DESIGN PHASE CONSTRUCTABILITY CONCEPTS IN
HIGHWAY PROJECTS
SITI HAFIZAN BINTI HASSAN
A project report submitted in partial fulfilment of the
requirements for the award of the degree of
Master of Science (Construction Management)
Faculty of Civil Engineering
Universiti Teknologi Malaysia
NOVEMBER 2005
ii
ii
iii
To my beloved mother and father, my families, my lecturers, my friends and
my special friend…..Thanks for the everlasting love and supports…..
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ACKNOWLEDGEMENTS
First and foremost, grateful thanks to Allah S.W.T for guiding and helping me in
this dissertation. Giving me chances in a way to complete it.
I would like to extend my deepest appreciation and thanks to my supervisor,
Ir. Dr. Rosli Mohamad Zin for his continuous guidance and encouragement in the effort
to complete this thesis.
I would also like to thank to all the engineers and architects who participated in
the questionnaires survey and field interviews and also to those who were involved
directly or indirectly in the completion of this project.
Last but not least is my appreciation and gratitude to my mum, Puan Wan
Fatimah, my dad, Encik Hassan, my brother, Encik Abdul Aziz, my families, my
friends, Idris, Nik Zilazmi, Fareh, Roslina, Lenny, Aiza and Hasnizar for their
understanding, support and encouragement.
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ABSTRACT
Nowadays, highway construction projects suffer from lack of constructability, which
causes many problems; traffic, substantial number of changes, poor planning, disputes,
cost overruns, poor safety practices and time delays. Some researchers have realized the
seriousness of this shortfall and have suggested solutions to resolve it. Previous studies
indicate that, overall constructability is not being implemented to its full potential in
highway sector. So, this study tries to explore constructability implementation in the
local construction industry particularly the highway sector. The aim of the study is to
establish guideline that can be used by engineers in order to improve constructability of
highway project design. The findings of the study shows there were eighteen design
phase constructability concepts that are ‘very important’ and ‘important’ in highway
sector. For the level of application, it was found that most of the concepts are in
‘medium application’. It can be concluded that the engineers have the constructability
knowledge but lack of understanding of the concepts. Based on the survey exercise, a
guideline has been developed consisting of two parts which are ‘very important’ and
‘important’. It is expected that by having this guideline, engineers will be able to apply
this concepts effectively in highway project design in Malaysia.
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ABSTRAK
Kesan daripada kurangnya aplikasi kebolehbinaan dalam pembinaan jalanraya pada
masa kini telah menyebabkan berlakunya banyak masalah dalam pembinaan seperti
lalulintas, perubahan rekabentuk, perancangan yang lemah, pertikaian, kos projek yang
melebihi nilai projek sebenar, sistem keselamatan yang lemah, serta kelewatan masa
penyiapan projek itu sendiri. Para penyelidik telah mengenalpasti betapa seriusnya
masalah ini dan telah mencadangkan beberapa penyelesaian dalam menyelesaikannya.
Kajian terdahulu menunjukkan bahawa keseluruhan kebolehbinaan ini tidak
dilaksanakan secara sepenuhnya di dalam projek jalanraya. Maka, kajian ini cuba
meninjau perlaksanaan kebolehbinaan ini di dalam projek pembinaan jalanraya
setempat. Matlamat kajian ini adalah untuk menghasilkan satu garis panduan agar boleh
digunakan oleh para jurutera dalam usaha untuk mempertingkatkan lagi penggunaan
kebolehbinaan dalam fasa rekabentuk di dalam projek jalanraya. Hasil daripada kajian
ini menunjukkan bahawa lapan belas konsep kebolehbinaan yang dikaji adalah ‘sangat
penting’ dan ‘penting’ dalam projek jalanraya. Dari segi tahap penggunaan konsep ini
pula, didapati bahawa semua lapan belas konsep yang dikaji di bawah kedudukan
‘penggunaan pertengahan’. Dapat disimpulkan bahawa jurutera di Malaysia mempunyai
pengetahuan mengenai kebolehbinaan ini, tetapi kurangnya pemahaman dari segi
konsep-konsepnya. Berdasarkan pemerhatian kajian yang dijalankan, garis panduan
telah dibentuk di mana ia mengandungi dua bahagian iaitu ‘sangat penting’ dan
‘penting’. Adalah dijangkakan bahawa dengan adanya garis panduan ini, jurutera boleh
mengaplikasikan konsep-konsep ini secara berkesan di dalam rekabentuk projek-projek
jalanraya di Malaysia.
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TABLE OF CONTENT
CHAPTER
TITLE
PAGE
THESIS TITLE
i
DECLARATION SHEET
ii
DEDICATION
iii
ACKNOWLEDGEMENT
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
xi
LIST OF FIGURES
xiv
LIST OF APPENDIX
xvi
1
INTRODUCTION
1
1.1
Introduction
1
1.2
Problem Statement
3
1.3
Aim and Objectives of the Study
4
1.4
Scope of Research
4
1.5
Research Methodology
4
viii
2
LITERATURE REVIEW
6
2.1
Constructability Definitions
6
2.2
General Overview Constructability in
7
Highway Project
2.3
2.2.1 Government Agency Observations
8
2.2.2 Design Firm Observations
11
2.2.3 Construction Firm Observations
14
Constructability in the Highway
14
Construction Project Process
2.3.1 Feasibility Design Stages
16
2.3.2 Design Stages
17
2.3.3 Construction
18
2.3.4 Operation
18
2.4
Maximum Benefit of Constructability
19
2.5
Constructability Concepts in Highway Projects
22
2.6
Design Phase Constructability Concepts
32
2.6.1 Carry Out Thorough Investigation of the Site 34
2.6.2 Design for Minimum Time Below Ground
36
2.6.3 Design for Simple Assembly
39
2.6.4 Encourage Standardisation/Repetition
40
2.6.5 Design for Preassembly or Modularisation
40
2.6.6 Analyse Accessibility of the Jobsite
41
2.6.7 Employ Any Visualisation Tools
42
to Avoid Physical Interference
2.6.8 Investigate Any Unsuspected Unrealistic
42
or Incompatible Tolerances
2.6.9 Investigate the Practical Sequence of
43
Construction
2.6.10 Plan to Avoid Damage to Work by
Subsequent Operations
43
ix
2.6.11 Consider Storage Requirement at
43
the Jobsite
2.6.12 Investigate the Impacts of Design on
44
Safety during Construction
2.6.13 Design to Avoid Return Visit by Trade
45
2.6.14 Design for the Skills and Resources
45
Available
2.6.15 Consider Suitability of Designed Materials 46
2.6.16 Provide Detail and Clear Information
45
2.6.17 Design for Early Enclosure
46
2.6.18 Consider Weather Effect in Selecting
Materials or Construction Methods
2.7
3
48
RESEARCH METHODOLOGY
3.1
Introduction
50
3.2
Research Process
50
3.3
Determining the Research Objectives
51
3.4
Steps in Methodology
52
3.4.1 Conceptualization
52
3.4.2 Literature Review
53
3.4.3 Questionnaire
53
3.4.4 Analysis
56
Development of Guidelines
57
3.5
4
Summary
47
DATA ANALYSIS AND DISCUSSION
4.1
Introduction
58
4.2
Respondent’s Background
59
4.2.1 Type of Organization
59
4.2.2 Level of Education
60
x
4.3
4.4
4.5
4.2.3 Field of Specialization
61
4.2.4 Position in Organization
62
4.2.5 Numbers of Years Practiced in Designing
63
4.2.6 Numbers of Years Practiced in Working
64
Level of Importance
66
4.3.1 Frequency Analysis
66
4.3.2 Average Index Analysis
77
Level of Application
81
4.3.3 Frequency Analysis
81
4.3.4 Average Index Analysis
91
The Development of Design Phase
95
Constructability Improvement Concepts
4.6
5
Discussion
99
CONCLUSION AND RECOMMENDATIONS
5.1
5.2
Conclusion
100
5.1.1 Objective 1
100
5.1.2 Objective 2
104
5.1.3 Objective 3
105
Recommendations
105
REFERENCES
107
APPENDIX
110
xi
LIST OF TABLES
TABLE NO.
TITLE
PAGE
4.1
Type of Organization
59
4.2
Level of Education
61
4.3
Field Of Specialization
62
4.4
Position in Organization
63
4.5
Number of Years Practiced in Designing in
64
Highway Projects
4.6
Number of Years Practiced in Working in
65
Highway Projects
4.7
Carry out Thorough Investigation of the Site
66
4.8
Provide Detail and Clear Design Information
67
4.9
Analyze Accessibility of the Jobsite
67
4.10
Investigate the Impacts of Design on Safety
68
during Construction
4.11
Consider Suitability of Designed Materials
69
4.12
Investigate the Practical Sequence of Construction
69
4.13
Consider Adverse Weather Effect in Selecting Materials
70
or Construction Methods
4.14
Plan to Avoid Damage to Work by Subsequent
71
Operations
4.15
Investigate Any Unsuspected Unrealistic or
71
xii
Incompatible Tolerances
4.16
Designs for the Skills and Resources Available
72
4.17
Consider Storage Requirement at the Jobsite
72
4.18
Design for Minimum Time below Ground
73
4.19
Design for Early Enclosure
73
4.20
Encourage Standardization/Repetition
74
4.21
Employ Any Visualization Tools to Avoid
74
Physical Interference
4.22
Design for Simply Assembly
75
4.23
Design to Avoid Return Visit by Trade
76
4.24
Design for Preassembly and/or Modularization
76
4.25
Average Index Value for Degree of Importance of
79
Constructability Concepts during the Design Phase
4.26
Carry Out Thorough Investigation of the Site
81
4.27
Employ Any Visualization Tools to Avoid
82
Physical Interference
4.28
Encourage Standardization/Repetition
82
4.29
Consider Storage Requirement at the Jobsite
83
4.30
Design for Minimum Time below Ground
83
4.31
Investigate the Practical Sequence of Construction
84
4.32
Design for Simply Assembly
84
4.33
Design for the Skills and Resources Available
85
4.34
Investigate the Impacts of Design on Safety during
86
Construction
4.35
Analyze Accessibility of the Jobsite
86
4.36
Design For Preassembly and/or Modularization
87
4.37
Investigate Any Unsuspected Unrealistic or
87
Incompatible Tolerances
4.38
Design to Avoid Return Visit by Trade
88
4.39
Design for Early Enclosure
88
4.40
Provide Detail and Clear Design Information
89
xiii
4.41
Plan to Avoid Damage to Work by Subsequent
89
Operations
4.42
Consider Suitability of Designed Materials
90
4.43
Consider Adverse Weather Effect in Selecting Materials
90
or Construction Methods
4.44
Average Index Value for Degree of Application of
Constructability Concepts during the Design Phase
93
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LIST OF FIGURES
FIGURE NO.
TITLE
PAGE
1.1
Research Methodology Chart
5
2.1
The Highway Construction Project Process
16
2.2
Project Life Cycle and Designers Level of Influence
20
2.3
Ability to Influence Final Cost Over Project Life
21
2.4
Process of launching girder for elevated structure
35
2.5
Problems faced during launching of some girders
35
2.6
Details of elevated highway
37
2.7
Problem of compaction and result after
38
project start-up
3.1
Steps in Methodology
52
3.2
Questionnaire Flow Chart
55
4.1
Percentage of type of organization
60
4.2
Percentage of level of education
61
4.3
Percentage of field of specialization
62
4.4
Percentage of Position in Organization
63
4.5
Percentage of Number of Years Practiced in
64
Designing In Highway Projects
4.6
Number of Years Practiced in Working in
65
Highway Projects
4.7
Degree of Importance of Constructability Concepts
80
xv
4.8
Degree of Application of Constructability Concepts
94
4.9
Design Phase Constructability Improvement Concepts
96
For Malaysian Highway Projects
xvi
LIST OF APPENDIX
APPENDIX
A
TITLE
Questionnaire Form
PAGE
110
CHAPTER 1
INTRODUCTION
1.1
Introduction
Government and private agencies that carried out highway construction
project are facing the reality that the public will no longer tolerate construction
projects that are insensitive to road users and adjacent communities. According to
Russell et al. (1993), highway construction projects are characterized by traffic
problems, changes of design, poor planning, disputes, cost overruns, poor safety
practices and time delays. Constructability is seen as one of the best solutions to
these problems where it has demonstrated the potential to minimize the number and
magnitude of changes, disputes, cost overruns, and delays during construction.
Constructability has been defined in a number of ways. Constructability is
described as the optimum use of construction knowledge and experience in planning,
design, procurement, and field operations to achieve overall project objectives
(Constructability, 1986). Constructability is also defined as a measure of the ease or
expediency with which a facility can be constructed (Hugo et al., 1990). Lastly,
constructability is often portrayed as integrating construction knowledge, resources,
2
technology and experience into the engineering and design of a project (Anderson et
al., 1995).
