference.

The block walling was most varied in its elemental cost/m2 GFA by 38.7%.

Lastly, author recommends that designers should try as possible to design a form

close to square, since the wider the building shape layout, the more cost effective

it becomes i.e. in terms of reducing on materials especially walling, associated

finishes.

Keywords: building cost, building indices, design variable, wider, plan shape.

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ABSTRAK

Perkembangan ekonomi konstruksi telah menjadi semakin perkara yang dihargai

dalam industri konstruksi, sebagaimana terlihat dari beberapa studi telah

menunjukkan bahwa satu proyek bangunan dapat direncanakan dalam berbagai

bentuk bangunan dari aspek ciri-ciri eksternalnya, dalam waktu yang sama setiap

proyek mempunyai biaya yang bebeda untuk area yang sama. Oleh karena itu,

studi ini dimaksudkan agar 1) Mengidentifikasi faktor-faktor dominan yang

mempengaruhi kebutuhan-kebutuhan owner/pemilik proyek konstruksi gedung

dan desain variabel/parameter yang diterapkan, 2) Menganalisis efek desain

variabel bentuk bangunan terhadap biaya konstruksi sebuah gedung, dan 3) Dapat

merekomendasikan kepada pihak-pihak konstruksi bagaimana dapat meraih Value

for Money dan meminimalisir terjadinya inefisiensi. Metodologi yang diterapkan

ialah survey kuisioner berdasarkan 5 poin skala likert, yang disebarkan antara 30

responden terdiri dari 23 konsultan dan 7 owner, yang kedua, analisis dua studi

kasus A dan B dalam kategori hotel dibangun di Jawa Tengah Indonesia.

Kemudian datanya diolah dengan menggunakan metode statistik yaitu product

moment dan relative importance index, buiding indeks telah ditemukan, diiringi

dengan analisa deskriptif untuk dampak bentuk terhadap biaya elemen dalam

cost/m2

GFA. Hasil penelitian adalah para owner menghargai disain yang

anggaran biayanya tetap, kualitasnya dan estetika terjaga, sementara disain

variabel paling diterapkan adalah bentuk bangunan, building complexity,

membran bangunan (facade). Dari kasus analisa, proyek B yang bentuknya

mendekati persegi adalah yang paling menghemat biaya, yaitu 1,246,551.3 rp/m2

dibandingkan 1,518,147.53rp/m2

GFA for A, selisihnya 9.8%. Elemen pasang

dinding adalah yang dapak terpengaruhi dari bentuk rencana bangunan yaitu

dengan selisih 38.7%. Akhirnya dapat direkomendasikan bagi para perencana

untuk mengusahakan merancang bentuk bangunan yang mendekati persegi sebisa

mungkin, karena hal ini dapat meminimalisir terjadinya inefisiensi dengan

mengurangi pemborosan bahan-bahan konstruksi.

Kata kunci: Biaya bangunan, building indeks, desain variabel, bentuk bangunan