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
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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
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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.
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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
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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
7. Mechanical and Electrical Services Elements ... 51
8. Column Spacing ... 52
9. Floor Spans ... 52
10. Constructability ... 53
E. Theory of Construction Costs ... 54
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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
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
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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
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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
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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 2.8. 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
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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
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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
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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.
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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.