Highway project constructability can be particularly demanding for a range of
reasons. For example, some of the highway construction technologies are varying
hastily, and, as with most construction, the personnel is transient and site conditions
can vary to the highest degree. Nearly all projects are subjected to severe public
scrutiny involving open competitive bidding, thereby separating the planning and
execution phases and largely precluding a fast-tracked approach to construction.
Designs standards, authored by a multitude of organizations abound and often limit,
if not discourage selective innovation. The prerequisite for nonproprietary
specifications often leads to vagueness. In general, the perception is that project
durations are longer than necessary and that construction costs can possibly be
lowered. As a result, specifications supportive of constructability become an
important element for improving project performance (Hugo et al., 1990).
Beside the project performance, constructability also has been successfully
used to reduce project durations. Eldin (1996) provides several examples of projects
that have successfully used constructability to reduce project durations without
increasing project cost. In a CII (1995) study five projects were analyzed, reporting
11 to 30% reductions in project duration directly attributed to constructability
reviews (i.e., without cost increases). Although the majority of the projects were
associated with industrial facilities, one of them was an interstate highway
realignment that included the reconfiguration of eight bridges and the construction of
two new bridges to facilitate the addition of a high occupancy vehicle lane in each
direction (Eldin, 1996).
Constructability review is the phase of construction project management
where an independent and detailed analysis of all the contract drawings and
construction documents is conducted before their release for construction. An
effective constructability review process has the potential to incorporate into design
3
documents the best practices, guidelines, checklist, and lessons learned from
previous projects, thereby improving the ease of construction and reducing life cycle
costs. This critical process evaluates the “ability to construct” your construction
project (Milstead, 1997). Constructability reviews of highway projects during design
have the potential to minimize the number and magnitude of changes and delays
during construction and thereby reduce durations (Anderson and Fisher 1997). A
constructability analysis of six highway projects suggests that benefits may be as
large as 25 times greater as costs (Anderson and Fisher 1997). Improved processes
and management for effectively using constructability reviews to reduce total project
durations can potentially improve construction project management. The way how
to provide the best constructability review is by improving the understanding of
application and importance of constructability concepts in highway projects.
1.2
Problem Statement
Nowadays, highway construction suffers from lack of constructability, which
causes traffic problems, changes of design, poor planning, disputes, cost overruns,
poor safety practices and time delays. Researchers in developed countries have
realized the seriousness of this shortfall and suggested solutions to resolve it. In
Malaysia, research in constructability in highway projects has not been popular
researched yet. One of the reasons is due to lack of understanding of constructability
concepts among the engineers. Design Phase Constructability Improvement
Concepts for Malaysian Highway Projects should be developed, that are aimed at
encouraging the project team to apply them, where appropriate, to their projects. The
basic message is that applying these constructability concepts will enhance project’s
constructability, consequently optimizing the schedule, cost and quality of the project
for the benefit of all parties involved.
4
1.3
Aim and Objectives of The Study
The aim of this study is to establish Design Phase Constructability Guidelines
For Highway Projects in Malaysian Construction Industry. In order to achieve it,
the following objectives have been identified:
a) To identify the constructability concepts in highway projects.
b) To identify the level of importance and application of constructability concepts in
highway projects.
c) To establish Design Phase Constructability Improvement Guidelines for highway
projects.
1.4
Scope of Research
This research was carried out by questionnaires and interviews. The research
focused on Malaysian Highway Projects with contract values of more than RM 5
million. The questionnaires were distributed to the senior construction management
team like engineers, architect or project manager and etc, who involved in highway
projects.
1.5
Research Methodology
The methodology of research were help to realize the essential stages of
methodology performed or steps of process carried in order to achieve the objectives
5
of this research. Figure 1.1 shows the research methodology chart that has been used
in this research.
CONCEPTUALIZATION
•
Phase 1
Design phase constructability
concepts in highway projects
LITERATURE REVIEW
QUESTIONNAIRE
SURVEYS
•
•
DATA ANALYSIS
Phase 2
Level of importance and
application of constructability
concepts
Design Phase Constructability
Improvement Guidelines for
highway projects.
CONCLUSION/
RECOMMENDATION
Figure 1.1 Research Methodology Chart
CHAPTER 2
LITERATURE REVIEW
2.1
Constructability Definitions
The Construction Industry Institute “CII”, a national construction-research
consortium, gives the following definition (“Constructability” 1986), quoted by the
ASCE Committee on Construction and Management (1987), O’Connor et al. (1988)
and O’Connor et al. (1993): “Constructability is the optimum use of construction
knowledge and experience in the planning, engineering, procurement and field
operations to achieve overall project objectives.”
Eldin (1988) states that “Constructability is the integration of construction
knowledge into all project phases as an effective means for reducing the project costs
and the time required for its completion.” Further, constructability may be described
as “the ability of project conditions to enable the optimal utilization of construction
resources” (O’Connor et al., 1986). Constructability is the integration of
construction expertise into the planning and design of a project so that the
construction forces have the maximum opportunity to deliver the project in
conformity with cost, quality, and schedule and safety objectives of the project’s
stakeholders. Others posit that constructability is simply a matter of using features of
7
the site itself to make the work easier and faster (Kerridge, 1993). In the United
Kingdom, the term buildability is defined as follows (“Buildability” 1983:
“Buildability is the extent to which the design of the building facilitates ease of
construction, subject to the overall requirements for the completed building.”
Similarly, Ferguson (1989) defines buildability as “The ability to construct a
building efficiently, economically and to agreed quality levels from its constituent
materials, components and sub-assemblies.”
These definitions stress the importance of overall project objectives, but the
one that directly addresses the design-construction interface is more efficient in this
study. So the definition from Fisher (1997) that “Constructability is the extent to
which the design facilitates ease of construction, subjected to the requirements of
construction methods” has been adopted in this study.
2.2
General Overview of Constructability in Highway Project
Constructability in the highway industry has gained consideration attention
over the past decades. Early research by O’Connor et al. (1991) identified that poor
specifications can cause construction rework and delays. In fact, these authors state
that 22% of all constructability problems are related to ineffective communication of
engineering information, plans, and specifications, especially inadequacies in project
specifications. This latter problem was confirmed in a national level study by
Anderson et al. (1999).
Based on a survey of government transportation agencies, Anderson and
Fisher (1997) identified two of the three most critical issues related to implementing
8
constructability in transportation projects as the lack of response to designers and
inadequate time to review. These issues are largely addressed by project managers
through their decisions concerning the resources allocated to constructability reviews
and the time spent on constructability reviews. The result of this work suggests that
a lack understanding of the management of constructability reviews is an important
barrier to reducing project durations. The current work tests the impacts of the two
parameters identified by Anderson and Fisher (1997).
Before the government transportation agencies management can address
constructability implementation, critical issues affecting implementation must be
understood. A survey by Stuart et al. (1999) was conducted to capture specific
constructability issues from the perspective of agencies, design firms and
construction contractors. The following were the result from the survey.
2.2.1
Government Agency Observations
There were seven factors involved, which are Lack of Response to Designers,
Enhancement of Plans and Specifications, Inadequate Time to Review, Lack of
Practical Construction Experience by Design Personnel, Traffic Control, Cost and
Manpower.
2.2.1.1 Lack of Response to Designers
The contracting condition in which government agencies operate makes it a
challenge for designers to obtain construction feedback for future project planning
9
and design. By the time that the contractor enters the project, the design is usually
100% complete. This clear separation between the design and construction phases
makes it difficult to apply constructability.
2.2.1.2 Enhancement of Plans and Specifications
Poor plans and specifications can cause major delays, claims and rework.
Many agencies consider the need to improve plans and specifications a major issue in
achieving a constructible project. The effective communication of engineering
information is important in achieving efficient construction, resulting in time and
cost savings. In the transportation industry, the effectiveness of the plans and
specifications takes even greater importance because of the separation of the design
and construction phases. Enhancement of plans and specifications remain the best
approach to conveying the design intent to contractors. Constructability reviews
would help communicate the design intent, thus enhancing a project’s
constructability.
2.2.1.3 Inadequate Time to Review
Their main concern seems to be the lack of time to apply a detailed analysis
of designs from a construction perspective. Maintaining the status quo is considered
the quickest way to meet the design schedule. Changing the process may be
considered a potential source of delay in design operations. Increasing pressures to
meet schedule have actually influenced their formalization of constructability
reviews in an attempt to make them more efficient.
10
2.2.1.4 Lack of Practical Construction Experience by Design Personnel
The separation of design and construction phases in the design-bid-build
contracting environment makes it difficult for designers to expand construction
experience. Once the design is complete, most designers leave the project. The lack
of any formal requirement to maintain a lessons-learned database will hinder
constructability even further. Experienced designers have few mechanisms for
passing their knowledge to newly hired personnel.
2.2.1.5 Traffic Control
The successful of a highway project often depends on an adequate level of
traffic control planning. Poor traffic control management can effect in major delays,
safety hazards and costs. Construction input can be valuable to the development of
an effective traffic control plan. Lessons learned databases could also help in this
area. Studies should be performed on site characteristics and traffic patterns that will
result in maximum savings in time and overall cost of the project. This analysis
should begin early during the planning phase and include construction input.
2.2.1.6 Cost
The cost of implementing a formal constructability process is a concern for
many agencies. The money up front has always been a deterrent to implementation
of constructability in the construction industry (Constructability 1993). It is crucial
that agencies understand that benefits returned will more than offset costs to
11
implement and apply a formal constructability program. Benefit/ cost data confirms
this and reflects a $25 project cost savings for every dollar spent on constructability
reviews (Anderson and Fisher, 1997).
2.2.1.7 Manpower
Turning over personnel absolutely for the purpose of constructability could
result in increased cost to the agency. This is a difficult issue, especially with many
agencies downsizing their operations. Hence, the process has to be flexible enough
so that implementation can fit into the actual structure of the agency without adding
substantial new manpower requirements.
2.2.2
Design Firm Observations
From the design firm observations, the issues are Inadequate Coordination of
Designs, Plans and Specifications, Need of Experience and Knowledge, Poor
Communication and Feedback, Inadequate Time and Funds for Constructability,
Early Review of Designs, Uncoordinated Timing and Phasing, and Scheduling.
12
2.2.2.1 Inadequate Coordination of Designs, Plans, and Specifications
This issue addresses the particular problem of a lack of coordination between
designers and constructors, which results in poor coordination and interaction with
construction. It has been described by respondents in terms of not enough design
detail for construction, inefficient and inflexible designs, designs not coordinated
with utilities within the scope of the project, and a lack of clarity in design criteria
that must be met by the project. This issue becomes even more critical in its relation
to other significant issues that impede constructability poor communication and
feedback inadequate application of construction experience and lack of contractor
input to the design process.
2.2.2.2 Need of Experience and Knowledge
It was evident from responses within the design community that a major issue
with respect to facilitating the constructability process is the need of construction
experience and knowledge among designers. This issue is resolved within most
firms by assigning design review responsibilities to senior design personnel.
However, it is apparent that this effort does not effectively bridge the gap between
designers and constructors so that efficient constructability analysis results.
2.2.2.3 Poor Communication and Feedback
Unfortunately, this issue is one that is common to the inefficient internal
operations of many organizations and is especially critical with respect to
13
constructability. Communications about project designs, plans, and specifications
must be clearly understood by everyone involved in, as well as across the interfaces
of, the planning- preparation-review processes. The contractor who is expected to
apply designs must similarly understand communications. Feedback is essential to
the ‘‘learning process’’ but, unless encouraged and acted upon, offers little to support
the final outcome of a project.
2.2.2.4 Inadequate Time and Funds for Constructability
This response is indicative of what seems to be the traditional method of
performing work with regard to the planning-design-construction process.
Constructability has not been embraced by many organizations to date, and time and
funding simply have not been allocated for such an effort. As with programs such as
value engineering, partnering, and total quality management, constructability must
have the support of an organization’s leadership and management personnel so that
time and funds may be allocated and benefits realized from these programs.
2.2.2.5 Early Review of Designs
The early review of designs was deemed necessary as essential to the
completion of correct and detailed designs as well as designs that would be
effectively implemented by construction contractors. Because this issue has been
raised, many design organizations must believe that early review is an area in which
there is a shortfall of effort. There should be more emphasis on review of plans and
designs early in the overall project process. This is consistent with the concept of
constructability.
14
2.2.2.6 Uncoordinated Timing, Phasing, and Scheduling
It is significant that this issue is critical to effective project management
across the design/construction interface and is related to some of those issues
indicated above, such as poor communication and feedback. It is fundamental that
such issues be managed and overcome so that constructability can be realized
throughout the overall project process.
2.2.3
Construction Firm Observations
The five most critical construction firm issues are listed below. Each of these
has already been discussed as a design firm issue. Their potential impact on
constructability for construction firms is similar to that described for design firms:
• Vague designs, plans, and specifications
• Poor scheduling and phasing of construction
• Need of communications and feedback
• Need of experience and knowledge
2.3
Constructability in Highway Construction Project Process
Construction of a project may be performed by several delivery methods. For
the purpose of this research a traditional method was assumed because it is by far the
most generic construction process Gould (1997) and it is this model that is usually
applicable to infrastructure projects such as found in the great majority of road
15
construction projects. The diagram in Figure 2.1 is presented as the traditional
construction process that consists of the feasibility or preliminary design, design,
construction and operation phases. Although constructability is applied in all project
phases this research project focuses on constructability in the design phase.
In its possible terms of reference constructability remits aims to improve the
integration within the total construction process of those parties that combine to
procure, brief, design, construct, use and maintain a building or engineering product.
Moreover, as a concept it seeks to interrelate the various separate phases of
construction to produce a set of concepts that are implied and accepted and,
inherently, apply constructability thinking to each stage for the benefit of the whole
process. Essentially, constructability is usually seen as the contribution that design
can make to assist construction work on site, but though this is vitally important, and
a major part it is only one element in understanding the full concept (Griffith and
Sidwell, 1988)
To appreciate more fully the contribution that constructability can make, it is
important to outline briefly what construction process seeks to achieve. Since the
mid-nineteenth century, the design element of the construction process has
increasingly diverged from the construction functions on site (Griffith and Sidwell,
1988). This situation produced a process in which the designer and contractor are
both unsure as to the other’s role and function. This can only lead to designs that fail
to bring out the best facets of design. The needs of clients, who want the best from
their project, demand that constructability must be considered at each stage in the
construction process.
16
Feasibility/
Preliminary Design
Design
Construction
Operation
Figure 2.1: The Highway Construction Project Process (Adapted from Garry D.
Creedy, 2003)
2.3.1
Feasibility or Preliminary Design Stages
Normally a project begins with a concept, where conceptual planning or a
preliminary design will be performed and feasibility assessment will be made.
During this feasibility phase conceptual drawings or a preliminary design is produced
to help establish the feasibility of a project. The owner is also establishing
requirements during this phase and therefore the concept’s scope may fluctuate.
17
Traditionally, constructability is not thought of at all at the feasibility phase,
yet subsequently it will seen that modern construction demands that constructability
be considered at this early stages. For example, within the client’s outline idea of
need and requirement constructability can provide feedback from past projects to aid
consideration of the current project. Constructability is also concerned with the basic
method of procurement and employment of consultants. For example, consideration
of constructability can involve evaluating the arrangement of the parties by
suggesting the advantages and disadvantages of the traditional route as against
design-build, management-based systems or design-and-manages approaches.
Constructability can assess not only the technological aspects and potential methods
of construction, but also the formal arrangement between the participants.
2.3.2
Design Stages
If the project is feasible in terms of a sound business case, then a detailed
design is performed. The design phase of a project will produce detailed drawings,
specifications and quantity and cost schedules. During the design phase cost control
is performed through scope control and value engineering. Value engineering is a
team effort between designers, owners and builders to optimize the cost of a project.
It is best applied in the design phase of a project and can result in savings of between
5-10% of construction costs.
The consideration of constructability is basic to this phase, as it allows the
detailed scrutiny of alternative design solutions and of the ergonomics of layout, both
internally and externally, it also helps to determine how the design solution can
directly increase ease of construction on site when the work is carried out. The broad
design situation is critical to constructability for example, uncomplicated
construction using repetitive elements may have a high constructability factor,
whereas a bespoke construction project may be intrinsically costly and have a lower
18
factor of constructability because it incorporates innovative materials or requires
specialized assembly.
2.3.3
Construction
During the construction phase the actual physical building of the project is
accomplished. This stage is comprised of two parts, planning and execution. During
the planning phase a detailed time schedule is developed and in the execution phase
the actual project gets built. Contractor is the person who responsible for the
constructability during the construction phase. He must consider all aspect of
constructability in undertaking all aspects of the site production process. This means
that he also assumes that responsibility for ensuring that general concepts of
constructability are also carried out by the subcontractors and other providers of
specialist inputs to the process. Good relationship with the design team also
important in order to provide feedback on the construction phase for future analysis
and the betterment of knowledge. The key to effective and efficient constructability
on site is good planning, adequate resources and continuous control, which add up to
good general site practice.
2.3.4
Operation
The operation of a new facility begins once the construction is completed. As
soon as the contractor’s final payment and release of retention has been made,
another and final phase of the project begins. At this point, assuming that all
contractual obligations of both parties have been met, the project manager takes over
all of the activities regarding the project, and the project operation activities start.
19
From the explanation above, it can be conclude that constructability is
considered in every stage in project process. In achieving high application and
maximum benefit of constructability, construction personnel play the important roles
in using construction method and construction knowledge about constructability
itself.
2.4
Maximum Benefit of Constructability in Highway Projects
Constructability can be implemented throughout the entire project process i.e.
from the preliminary stage to the operation stage. Since the development of a project
evolves through different stages and involved many participants over its lifecycle
thus the contributions of constructability improvements by each of the participants
vary accordingly. Among many of participants involved in the project, the designers
are expected to play the central role for constructability improvement (Hassan,
1997). Designers are seen to have significant roles as they are responsible for most
technical problems which arise during project design, in the construction and
commissioning of the project.
Figure 2.2 illustrates the stages of project life cycle and the designer level of
influence on the project cost over the project time. It can be seen that the level of
influence of the designer is higher at the beginning of the project and decreasing
towards the end of project. On the other hand the expenditure is increasing as the
project progresses. The figure also illustrates that the best time to achieve good
constructability of project design is at the earlier stages of project development.
20
CONCEPTUAL PLANNING
DESIGN
PROCUREMENT
CONSTRUCTION
COMMISSIONING
MAINTENANCE
START
COMPLETE
High Influence
Low
Low
Expenditure
Expenditure
Low Expenditure
Low Influence
Results Results
High Expenditure
100%
Increasing
Expenditure
Cumulative Project Cost
Level Of Influence
Decreasing
Influence
0%
Project Time
Figure 2.2: Project Life Cycle and Designers Level of Influence (Adapted from
Hassan, 1997)
There have been reports that indicate many problems that are encountered
during construction can be traced back to the design process (Jergeas, 1989; Alshawi
and Underwood, 1994; Madelsohn, 1997; Griffith and Sidwell, 1995). These
problems can be as high as 75% of the total problems encountered during
construction (Madelsohn, 1997).
In view of the problem it is necessary that constructability of project designs
be improved in order to minimise the design-related problems during construction.
21
The need is more critical especially in the context of the Malaysian construction
industry where constructability has been neglected for quite sometimes. The
constructability improvement will eventually improve the efficiency of the
construction industry. This early constructability improvement is desired, as the
benefits of constructability that can be gained is high and the ‘early cost influence’
can be taken advantage off. The ‘early cost influence’ is a concept where the ability
to influence the project cost decreases with the project lifetime. Figure 2.3 depicted
the cost influence of constructability implementation throughout the project lifecycle.
Figure 2.3: Ability to Influence Final Cost Over Project Life (CII (1986)
‘Constructability – A Primer’
22
2.5
Constructability Concepts in Highway Projects
Concept is a significant, distinct and executable objective for enhancing
constructability. Concepts are not specific or unique with respect to project type or
organization. It presents a desperate need and requirement to improve the
construction project constructability (O’Connor et al., 1987).
Several basic researches on constructability have been developed over the last
two decades. The Construction Industries Research and Information Association
(CIRIA) initiated one of the early studies in the development of constructability
concepts in the UK. CIRIA identified seven concepts of constructability concepts for
implementation during design phase and called them “Buildability Concepts”
(“Buildability: An Assessment” 1983). The study was quoted by Powell (1983) and
these concepts are:
1. The thoroughness of design and investigation.
2. Planning for site production requirements.
3. Planning for practical sequence of operations and early enclosure.
4. Planning for simplicity of assembly and logical trade sequences.
5. Detailing for maximum repetition and standardization.
6. Detailing for achieving tolerances; and
7. Specify robust and suitable materials.
Another basic study in this field is the study of O’Connor et al. (1987)
published in June 1987 which presented seven concepts for improving
constructability during the above two phases. These concepts have been adopted by
CII in August 1987 and listed below:
23
1. Constructability is enhanced when design and procurement schedules are
construction-driven.
2. Constructability is enhanced when designs are configured to enable efficient
construction.
3. Constructability is enhanced when design elements are standardized and
repetition is taken advantage of.
4. Constructability is enhanced when pre-assembly work scoped in advance and
module pre-assembly designs are prepared to facilitate fabrication, transport,
and installation.
5. Constructability is enhanced when designs promote accessibility of
manpower, materials and equipment.
6. Constructability is enhanced when design facilitate construction under
adverse weather conditions when they exist; and
7. Constructability is enhanced when owner, designer, and constructor
personnel review specifications in detail. It also serves to simplify the field
construction process.
Other basic study are the two written by Boyce (1991) in which he offered
ten concepts for improving constructability during the design phase only and he
called them “The Ten Commandments of KISS Design”. These concepts are:
1. Keep it straight and simple;
2. Keep its specification simple;
3. Keep it shop standard;
4. Keep its standards simple;
5. Keep it standard size;
6. Keep it same size;
7. Keep it square and squatty;
8. Keep it support simple;
9. Keep it site suitable; and
10. Keep its schedule sacred.
24
From Nima (2001), there are twenty three concepts that are discussed in order
to derive the constructability concepts that will be identified according to the
construction project process.
Project constructability enhancement during conceptual planning phase
comprises concepts C1 to C7.
1. Concept C1: The project constructability program should be discussed and
documented within the project execution plan, through the participation of all
project team members.
2. Concept C2: A project team that includes representatives of the owner,
engineer and contractor should be formulated and maintained to take the
constructability issue into consideration from the outset of the project and
through all its phases.
3. Concept C3: Individuals with current construction knowledge and
experience should achieve the early project planning so that interface
between design and construction can be avoided.
4. Concept C4: The construction methods should be taken into consideration
when choosing the type and the number of contracts required for executing
the project.
5. Concept C5: The master project schedule and the construction completion
date should be construction-sensitive and should be assigned as early as
possible.
6. Concept C6: In order to accomplish the field operations easily and
efficiently, major construction methods should be discussed and analyzed indepth as early as possible to direct the design according to these methods.
25
7. Concept C7: Site layout should be studied carefully to perform the
construction, operation and maintenance efficiently, and to avoid the
interfaces between the operations performed during these phases.
Project constructability enhancement during design and procurement phases
comprises concepts C8 to C15.
1. Concept C8: Design and procurement schedule should be dictated by
construction sequence. Thus, the construction schedule must be discussed
and developed prior to the design development and procurement schedule.
2. Concept C9: Advanced information technologies are important to any field
including the field of construction industry. Therefore, the usage of those
technologies will overcome the problem of fragmentation into specialized
roles in this field, hence enhancing constructability.
3. Concept C10: Designs, through design simplification by designers and
design review by qualified construction personnel, must be configured to
enable efficient construction.
4. Concept C11: Projects elements should be standardized to an extent that will
never affect the project cost negatively.
5. Concept C12: The project technical specifications should simplify and
configured to achieve efficient construction without sacrificing the level or
the efficiency of the project performance.
6. Concept C13: The capability of modularization and preassemblies for project
elements should be taken into consideration and studied carefully.
Modularization and preassembly design should be prepared to facilitate
fabrication, transportation and installation.
26
7. Concept C14: Project design should take into consideration the accessibility
of construction personnel, materials and equipment to the required position
inside the site.
8. Concept C15: Design should facilitate construction during adverse weather
conditions. Good effort should be given to planning the construction of the
project under suitable weather conditions. Otherwise, the designer must
increase the project elements that could be pre-fabricated in workshops.
Project constructability enhancement during field operations phase comprises
concepts C16 to C23.
1. Concept C16: Field task sequencing should be configured in order to
minimize damages or rework of some project elements, minimize scaffolding
needs, formwork used, or congestion of construction personnel, material and
equipment.
2. Concept C17: Innovation of a temporary construction materials/systems, or
implementing innovative ways of using available temporary construction
materials/systems, which have not been defined or limited by the design
drawings and technical specifications.
3. Concept C18: Innovation of new methods in using off-the-shelf hand tools,
or modification of the available tools, or origination of new hand tools that
reduce labour-intensity, increase mobility, safety or accessibility.
4. Concept C19: Innovative uses of new methods in using the available
equipment or modification of the available equipment to increase their
productivity.
5. Concept C20: Encouragement of the usage of constructor-optional
preassembly in order to increase the productivity, reduce the need for
27
scaffolding, or improve the project constructability under adverse weather
conditions.
6. Concept C21: Encouragement of the innovation of temporary facilities.
7. Concept C22: Contracts should not be awarded based on low bids only, but
by considering other project variables such as materials and time. Also, good
contractors should be considered for future construction works.
8. Concept C23: Evaluation documentation and feedback of the issues of the
constructability concepts used throughout the project.
These twenty three constructability enhancement concepts usher the ways in
which construction knowledge and experience may be used efficiently through the
process of engineered construction. The implementation of these concepts in a
project will greatly improve its constructability.
From the study that has been done by Rosli Mohamad Zin (2004), there are
eighteen concepts for the design phase which are:
1. Carry Out Thorough Investigation of the Site
Constructability is improved when the information gathered from site
investigation is thorough and complete. In this context CIRIA (“Buildability
: An Assessment” 1983) recommended that thorough site surveys (including
determination of ground conditions, underground hazards and other potential
problems) are essential to avoid risk of delays and design changes during
construction.
2. Design for Minimum Time Below Ground
Constructability is improved when the design minimize work below ground.
According to Adams (1989) the application of this concept is important
especially when the ground is hazardous, poor or wet. In those conditions the
28
speed and flow of the project can be increased when less work are carried our
below ground.
3. Design for Simply Assembly
Constructability is improved when designs are simplified and configured to
enable efficient construction. Designers should produce the simplest possible
details compatible with the overall requirements for the building, particular
element or group of elements. Adams (1989) mentioned that designers
should endeavor to produce the simplest possible details with the overall
requirements for the building, particular element, or group of elements. This
open the way to efficient, defect-free work that will satisfactorily perform its
end function.
4. Encourage Standardization/Repetition
O’Connors et al. (1987), stated that the standardization of components is
based on recognition that savings can be realized when the number of
variations of components is kept minimum. Many construction project
elements have potential for standardization. Building systems, material
types, construction details, dimensions and elevations may be standardized
for increased field efficiency.
5. Design for Preassembly and/or Modularization
Tatum et al. (1985) gave the following definitions:
Preassembly is a process by which various materials, prefabricated
components and/or equipment are joined together at a remote location
for subsequent installation as a unit. Preassembly often involves
decoupling sequential activities into parallel activities; and
A module is a product resulting from a series of remote assembly
operations; it is usually the largest transportable unit or component of
a facility. Modules may contain prefabricated components or
preassemblies and are usually constructed away from the job site.
29
6.
Analyze Accessibility of the Jobsite
The effect of accessibility can sometimes be quite serious such as delay in
progress, slowed productivity and increased damaged to completed work.
7. Employ Any Visualization Tools to Avoid Physical Interference
Constructability is improved when visualization tools are employed to
visualize any possibility of physical interference during construction.
Ghanah et al. (2000) highlighted that computer visualization allows
investigations to iron out difficulties that may occur before construction
commences on site.
8. Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
Particular attention should be given to the problems of fit which occur at the
interfaces between different products, methods of construction, materials and
method of manufacture, and suitable jointing methods should be adopted.
9. Investigate the Practical Sequence of Construction
Constructability is improved when adequate consideration of practical
sequence of construction is given. The method of construction of project
should encourage the most effective sequence of building operations. Simple
sequences enable each operation to be completed independently and without
interruption. The sequence should assist the coordination of trades and
minimized delay.
10. Plan to Avoid Damage to Work by Subsequent Operations
Constructability is improved when the damage to work by subsequent
operations is considered. The design should enable work to be carried out in
a workmanlike manner without risk of damage to adjacent finished elements
and with minimum requirement for special protection.
11. Consider Storage Requirement at the Jobsite
Constructability is improved when storage requirement is adequately
considered. Consideration should be given during the design stage to be
location of material storage and unloading facilities. The space occupied by
30
shoring, scaffolding, formwork, plant, compounds and workshops for
example can be considerable. Their efficient location and distribution is
necessary for good constructability. Poor consideration of storage
requirement may result in nearby streets to be closed, scaffolding and offices
may straddle the pavements and it may not possible to locate the tower crane
within the site.
12. Investigate the Impacts of Design on Safety During Construction
Constructability is improved when the impact of design on safety during
construction is adequately considered. The design produced by the designers
should enable the contractor to carry out their works in a safe like manner.
The design should be arranged so as to facilitate safe working in works such
as foundation and earth works, when materials and components are being
handled, and wherever traversing for access is necessary.
13. Design to Avoid Return Visit by Trade
Constructability is improved when the design enable a trade or specialist to
complete all its work at a work place with as few return visit as possible.
14. Design for the Skills and Resources Available
Constructability is improved when the technology of the design solution
matched with the skills and resources available. With regard to this
constructability concept Adams (1989) highlighted that any design is only
good as skills available to execute it, either off-site or on-site. Labour and
skills requirements vary between one project to another, between one locality
to another. Design must include a realistic assessment of the level of skill
likely to be available from appropriately chosen contractors and specialists.
15. Consider suitability of Designed Materials
Constructability is improved when suitable and robust materials are used.
According to Adams (1989), products and materials should be selected with
care, particularly, any which have not long been established and accepted
within the industry. They should be proven to be suitable for the use for
which they are selected. Products and materials should be selected which
31
utilize normal site assembly methods and sequences, with subsequent
operation and wear and tear in mind. Care should be taken to ensure that
manufacturer recommendations on handling, storage, application, assembly
and protection are complied with.
16. Provide detail and clear Design Information
Constructability is improved when thorough and clear presentation of design
information before the start of construction. Sufficient time and resources
must be allowed for this in design budget. Complete project information
should be planned and coordinated to suit the construction process and to
facilitate the best possible communication and understanding on site.
According to Ghanah et al. (2000) communication between designers and
other participants in construction project are normally performed using
traditional methods i.e. paper based drawing, schedule, written statements etc.
In order to improve constructability, priority must be given on the reliability
of the information communicated through these methods. Therefore, the
accuracy, understandability and clarity of information generated during the
design process must be checked at all times.
17. Design for Early Enclosure
Constructability is improved when the design enables early enclosure of the
constructed building. CIRIA (“Buildability: An Assessment” 1983) suggests
that the construction and detailing of a building shell, including the roof
(whether framed or loading bearing construction), should facilitate the
enclosure of the building at the earliest possible stage. Following operations
can then commence early in the programmed, and they can be carried out
without hindrance from weather.
18. Consider Adverse Weather Effect in Selecting Materials or Construction
Methods
Constructability is improved when the effect of adverse weather is
considered. Project constructed in localities where weather conditions are
adverse presents a great challenge to both the designer and the constructor.
32
Designers should investigate ways in which the exposure to temperatures
extreme and the effects of rain may be minimized.
2.6 Design Phase Constructability Concepts for the Highway Projects
Among many of participants involved in the project, the designers are
expected to play the central role for constructability improvement (Hassan, 1997).
Designers are seen to have significant roles as they are responsible for most technical
problems which arise during project design, in the construction and commissioning
of the project. Madelsohn (1997) seemed to agree with the view that designers do
not give enough consideration to the problems that contractors had to face during
construction. In an article “The Constructability Review Process: A Constructor’s
Perspective”, Madelsohn (1997) highlighted that 75% problems in the field are
generated in the design phase.
Fisher and Rajan (1996) described the constructability of designs as the
integration of construction knowledge, resources, technology, and experience into
the engineering and design of a project. Discovering and addressing design errors
and omission in a timely manner is critical for short project durations (Ford and
Sterman 1998; Cooper 1993). Constructability problems are one type of these errors
and omissions. Constructability problems that are not identified and addressed
during design can have a negative impact on project schedule performance by
slowing construction operations and generating unplanned delays.
This impact was cited as an important issue for highway projects in a
National Cooperative Highway Research Program project (Russel and Anderson,
2000). The same research identified “constructability” and “methods to minimize
project duration” as two several critical issues necessary for improving construction
33
and the quality of highway projects. Therefore, reviewing designs and specifications
to identify and address constructability issues is a primary means of reducing
highway project durations. An example highlighted by Mendelsohn (1999)
illustrates the potential impacts of addressing constructability problems during
highway project design:
A bridge was to be designed over four lanes of divided highway. The
original design used large precast girders that spanned from abutment to abutment.
Constructability review identified that, because of ground conditions and traffic,
locating cranes of sufficient capacity on the median strip to place the girders called
for in the design would be very difficult and time consuming. As an alternative, a
pier was designed and built on the median at midspan, allowing the use of shorter,
lighter, and shallower girders that could be handled by a smaller crane. Additionally,
the reduced girder depth permitted a lower grade to the bridge deck, thereby reducing
earth filling requirements at the approaches. The faster crane mobilization, handling
of smaller girders, reduced interruptions to traffic, and less fill work shortened the
project duration by three months. The cost savings paid for the additional mid-span
pier.
Many of the design decisions made early in the design process affect the
construction of the project. Consequently, construction expertise is often
incorporated in the design process to improve the constructability of the design.
In 2.5, the constructability concepts that are applicable in all phases of
construction project were described. It can be observed that during the design phase
the concepts developed by Rosli Mohamad Zin (2004) are more thorough with
respect to ease of construction. It was discovered from his study that 9.2% of
respondent were involved in highway projects. The findings indicate that
constructability concepts for buildings projects were almost similar to the highway
projects. The following are detail description of the constructability concepts
identified by Rosli Mohamad Zin (2004).
34
2.6.1
Carry Out Thorough Investigation of the Site
Constructability is improved when the information gathered from site
investigation is thorough and complete. In this context CIRIA (“Buildability : An
Assessment” 1983) recommended that thorough site surveys (including
determination of ground conditions, underground hazards and other potential
problems) are essential to avoid risk of delays and design changes during
construction.
An example of application of this concept is in bridge construction as
highlighted by Nima et.al (2002). In this project, the difficulties of launching the
bridge girders was not properly dealt with during the early phases of the project, as
the contractor faced big difficulties in launching numerous girders along the elevated
structure. The elevated structure passed through the town, and the road reserve width
inside the town was not similar to that outside the town due to land acquisition cost
and some social reasons. Thus, the existing buildings inside the town hampered the
lifting of the girders to their final position. Figure 2.4 illustrates the normal process
of launching the girders. In contrast, Figure 2.5 shows the site at which the
contractor faced the problem. Panel A in Figure 2.5 shows that the existing town
market and its fence are very close to the elevated highway.
Accordingly, there was not enough room for the cranes to launch the girders.
In order to solve this problem, the contractor dismantled the fence, launched the
girders, and rebuilt the fence. Panel B in Figure 2.5 shows a span in another location
of the project, in which the launching was impeded by two buildings that could not
be dismantled due to economic reasons and non agreement of their owners. This
problem was dealt with only after reaching the critical step of launching the girders.
It was solved by transporting the cranes to the adjacent constructed spans, and from
this position the launching was done after causing work schedule delays. The reason
for this problem was that there was no construction input to the major construction
methods and the site layouts during the conceptual planning phase.
35
Figure 2.4: Process of launching girder for elevated structure (Adapted from Nima,
2002)
Figure 2.5: Problems faced during launching of some girders (Adapted from Nima,
2002)
36
In other case as experienced by Nima (2004) in highway projects, especially
in rural areas, the problem of site layouts is less severe than that of projects in
metropolitan areas. In metropolitan area, an adequate space was necessary for
casting, pre stressing, curing, and storing the girders (up to 35 m long) until the time
of erection. This requirement was not thought of until after the construction was
resumed. The contractor was fortunate to find a vacant lot of land that was available
for rent, adjacent to the construction site, which then was used for pre casting and
storing these members. Sometimes, the acquired land for the project site was greater
than what the actual structures and the civil engineering works required. Therefore,
this concept has to study thoroughly, during the design phase.
2.6.2
Design for Minimum Time Below Ground
Constructability is improved when the design minimize work below ground.
According to Adams (1989) the application of this concept is important especially
when the ground is hazardous, poor or wet. In those conditions the speed and flow
of the project can be increased when less work are carried out below ground.
An example of problem related to this concepts as shown in Figure 2.6 and
Figure 2.7. Figure 2.6 shows the plan and a cross section of a part of the elevated
highway, and Figure 2.7 illustrates the problem and the consequences of the
difficulty of compacting the soil and sub base between two pile caps after the start-up
of the project. This was due to the lack of enough space for traditional compacting
equipment to do the compaction properly.
37
Figure 2.6: Details of elevated highway (Adapted from Nima, 2002)
38
Figure 2.7: Problem of compaction and result after project start-up (Adapted from Nima,
2002)
39
2.6.3
Design for Simply Assembly
Constructability is improved when designs are simplified and configured to
enable efficient construction. Designers should produce the simplest possible details
compatible with the overall requirements for the building, particular element or
group of elements. Adams (1989) mentioned that designers should endeavor to
produce the simplest possible details with the overall requirements for the building,
particular element, or group of elements. This open the way to efficient, defect-free
work that will satisfactorily perform its end function.
The implementation of this concept in the highway project was accomplished
by simplifying the design of the piers and decks. Some projects with the major
structure consisted of repetitive detailing had a good potential for detailing
simplification.
As was discussed by Nima et al. (1999) aesthetics is one of the main project
objectives, which frequently overrides the constructability requirements. For this
reason, implementing this concept was preserved for the approaches only and
constituted a high percentage of the total cost of the project. The following
techniques and measures were applied:
• Using the prefabricated post-tensioned I-Beams for the decks reduced the
usage of scaffolding,
• Decreasing the number of elements, and
• Using the prefabricated girders to reduce construction task
interdependencies.
For example, work on the cast-in-elements could proceed while fabricating
the girders off-site is in progress. From the above discussion it is clear that designs
can be simplified and configured to enable efficient construction through different
40
means and methods. Also, one might properly suggest that it is wise to seek opinion
from experienced construction personnel on a continuous basis to review the designs
to ensure that this constructability principle is effectively implemented.
2.6.4
Encourage Standardization/Repetition
O’Connors et al. (1987), stated that the standardization of components is
based on recognition that savings can be realized when the number of variations of
components is kept minimum. Many construction project elements have potential
for standardization. Building systems, material types, construction details,
dimensions and elevations may be standardized for increased field efficiency.
This concept supports standardization of the project’s components. The
consultant made good use of this concept by standardizing the majority of the
project’s elements. Examples include the piers, crossbeams, and decks. The
standardization of girders was used for the approach ramps. All elements including,
pile types, pier columns, pier cross beams, girders, parapets, handrails, guardrails and
drainage system can be standardized.
2.6.5
Design for Preassembly and/or Modularization
Tatum et al., (1985) gave the following definitions:
•
Preassembly is a process by which various materials, prefabricated components
and/or equipment are joined together at a remote location for subsequent
41
installation as a unit. Preassembly often involves decoupling sequential activities
into parallel activities; and
•
A module is a product resulting from a series of remote assembly operations; it is
usually the largest transportable unit or component of a facility. Modules may
contain prefabricated components or preassemblies and are usually constructed
away from the job site.
This concept advocated using prefabrication, preassembly, and
modularization. In order to apply this constructability concept, some of highway
projects used of pre stressed M-beams and U-beams for the spans that made up the
elevated highway and post tensioned I-beams for the intersections with the town
roads and railway tracks. However, as O’Connor et al. (1987) warned, lifting
limitations and delivery route restrictions should be studied when planning to
implement this concept.
From experience by Nima (2004) in his cable stayed project, this concept
advocates using modules and preassemblies in design. The usage of the
prefabricated post-tensioned I-beams was an application of this concept.
Furthermore, the spun piles were used for the same portion, i.e., the approach ramps.
Those two elements made up a high percentage of the total cost of the project. By
using these two elements, many constructability concepts were applied.
Consequently the quality, cost, and schedule were optimized.
2.6.6
Analyze Accessibility of the Jobsite
The effect of accessibility can sometimes be quite serious such as delay in
progress, slowed productivity and increased damaged to completed work. This
concept highly promotes accessibility to enhance project constructability. The road
42
reserve width inside the town was narrower, which made the contractor face many
accessibility problems that caused delays in progress and decreased productivity.
2.6.7
Employ Any Visualization Tools to Avoid Physical Interference
Constructability is improved when visualization tools are employed to
visualize any possibility of physical interference during construction. Ghanah et al.,
(2000) highlighted that computer visualization allows investigations to iron out
difficulties that may occur before construction commences on site.
This concept advocates the consultants to employ the capabilities of advanced
information technology. This concept was well used during the design and
preparation of the plans. Examples of application of this concept include using the
internet and developing models (software) to test the structural behavior in the early
stages of the conceptual design.
2.6.8
Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
Particular attention should be given to the problems of fit which occur at the
interfaces between different products, methods of construction, materials and method
of manufacture, and suitable jointing methods should be adopted.
43
2.6.9
Investigate the Practical Sequence of Construction
Constructability is improved when adequate consideration of practical
sequence of construction is given. The method of construction of project should
encourage the most effective sequence of building operations. Simple sequences
enable each operation to be completed independently and without interruption. The
sequence should assist the coordination of trades and minimized delay.
According to this concept, construction sequence should generally dictate the
procurement and engineering sequences. The schedules for design and procurement
activities should be driven by the needs of the construction. Thus, a construction
schedule must be developed before design and procurement schedules are initiated
(CII 1987, 1993).
2.6.10 Plan to Avoid Damage to Work by Subsequent Operations
Constructability is improved when the damage to work by subsequent
operations is considered. The design should enable work to be carried out in a
workmanlike manner without risk of damage to adjacent finished elements and with
minimum requirement for special protection.
44
2.6.11 Consider Storage Requirement at the Jobsite
Constructability is improved when storage requirement is adequately
considered. Consideration should be given during the design stage to be location of
material storage and unloading facilities. The space occupied by shoring,
scaffolding, formwork, plant, compounds and workshops for example can be
considerable. Their efficient location and distribution is necessary for good
constructability. Poor consideration of storage requirement may result in nearby
streets to be closed, scaffolding and offices may straddle the pavements and it may
not possible to locate the tower crane within the site.
2.6.12 Investigate the Impacts of Design on Safety During Construction
Constructability is improved when the impact of design on safety during
construction is adequately considered. The design produced by the designers should
enable the contractor to carry out their works in a safe like manner. The design
should be arranged so as to facilitate safe working in works such as foundation and
earth works, when materials and components are being handled, and wherever
traversing for access is necessary.
2.6.13 Design to Avoid Return Visit by Trade
Constructability is improved when the design enable a trade or specialist to
complete all its work at a work place with as few return visit as possible.
45
As for this concept, Boyce (1991) proposed using the ‘‘performance type
specification approach.’’ This can be achieved by selecting a vendor with a good
reputation and experience in the required specialization who will supply the item
with a guarantee. This approach was used for many items in the project rather than
implementing ‘‘gold-plated’’ off-the-shelf specifications that O’Connor and Miller
(1994) considered one of the barriers to constructability implementation. The best
example is the elastomeric bearing pads for the viaduct and the approach ramps.
2.6.14 Design for the Skills and Resources Available
Constructability is improved when the technology of the design solution
matched with the skills and resources available. With regard to this constructability
concept Adams (1989) highlighted that any design is only good as skills available to
execute it, either off-site or on-site. Labour and skills requirements vary between
one projects to another, between one locality to another. Design must include a
realistic assessment of the level of skill likely to be available from appropriately
chosen contractors and specialists.
2.6.15 Consider Suitability of Designed Materials
Constructability is improved when suitable and robust materials are used.
According to Adams (1989), products and materials should be selected with care,
particularly, any which have not long been established and accepted within the
industry. They should be proven to be suitable for the use for which they are
selected. Products and materials should be selected which utilize normal site
assembly methods and sequences, with subsequent operation and wear and tear in
46
mind. Care should be taken to ensure that manufacturer recommendations on
handling, storage, application, assembly and protection are complied with.
In one case study by Brasic (2004), the composite single steel box
girder/concrete deck bridges are not commonly constructed in Canada. On this
project, they were implemented for the single lane, high-speed ramps connecting the
existing highway system with the approach roads to the New Terminal One building.
The single steel box girder bridge type was adopted as the optimal solution
compared to other structure types, for specific locations. The governing criteria for
type selection were complex geometry and deck width, feasibility, the need to
maintain traffic under the bridges throughout construction, and limited space under
the bridges to provide false work supports. The number of spans varies between four
and nine with the maximum spans up to 56 meters in length. Total length of bridges
varies between 164 and 371 meters. Road geometry constraints resulted in minimum
horizontal curve radius of 148.5 meters and maximum 6% grades. The unique
details used in these bridges present an alternative, cost-effective approach in
meeting each of the Client’s needs using innovative detailing and appropriate
construction technology. The structures were tendered approximately 15% below the
engineer’s estimates.
2.6.16 Provide Detail and Clear Design Information
Constructability is improved when thorough and clear presentation of design
information before the start of construction. Sufficient time and resources must be
allowed for this in design budget. Complete project information should be planned
and coordinated to suit the construction process and to facilitate the best possible
communication and understanding on site. According to Ghanah et al., (2000)
communication between designers and other participants in construction project are
normally performed using traditional methods i.e. paper based drawing, schedule,
47
written statements etc. In order to improve constructability, priority must be given
on the reliability of the information communicated through these methods.
Therefore, the accuracy, understandability and clarity of information generated
during the design process must be checked at all times.
2.6.17 Design for Early Enclosure
Constructability is improved when the design enables early enclosure of the
constructed building. CIRIA (“Buildability: An Assessment” 1983) suggests that the
construction and detailing of a building shell, including the roof (whether framed or
loading bearing construction), should facilitate the enclosure of the building at the
earliest possible stage. Following operations can then commence early in the
programmed, and they can be carried out without hindrance from weather.
2.6.18 Consider Adverse Weather Effect in Selecting Materials or Construction
Methods
Constructability is improved when the effect of adverse weather is
considered. Project constructed in localities where weather conditions are adverse
presents a great challenge to both the designer and the constructor. Designers should
investigate ways in which the exposure to temperatures extreme and the effects of
rain may be minimized.
This concept encourages facilitating construction under adverse weather
conditions through design. This concept was practiced through using the pre cast
48
units for the girders and drainage systems for roadsides and manholes. The pre cast
elements were not damaged by rain when compared with the cast-in situ type of
construction. Moreover, using the precast drainage systems helped in discharging
rainwater during rainy weather.
While preparing his case study about Kuala Lumpur International Airport,
Stevens (1997) discovered four major threats confronting the contractors and
subcontractors who were participating in this giant project. One of those threats was
the adverse weather condition. Once again, using prefabricated spun piles and
girders met the requirements of this concept.
2.7 Summary
Through the literature survey on constructability in construction projects, the
following summaries are made:
(i)
The specific constructability issues from the perspective of agencies, design
firms and construction contractors, are applicable to all types of construction
but some additional aspect such as traffic controls have to be determined in
highway projects.
(ii)
The applications of constructability concepts can be entirely applied in
highway project process. But, maximum benefit of constructability can be
achieved in the early phases of the project such as conceptual planning and
design phases.
49
(iii)
The constructability concepts proposed by the various researchers are
applicable to highway construction projects. However, with respect to the design
phase the constructability concepts identified by Rosli Mohamad Zin (2004) is found
to be most thorough an appropriate. The concepts are:
• Carry out thorough investigation of the site;
• Design for minimum time below ground;
• Design for simple assembly;
• Encourage standardisation/repetition;
• Design for pre-fabrication, pre-assembly or modularization;
• Analyse accessibility of the jobsite;
• Employ any visualisation tools such to avoid physical interference;
• Investigate any unsuspected unrealistic or incompatible tolerances;
• Investigate the practical sequence of construction;
• Plan to avoid damage to work by subsequent operations;
• Consider storage requirement at the jobsite;
• Investigate the impacts of design on safety during construction;
• Design to avoid return visit by trade;
• Design for the skills available;
• Consider suitability of designed materials;
• Provide detail and clear design information;
• Design for early enclosure; and
• Consider adverse weather effect in selecting materials or construction
methods
CHAPTER 3
RESEARCH METHODOLOGY
3.1
Introduction
Various steps can be adopted to fulfill the objectives of this study. The
research methodology for this research includes discussion on method of data
collection, the approach used, research consideration such as design of questionnaire
and data analysis.
3.2
Research Process
The research process involves literature review to gather information on the
subject, development of questionnaire to establish the level of importance and
application of constructability concepts from data analysis.
51
Data have been collected in Johor Bharu, Terengganu and Kelantan. Data
collection is made through questionnaire to be filled and submit back to the
researcher. After that data have been analyzed using Statistical Package for Science
Social 11.0 (SPSS).
3.3
Determining the Research Objectives
The main objective of this research is to identify the constructability concepts
in construction. The other objectives are to identify the level of application and
importance of constructability concepts in design phase for highway project in
Malaysia. In determining the research objectives, a review process is undertaken to
determine the suitable methodology in terms of its feasibility, achievability to
achievable data collection, and its analysis.
52
3.4
Steps in Methodology
CONCEPTUALIZATION
LITERATURE REVIEW
QUESTIONNAIRE
DATA ANALYSIS
CONCLUSION
Figure 3.1: Steps in Methodology
3.4.1
Conceptualization
Conceptualization is aimed at understanding the importance and basics of the
work to be carried out. In this stage, the objectives of the project will be set and the
problem will be stated. After that, literature review will be undertaken.
53
3.4.2
Literature Review
The main aim in carrying out the literature review is to gather information on
the topic. Former studies on the issues will be analyzed the scope of the topic.
Relevant articles, journals, paperwork, thesis and books have been looking for. Few
book and thesis are related to the topic, journal papers and proceeding also help to
get more information.
3.4.3
Questionnaire
A four and five scale Likert Type questionnaire has been used as research
tools for collecting data concerning opinions and attitudes of experienced engineers
in constructability. Likert Scale is a widely use instruments in measuring opinions,
beliefs and attitudes (Devellis, 1991).
The final form of the questionnaire consisted of four parts, as shown in
Figure 3.2. The first part consists of the background of the respondent, such as his
engineering field, years of experience, and etc. The second part consist of 18 Likerttype five scale questions, each presenting one constructability concept in design
phase in highway project, and each requiring only one choice to be made out of five;
Very Important, Important, Moderate, Little Important and Not Important.
The third part was formulated to collect information regarding the rate of
application of each constructability concept in design phase in highway project in
Malaysia. The respondents were asked to evaluate the degree of application of
design concept, by choosing one of the following 18 Likert type four scale questions
54
responses; High Application, Medium Application, Little Application and Not
applied at all.
The fourth part consists of one free question. The objective of the question is
to have ideas of the problems faced by engineers and experienced highway
construction personnel.
Questionnaire has been done with the people who are expertise in highway
projects. The researchers produce 70 questionnaires then distributed to the potential
respondent in Kelantan, Terengganu and Johor (Johor Bharu). The questionnaires
were distributed to professionals in fifty organizations registered with Institution of
Engineers Malaysia (IEM) and were selected randomly that represent the clients,
contractors and consultant.
55
Start
Part One: Demographics
7 Questions
Part Two: Degree of Importance
18 Questions
Part Three: Degree of Application
18 Questions
Part Four: Feedback
1 Question
End
Figure 3.2: Questionnaire Flow Chart
56
3.4.4
Analysis
The collected data were analyzed by using the Statistical for Social Science
(SPSS) program version 11.0. Frequency and average index method is adopted for
analysis. The frequency and the percentage will be represented in the form of table
and pie chart.
3.4.4.1 Average Index
In part two and part three of the questionnaire, the respondents are asked to
evaluate the level of importance and application of constructability concepts in
design phase in highway projects in Malaysia. From the frequency analysis that have
been done, the frequency value will be used in determining the average index value.
Refer to Odeh and Batainneh, 2001, the average index value will be
calculated using this formula:
Average index = ∑ (aX), where X = n / N
a = constant expressing the weight given
N = total number of respondent
n = variable expressing the frequency of respondent
The classification of the rating scales proposed by Abd. Majid (1997) are as
follows:
57
•
“Very Satisfy”
1.00 < Average Index < 1.50
•
“Satisfy”
1.50 ≤ Average Index < 2.50
•
“Fair”
2.50 ≤ Average Index < 3.50
•
“Less Satisfy”
3.50 ≤ Average Index < 4.50
•
“Not Satisfy”
4.50 ≤ Average Index < 5.00
3.5 Development of Guidelines
From the study and analysis, Design Phase Constructability Improvement
Guidelines for Malaysian Highway Projects have been developed after an expert
interview between two experience personnel from the highway projects for
validation.
CHAPTER 4
DATA ANALYSIS AND DISCUSSION
4.1
Introduction
Data analysis was discussed for 35 questionnaires submitted. The questions
asking included the three parts which are:
i.
Part One: Demographics
Respondent’s background which included information about organization,
education, field of specialization, position in the company, designing and
working experience in highway projects.
ii.
Part Two: Opinions
Respondent’s opinions about the degree of importance of the constructability
concepts in the design phase in highway projects.
59
iii.
Part Three: Opinions
Respondent’s opinions about the degree of application of the constructability
concepts in the design phase in highway projects.
iv.
4.2
Part Four: Feedback
Respondent’s Background
Amongst the four parts included in the questionnaires, part one, which is
demographic, is the only one referring to the respondent background.
4.2.1
Type of Organization
Referring to Table 4.1 and Figure 4.1, 2.9% of the respondents (1 person) an
owner, 48.6% (17 persons) works in consultant firms, 31.4% (11 persons) work with
contractor and 17.1% (6 persons) in other type of organization like developer and etc.
Table 4.1: Type of Organization
Owner
Consultant
Contractor
Others
Total
Frequency
Percent
1
17
11
6
35
2.9
48.6
31.4
17.1
100.0
Valid Percent
(%)
2.9
48.6
31.4
17.1
100.0
Cumulative
Percent (%)
2.9
51.4
82.9
100.0
60
Others
17%
Contractor
31%
Owner
3%
Consultant
49%
Figure 4.1: Percentage of type of organization
4.2.2
Level of Education
The level of education among the respondent in this study are from 60% (21
persons) have B.Sc, 17.1% (6 persons) are engineers or designers with M.Sc
Qualification. The others qualifications are from PhD to Diploma in Civil Engineering
request 22.9% (8 persons) which can refer to Table 4.2 and Figure 4.2 below.
61
Table 4.2: Level of Education
B.Sc
M.Sc
Others
Total
Frequency
Percent
21
6
8
35
60.0
17.1
22.9
100.0
Valid Percent
(%)
60.0
17.1
22.9
100.0
Cumulative
Percent (%)
60.0
77.1
100.0
Others
23%
M.Sc
17%
B.Sc
60%
Figure 4.2: Percentage of level of education
4.2.3 Field Of Specialization
Most of the respondent, 80% (28 persons) are civil engineers. Beside that, one
respondent is Mechanical Engineer (2.9%). The others including Quantity Surveyor and
Building personnel cover 17.1% or 6 persons. The proportioning is shown in the Table
4.3 and Figure 4.3.
62
Table 4.3: Field Of Specialization
Civil Engineer
Mechanical Eng
Others
Total
Frequency
Percent
28
1
6
35
80.0
2.9
17.1
100.0
Valid Percent
(%)
80.0
2.9
17.1
100.0
Cumulative
Percent (%)
80.0
82.9
100.0
Others
17%
Mechanical
Eng
3%
Civil Engineer
80%
Figure 4.3: Percentage of field of specialization
4.2.4 Position in Organization
Table 4.4 and Figure 4.4 show the position holding by the respondent. 20% (7
persons) of the respondents are designers in their company or organization, 2.9% or 1
person is planner. Quantity surveyors are 14.3% or 5 persons of the respondents. The
others site engineer, project manager, site supervisor, and etc are 62.9% or 22 persons.
63
Table 4.4: Position in Organization
Designer
Planner
Quantity Surveyor
Others
Total
Frequency
Percent
7
1
5
22
35
20.0
2.9
14.3
62.9
100.0
Valid Percent
(%)
20.0
2.9
14.3
62.9
100.0
Cumulative
Percent (%)
20.0
22.9
37.1
100.0
Designer
20%
Planner
3%
Others
63%
Quantity
Surveyor
14%
Figure 4.4: Percentage of Position in Organization
4.2.5 Number of Years Practiced in Designing in Highway Projects
The highest percentages, 88.6% or 31 persons of the respondents have 0-5 years
of experience. This is because most of the highway projects are under the supervision of
civil engineers. Generally, in an organization the same persons are in charge of both
buildings and highway projects. But 5.7% (2 persons) of respondents have 6-10 years of
experiences in designing highway projects. The respondent with PhD qualification is
64
the only one who has more than 20 years of experience as shown in Table 4.5 and Figure
4.5.
Table 4.5: Number of Years Practiced in Designing in Highway Projects
0-5 Years
6-10 Years
11-15 Years
More than 20 Years
Total
Frequency
Percent
31
2
1
1
35
88.6
5.7
2.9
2.9
100.0
6-10 Years
5.7%
Valid Percent
(%)
88.6
5.7
2.9
2.9
100.0
Cumulative
Percent (%)
88.6
94.3
97.1
100.0
More than 20
Years
2.9%
11-15 Years
2.9%
0-5 Years
88.6%
Figure 4.5: Percentage of Number of Years Practiced in Designing In Highway Projects
4.2.6 Number of Years Practiced in Working in Highway Projects
The numbers of years practiced in working in highway projects as represented in
Table 4.6 and Figure 4.6 shows that 91% (32 persons) the respondents have 0-5 years of
65
experience is 91.4% (32 persons), 2.9% (1 person) have 6-10 years, 2.9 %( 1 person)
between 11-15 years and 2.9% (1 person) have more than 20 years.
Table 4.6: Number of Years Practiced in Working in Highway Projects
0-5 Years
6-10 Years
11-15 Years
More than 20 Years
Total
Frequency
Percent
32
1
1
1
35
91.4
2.9
2.9
2.9
100.0
6-10 Years
3%
Valid
Percent (%)
91.4
2.9
2.9
2.9
100.0
Cumulative
Percent (%)
91.4
94.3
97.1
100.0
More than 20
Years
3%
11-15 Years
3%
0-5 Years
91%
Figure 4.6: Number of Years Practiced in Working in Highway Projects
66
4.3
Level Of Importance of Constructability Concepts
The researcher will use two types of analysis; frequency analysis and average
index.
4.3.1
Frequency Analysis
Using the result of the data collected, the SPSS software is using to analyze the
frequency analysis.
4.3.1.1 Carry out Thorough Investigation of the Site
Referring to the Table 4.7 below, 77.1% of the respondent agreed that the first
concept of constructability which is ‘Carry out Thorough Investigation of the Site’ is
“very important” in the design phase in highway projects in Malaysia. For 20%, this
concept is “important”, and only 1 person judges it “moderate”.
Table 4.7: Carry out Thorough Investigation of the Site
Moderate
Important
Very Important
Total
Frequency
Percent
1
7
27
35
2.9
20.0
77.1
100.0
Valid Percent
(%)
2.9
20.0
77.1
100.0
Cumulative
Percent (%)
2.9
22.9
100.0
67
4.3.1.2 Provide Detail and Clear Design Information
For the second concept, Table 4.8 shows that 57.1% of the respondents agreed
that ‘Provide Detail and Clear Design Information’ is “very important” while 42.9%
agreed that this concept is “important”.
Table 4.8: Provide Detail and Clear Design Information
Important
Very Important
Total
Frequency
Percent
15
20
35
42.9
57.1
100.0
Valid Percent
(%)
42.9
57.1
100.0
Cumulative
Percent (%)
42.9
100.0
4.3.1.3 Analyze Accessibility of the Jobsite
‘Analyze Accessibility of the Jobsite’ is also a key for constructability in design
phase for highway projects. Table 4.9 shows that 54.3% of the respondent agreed that
this concept is “very important”, 42.9% judged it “important” and 2.9% judged it
“moderate”.
Table 4.9: Analyze Accessibility of the Jobsite
Moderate
Important
Very Important
Total
Frequency
Percent
1
15
19
35
2.9
42.9
54.3
100.0
Valid Percent
(%)
2.9
42.9
54.3
100.0
Cumulative
Percent (%)
2.9
45.7
100.0
68
4.3.1.4 Investigate the Impacts of Design on Safety during Construction
Table 4.10 shows that the constructability concept that is ‘Investigate the
Impacts of Design on Safety during Construction’ is also important in design phase.
54.3% of the respondent found it “very important”, 28.6% as “important”, 14.3%
“moderate” and 1% “little important”.
Table 4.10: Investigate the Impacts of Design on Safety during Construction
Little Important
Moderate
Important
Very Important
Total
Frequency
Percent
1
5
10
19
35
2.9
14.3
28.6
54.3
100.0
Valid Percent
(%)
2.9
14.3
28.6
54.3
100.0
Cumulative
Percent (%)
2.9
17.1
45.7
100.0
4.3.1.5 Consider Suitability of Designed Materials
The other constructability concept that must be considered while designing is
‘Consider Suitability of Designed Materials’. Table 4.11 below shows that this concept
is “very important” for 42.9%, “important” for 42.9% and the other 14.3% judged it
“moderate”.
69
Table 4.11: Consider Suitability of Designed Materials
Moderate
Important
Very Important
Total
Frequency
Percent
5
15
15
35
14.3
42.9
42.9
100.0
Valid Percent
(%)
14.3
42.9
42.9
100.0
Cumulative
Percent (%)
14.3
57.1
100.0
4.3.1.6 Investigate the Practical Sequence of Construction
‘Investigate the Practical Sequence of Construction’ is one of the constructability
concepts that need to be beware of by the designer in design process. 45.7% of the
respondent judges it “very important”, 37.1% as “important”, 14.3% as “moderate” and
the other 2.9% judged it of “little important”, as shown in Table 4.12 below.
Table 4.12: Investigate the Practical Sequence of Construction
Little Important
Moderate
Important
Very Important
Total
Frequency
Percent
1
5
13
16
35
2.9
14.3
37.1
45.7
100.0
Valid
Percent (%)
2.9
14.3
37.1
45.7
100.0
Cumulative
Percent (%)
2.9
17.1
54.3
100.0
70
4.3.1.7 Consider Adverse Weather Effect in Selecting Materials or Construction
Methods
Table 4.13 below shows that 17.1% of the respondents ‘Consider Adverse
Weather Effect in Selecting Materials or Construction Methods’ is “very important”. It
is “important” for 62.9%, 17.1% for “moderate” and 2.9% for “little important”.
Table 4.13: Consider Adverse Weather Effect in Selecting Materials or Construction
Methods
Little Important
Moderate
Important
Very Important
Total
Frequency
Percent
1
6
22
6
35
2.9
17.1
62.9
17.1
100.0
Valid Percent
(%)
2.9
17.1
62.9
17.1
100.0
Cumulative
Percent (%)
2.9
20.0
82.9
100.0
4.3.1.8 Plan to Avoid Damage to Work by Subsequent Operations
Table 4.14 shows that 28.6% of the respondents think that ‘Plan to Avoid
Damage to Work by Subsequent Operations’ is “very important”, while 45.7% of them
responded that it is “important”, and 25.7% judge it as “moderate”.
71
Table 4.14: Plan to Avoid Damage to Work by Subsequent Operations
Moderate
Important
Very Important
Total
Frequency
Percent
9
16
10
35
25.7
45.7
28.6
100.0
Valid Percent
(%)
25.7
45.7
28.6
100.0
Cumulative
Percent (%)
25.7
71.4
100.0
4.3.1.9 Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
‘Investigate Any Unsuspected Unrealistic or Incompatible Tolerances’ is also
one of the constructability concepts that have to be considered in design stages in
highway projects in Malaysia and it supported by the respondent opinion in Table 4.15.
28.6% of the respondents respond it as “very important”, 45.7 as “important” and the
other 25.7% respond it as “moderate”.
Table 4.15: Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
Moderate
Important
Very Important
Total
Frequency
Percent
9
16
10
35
25.7
45.7
28.6
100.0
Valid Percent
(%)
25.7
45.7
28.6
100.0
Cumulative
Percent (%)
25.7
71.4
100.0
72
4.3.1.10 Design for the Skills and Resources Available
The result in Table 4.16 shows that 34.3% of the respondent agree that the
concept ‘Design for the Skills and Resources Available’ is “very important”, 34.3%
judged it “important”, 25.7% as “moderate” and the other 2% as “little important”.
Table 4.16: Design for the Skills and Resources Available
Little Important
Moderate
Important
Very Important
Total
Frequency
Percent
2
9
12
12
35
5.7
25.7
34.3
34.3
100.0
Valid Percent
(%)
5.7
25.7
34.3
34.3
100.0
Cumulative
Percent (%)
5.7
31.4
65.7
100.0
4.3.1.11 Consider Storage Requirement at the Jobsite
Table 4.17 below shows that 17.1% of the respondents agree that the
constructability concept ‘Consider Storage Requirement at the Jobsite’ is “very
important”, 60% as “important” and 22.9% as “moderate”.
Table 4.17: Consider Storage Requirement at the Jobsite
Moderate
Important
Very Important
Total
Frequency
Percent
8
21
6
35
22.9
60.0
17.1
100.0
Valid Percent
(%)
22.9
60.0
17.1
100.0
Cumulative
Percent (%)
22.9
82.9
100.0
73
4.3.1.12 Design for Minimum Time Below Ground
From the Table 4.18 below, it can be noticed that 22.9% of the respondent agreed
that ‘Design for Minimum Time below Ground’ is “very important”, 37.1% think it is
“important” and 40% “moderate”.
Table 4.18: Design for Minimum Time below Ground
Moderate
Important
Very Important
Total
Frequency
Percent
14
13
8
35
40.0
37.1
22.9
100.0
Valid Percent
(%)
40.0
37.1
22.9
100.0
Cumulative
Percent (%)
40.0
77.1
100.0
4.3.1.13 Design for Early Enclosure
From the Table 4.19 below, the constructability concept which is ‘Design for
Early Enclosure’ is “very important” for 20% of the respondents, 48.6% for “important”,
20% for “moderate” and 11.4% for “little important”.
Table 4.19: Design for Early Enclosure
Little Important
Moderate
Important
Very Important
Total
Frequency
Percent
4
7
17
7
35
11.4
20.0
48.6
20.0
100.0
Valid
Percent (%)
11.4
20.0
48.6
20.0
100.0
Cumulative
Percent (%)
11.4
31.4
80.0
100.0
74
4.3.1.14 Encourage Standardization/Repetition
The study shows that the respondent opinion is as follows; 11.4% of them
respond that ‘Encourage Standardization/Repetition’ is “very important”, more than half
of them 60% respond it is “important”, and 28.6% of them respond it is “moderate”.
Table 4.20: Encourage Standardization/Repetition
Frequency
Percent
Valid Percent
(%)
10
21
4
35
28.6
60.0
11.4
100.0
28.6
60.0
11.4
100.0
Moderate
Important
Very Important
Total
Cumulative
Percent
(%)
28.6
88.6
100.0
4.3.1.15 Employ Any Visualization Tools to Avoid Physical Interference
From the survey that have been done, it can be indicated that, 14.3% of the
respondent agreed that ‘Employ Any Visualization Tools to Avoid Physical
Interference’ is a “very important” constructability concept in design phase in highway
projects. 51.4% agreed that it is “important”, 28.6% respond it as “moderate” and 5.7%
respond it as “little important”.
Table 4.21: Employ Any Visualization Tools to Avoid Physical Interference
Little Important
Moderate
Important
Very Important
Total
Frequency
Percent
2
10
18
5
35
5.7
28.6
51.4
14.3
100.0
Valid Percent
(%)
5.7
28.6
51.4
14.3
100.0
Cumulative
Percent (%)
5.7
34.3
85.7
100.0
75
4.3.1.16 Design for Simply Assembly
From Table 4.22 below, it indicates that 11.4% of the respondent respond that
Design For Simply Assembly respond it as “very important”, 54.3% respond it as
“important”, 25.7% respond it as “moderate”, 5.7% as “little important” and 2.9%
respond it as “not important”.
Table 4.22: Design for Simply Assembly
Not Important
Little Important
Moderate
Important
Very Important
Total
Frequency
Percent
1
2
9
19
4
35
2.9
5.7
25.7
54.3
11.4
100.0
Valid Percent
(%)
2.9
5.7
25.7
54.3
11.4
100.0
Cumulative
Percent (%)
2.9
8.6
34.3
88.6
100.0
4.3.1.17 Design to Avoid Return Visit by Trade
‘Design to Avoid Return Visit by Trade’ is also one of the concepts that should
be considered by designer in constructability in highway projects. More than half of the
respondent agreed that it is “important”, 8.6% respond it is “very important”, 31.4% it is
“moderate”, and 8.6% it is “little important”.
76
Table 4.23: Design to Avoid Return Visit by Trade
Little Important
Moderate
Important
Very Important
Total
Frequency
Percent
3
11
18
3
35
8.6
31.4
51.4
8.6
100.0
Valid
Percent (%)
8.6
31.4
51.4
8.6
100.0
Cumulative
Percent (%)
8.6
40.0
91.4
100.0
4.3.1.18 Design For Preassembly and/or Modularization
Referring to Table 4.24 below, it is seen that 5.7% of the respondent
‘Design For Preassembly and/or Modularization’ is “very important”, 37.1% respond it
is “important”, 48.6% it is “moderate”, 5.7% respond it is “little important” and 2.9% it
is “not important”.
Table 4.24: Design For Preassembly and/or Modularization
Not Important
Little Important
Moderate
Important
Very Important
Total
Frequency
Percent
1
2
17
13
2
35
2.9
5.7
48.6
37.1
5.7
100.0
Valid Percent
(%)
2.9
5.7
48.6
37.1
5.7
100.0
Cumulative
Percent (%)
2.9
8.6
57.1
94.3
100.0
77
4.3.2
Average Index Analysis for Degree of Importance of Constructability
Concepts in the Design Phase in Highway Projects
In analyzing the data using the average index, the following assumed values have
been used for the degree of importance of Constructability Concepts during the Design
Phase in Highway Projects; “Very Important”, “Important”, “Moderate”, “Little
Importance”, and “Not Important” and were coded as 5, 4, 3, 2 and 1 respectively. Table
4.25 shows the overall results for the Average Index Value for Degree of Importance of
Constructability Concepts during the Design Phase.
It can be seen that, the highest average index which is “Very Important” is 4.74
and the lowest value is 3.37 which is “moderate”. The highest 4.74 belongs to ‘Carry out
Thorough Investigation of The Site’ and the lowest is ‘Design For Preassembly and/or
Modularization’ with the index value 3.37.
The “Very Important” concept for the degree of importance of constructability
concepts in design phase in highway project that are the highest value 4.74 belongs to
‘Carry out Thorough Investigation of The Site’. This is followed by ‘Provide Detail and
Clear Design Information’ (4.57) and ‘Analyze Accessibility of the Jobsite’ (4.51).
The “Important” concepts are ‘Investigate the Impacts of Design on Safety
During Construction’ (4.34), ‘Consider Suitability of Designed Materials’ (4.29),
‘Investigate the Practical Sequence of Construction’ (4.26), ‘Consider Adverse Weather
Effect in Selecting Materials or Construction Methods’ (4.23), ‘Plan to Avoid Damage to
Work by Subsequent Operations’ (4.03), ‘Investigate Any Unsuspected Unrealistic or
Incompatible Tolerances’ (4.03), ‘Design for the Skills and Resources Available’ (3.97),
78
‘Consider Storage Requirement at the Jobsite’ (3.94), ‘Design for Minimum Time Below
Ground’ (3.83), ‘Design for Early Enclosure’(3.83), ‘Encourage Standardization/
Repetition’ (3.77), ‘Employ Any Visualization Tools to Avoid Physical Interference’
(3.74), ‘Design for Simply Assembly’ (3.66) and ‘Design to Avoid Return Visit by
Trade’ (3.60).
The only one concept that is moderate is ‘Design for Preassembly and/or
Modularization’ with the index value 3.37. From the results above, it can be conclude
that all the 18 constructability concepts that are studying are important, with the overall
average index which is 4.04.
79
Table 4.25: Average Index Value for Degree of Importance of Constructability Concepts during the Design Phase
Respondent’s Frequency
1.Carry Out Thorough Investigation of The Site
2.Provide Detail and Clear Design Information
3.Analyze Accessibility of the Jobsite
4.Investigate the Impacts of Design on Safety During Construction
5.Consider Suitability of Designed Materials
6.Investigate the Practical Sequence of Construction
7.Consider Adverse Weather Effect in Selecting Materials or Construction
Methods
8.Plan to Avoid Damage to Work by Subsequent Operations
9.Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
10.Design for the Skills and Resources Available
11.Consider Storage Requirement at the Jobsite
12.Design for Minimum Time Below Ground
13.Design for Early Enclosure
14.Encourage Standardization/Repetition
15.Employ Any Visualization Tools to Avoid Physical Interference
16.Design for Simply Assembly
17.Design to Avoid Return Visit by Trade
18.Design For Preassembly and/or Modularization
OVERALL AVERAGE INDEX
F
0
0
0
0
0
0
1
%
0.0
0.0
0.0
0.0
0.0
0.0
f
0
0
0
1
0
1
2
%
0.0
0.0
0.0
2.9
0.0
2.9
f
1
0
1
5
5
5
3
%
2.9
0.0
2.9
14.3
14.3
14.3
f
7
15
15
10
15
13
4
%
20.0
42.9
42.9
28.6
42.9
37.1
f
27
20
19
19
15
16
5
%
77.1
57.1
54.3
54.3
42.9
45.7
Total
f %
35 100.0
35 100.0
35 100.0
35 100.0
35 100.0
35 100.0
0
0.0
6
2.9
6
17.1
22 62.9
6
17.1 35 100.0
0
0
0
0
0
0
0
0
1
0
1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.9
0.0
2.9
0
0
2
0
0
0
4
2
2
3
2
0.0
0.0
5.7
0.0
0.0
0.0
11.4
5.7
5.7
8.6
5.7
9
9
9
8
14
10
7
10
9
11
17
25.7
25.7
25.7
22.9
40.0
28.6
20.0
28.6
25.7
31.4
48.6
16
16
12
21
13
21
17
18
19
18
13
45.7 10 28.6 35 100.0
45.7 10 28.6 35 100.0
34.3 12 34.3 35 100.0
60.0 6 17.1 35 100.0
37.1 8 22.9 35 100.0
60.0 4 11.4 35 100.0
48.6 7 20.0 35 100.0
51.4 5 14.3 35 100.0
54.3 4 11.4 35 100.0
51.4 3 8.6 35 100.0
37.1 2 5.7 35 100.0
*1=Not Important, 2=Little Important, 3= Moderate, 4=Important, 5=Very Important
Average Position
Index
4.74
1
4.57
2
4.51
3
4.34
4
4.29
5
4.26
6
4.23
7
4.03
4.03
3.97
3.94
3.83
3.83
3.77
3.74
3.66
3.60
3.37
4.04
8
9
10
11
12
13
14
15
16
17
18
80
5.00 4.74 4.57
4.51
4.34 4.29 4.26 4.23
4.50
Average Value
4.00
4.03 4.03 3.97 3.94
3.83 3.83 3.77 3.74
3.66 3.6
3.50
3.37
3.00
2.50
2.00
1.50
1.00
0.50
0.00
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 C17 C18
Constructability Concepts
Where
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
C12
C13
C14
C15
C16
C17
C18
Carry Out Thorough Investigation of The Site
Provide Detail and Clear Design Information
Analyze Accessibility of the Jobsite
Investigate the Impacts of Design on Safety During Construction
Consider Suitability of Designed Materials
Investigate the Practical Sequence of Construction
Consider Adverse Weather Effect in Selecting Materials or Construction Methods
Plan to Avoid Damage to Work by Subsequent Operations
Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
Design for the Skills and Resources Available
Consider Storage Requirement at the Jobsite
Design for Minimum Time Below Ground
Design for Early Enclosure
Encourage Standardization/Repetition
Employ Any Visualization Tools to Avoid Physical Interference
Design for Simply Assembly
Design to Avoid Return Visit by Trade
Design For Preassembly and/or Modularization
Figure 4.7: Degree of Importance of Constructability Concepts during the Design Phase
81
4.4
Level Of Application of Constructability Concepts
In this part, detail analysis using the SPSS program were use to clarify the
objectives. The researcher will use two types of analysis which are frequency analysis
and average index.
4.4.1
Frequency Analysis
Using the result from the questionnaire, the SPSS software is used to do the
frequency analysis of the level of application of constructability concepts in highway
projects.
4.4.1.1 Carry out Thorough Investigation of the Site
Referring to Table 4.26, it is seen that 65.7% of the respondents agreed that
‘Carry out Thorough Investigation of the Site’ is highly applied and the other 34.3% it is
in “medium application".
Table 4.26: Carry Out Thorough Investigation of the Site
Medium Application
High Application
Total
Frequency
Percent
12
23
35
34.3
65.7
100.0
Valid Percent
(%)
34.3
65.7
100.0
Cumulative
Percent (%)
34.3
100.0
82
4.4.1.2 Employ Any Visualization Tools to Avoid Physical Interference
Table 4.27 shows that 11.4% of the respondent agreed that this concept is highly
applied, 60% judged it of “medium application”, and 28.6% of “little application”.
Table 4.27: Employ Any Visualization Tools to Avoid Physical Interference
Little Application
Medium Application
High Application
Total
Frequency
Percent
10
21
4
35
28.6
60.0
11.4
100.0
Valid Percent
(%)
28.6
60.0
11.4
100.0
Cumulative
Percent (%)
28.6
88.6
100.0
4.4.1.3 Encourage Standardization/Repetition
For 31.4% of the respondents ‘Encourage Standardization/Repetition’ is high
applied, for 57.1% it is medium applied, 8.6% think is “little application” and the other
2.9% respond it “not applied at all”. Table 4.28 shows the percentage of this concept.
Table 4.28: Encourage Standardization/Repetition
Not Applied At All
Little Application
Medium Application
High Application
Total
Frequency
Percent
1
3
20
11
35
2.9
8.6
57.1
31.4
100.0
Valid Percent
(%)
2.9
8.6
57.1
31.4
100.0
Cumulative
Percent (%)
2.9
11.4
68.6
100.0
83
4.4.1.4 Consider Storage Requirement at the Jobsite
‘Consider Storage Requirement at the Jobsite’ is one of the constructability
concepts that have been applying in design phase in highway projects in Malaysia. Table
4.29 shows that 34.3% of the respondent said that it is highly applied, 57.1% said it is
“medium application” and 8.6% respond it as “little application”.
Table 4.29: Consider Storage Requirement at the Jobsite
Little Application
Medium Application
High Application
Total
Frequency
Percent
3
20
12
35
8.6
57.1
34.3
100.0
Valid Percent
(%)
8.6
57.1
34.3
100.0
Cumulative
Percent (%)
8.6
65.7
100.0
4.4.1.5 Design for Minimum Time below Ground
Refer to Table 4.30, it shows that 17.1% of the respondent replied that this
concept is “high application” in design phase in the highway projects in Malaysia. 62.9%
respond it is “medium application” and 20% of them respond it as “little application”.
Table 4.30: Design for Minimum Time below Ground
Little Application
Medium Application
High Application
Total
Frequency
Percent
7
22
6
35
20.0
62.9
17.1
100.0
Valid Percent
(%)
20.0
62.9
17.1
100.0
Cumulative
Percent (%)
20.0
82.9
100.0
84
4.4.1.6 Investigate the Practical Sequence of Construction
Refer to the Table 4.31, it shows that ‘Investigate the Practical Sequence of
Construction’ have been applying in the highway projects with 40% of the respondent
respond it as “high application”, 31.4% respond it as “medium application”, 25.7%
respond it as “little application” and 2.9% respond it as “not applied at all”.
Table 4.31: Investigate the Practical Sequence of Construction
Frequency
Percent
1
9
11
14
35
2.9
25.7
31.4
40.0
100.0
Not Applied At All
Little Application
Medium Application
High Application
Total
Valid Percent
(%)
2.9
25.7
31.4
40.0
100.0
Cumulative
Percent (%)
2.9
28.6
60.0
100.0
4.4.1.7 Design for Simply Assembly
For 37.1% of the respondent respond this concept is “highly applied”, 45.7%
respond it is “medium application”, 14.3 respond it is “little application” and 2.9%
respond it is “not applied at all”.
Table 4.32: Design for Simply Assembly
Not Applied At All
Little Application
Medium Application
High Application
Total
Frequency
Percent
1
5
16
13
35
2.9
14.3
45.7
37.1
100.0
Valid Percent
(%)
2.9
14.3
45.7
37.1
100.0
Cumulative
Percent (%)
2.9
17.1
62.9
100.0
85
4.4.1.8 Design for the Skills and Resources Available
Referring to Table 4.33, 37.1% of the respondent said it is highly applied, 57.1%
of the respondent found it as “medium application” and for 5.7% “little application”.
Table 4.33: Design for the Skills and Resources Available
Little Application
Medium Application
High Application
Total
Frequency
Percent
2
20
13
35
5.7
57.1
37.1
100.0
Valid Percent
(%)
5.7
57.1
37.1
100.0
Cumulative
Percent (%)
5.7
62.9
100.0
4.4.1.9 Investigate the Impacts of Design on Safety during Construction
‘Investigate the Impacts of Design on Safety during Construction’ is one of the
constructability concepts that have been applying in highway projects in Malaysia.
42.9% of the respondent agreed it is “high application”, 40% it is “medium application”
and the other 17.1% it is “little application”.
86
Table 4.34: Investigate the Impacts of Design on Safety during Construction
Little Application
Medium Application
High Application
Total
Frequency
Percent
6
14
15
35
17.1
40.0
42.9
100.0
Valid
Percent (%)
17.1
40.0
42.9
100.0
Cumulative
Percent (%)
17.1
57.1
100.0
4.4.1.10 Analyze Accessibility of the Jobsite
Referring to the Table 4.35, it can be seen that 42.9% of the respondent
considered this concept as “high application”, 40% as “medium application” and 17.1%
as “little application”.
Table 4.35: Analyze Accessibility of the Jobsite
Little Application
Medium Application
High Application
Total
Frequency
Percent
6
14
15
35
17.1
40.0
42.9
100.0
Valid Percent
(%)
17.1
40.0
42.9
100.0
Cumulative
Percent (%)
17.1
57.1
100.0
4.4.1.11 Design For Preassembly and/or Modularization
The level of application of ‘Design For Preassembly and/or Modularization’
concept, is high for 8.6% of the respondent, medium 68.6%, and little application for
22.9%.
87
Table 4.36: Design For Preassembly and/or Modularization
Little Application
Medium Application
High Application
Total
Frequency
Percent
8
24
3
35
22.9
68.6
8.6
100.0
Valid Percent
(%)
22.9
68.6
8.6
100.0
Cumulative
Percent (%)
22.9
91.4
100.0
4.4.1.12 Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
From Table 4.37 below, it can be seen that this concept’s level of application is
high for 20% of the respondent, medium for more than half of the respondent (57.1%)
and little for 22.9%.
Table 4.37: Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
Little Application
Medium Application
High Application
Total
Frequency
Percent
8
20
7
35
22.9
57.1
20.0
100.0
Valid Percent
(%)
22.9
57.1
20.0
100.0
Cumulative
Percent (%)
22.9
80.0
100.0
88
4.4.1.13 Design to Avoid Return Visit by Trade
Majority of the respondent (45.7%) classified ‘Design to Avoid Return Visit by
Trade’ in medium level of application, whereas 28.6% clarified it as “high application”,
22.9% as “little application”. This concept is “not applied at all” for 2.9% of the
respondent’s opinion.
Table 4.38: Design to Avoid Return Visit by Trade
Not Applied At All
Little Application
Medium Application
High Application
Total
Frequency
Percent
1
8
16
10
35
2.9
22.9
45.7
28.6
100.0
Valid
Percent (%)
2.9
22.9
45.7
28.6
100.0
Cumulative
Percent (%)
2.9
25.7
71.4
100.0
4.4.1.14 Design for Early Enclosure
The result from Table 4.39 below show that majority of the respondent (74.3%)
agreed that ‘Design for Early Enclosure’ is of medium level of application, 14.3%
respond it as “high application”, 8.6% “little application”, and 2.9% respond as “not
applied at all”.
Table 4.39: Design for Early Enclosure
Not Applied At All
Little Application
Medium Application
High Application
Total
Frequency
Percent
1
3
26
5
35
2.9
8.6
74.3
14.3
100.0
Valid Percent
(%)
2.9
8.6
74.3
14.3
100.0
Cumulative
Percent (%)
2.9
11.4
85.7
100.0
89
4.4.1.15 Provide Detail and Clear Design Information
57.9% of the respondents accepted that ‘Provide Detail and Clear Design
Information’ have been “medium application” in design phase constructability concepts
in highway projects in Malaysia. 37.1% respond it as high level of application, and 5.7%
as little level of application.
Table 4.40: Provide Detail and Clear Design Information
Little Application
Medium Application
High Application
Total
Frequency
Percent
2
20
13
35
5.7
57.1
37.1
100.0
Valid Percent
(%)
5.7
57.1
37.1
100.0
Cumulative
Percent (%)
5.7
62.9
100.0
4.4.1.16 Plan to Avoid Damage to Work by Subsequent Operations
From Table 4.41, the level of application of ‘Plan to Avoid Damage to Work by
Subsequent Operations’ is high for 40% of the respondents, medium for 40%, and little
for the other 20%.
Table 4.41: Plan to Avoid Damage to Work by Subsequent Operations
Little Application
Medium Application
High Application
Total
Frequency
Percent
7
14
14
35
20.0
40.0
40.0
100.0
Valid Percent
(%)
20.0
40.0
40.0
100.0
Cumulative
Percent (%)
20.0
60.0
100.0
90
4.4.1.17 Consider Suitability of Designed Materials
‘Consider Suitability of Designed Materials’ level of application is high for
54.3% of the respondents, medium for 40%, and little for 5.7%.
Table 4.42: Consider Suitability of Designed Materials
Frequency
Percent
2
14
19
35
5.7
40.0
54.3
100.0
Little Application
Medium Application
High Application
Total
Valid Percent
(%)
5.7
40.0
54.3
100.0
Cumulative
Percent (%)
5.7
45.7
100.0
4.4.1.18 Consider Adverse Weather Effect in Selecting Materials or
Construction Methods
31.4% of the respondent agreed that this concept application is “high
application”, followed by 48.6% of respond for “medium application”, 17.1% “little
application”, and 2.9% of respond for “not applied at all”.
Table 4.43: Consider Adverse Weather Effect in Selecting Materials or Construction
Methods
Not Applied At All
Little Application
Medium
Application
High Application
Total
2.9
17.1
Valid Percent
(%)
2.9
17.1
Cumulative
Percent (%)
2.9
20.0
17
48.6
48.6
68.6
11
35
31.4
100.0
31.4
100.0
100.0
Frequency
Percent
1
6
91
4.4.2 Average Index Analysis for Degree of Application of Constructability
Concepts in the Design Phase in Highway Projects
In analyzing the data using the average index, the following assumed values have
used. “High Application”, “Medium Application”, “Little Application” and “Not
Applied At All”, and were coded as 4, 3, 2 and 1 respectively. Table 4.44 shows the
overall results for the Average Index Value for Degree of Application of Constructability
Concepts during the Design Phase.
From the result that shown in Table 4.44, the highest average index for the 18
constructability concepts is 3.66 which is “high application” and the lowest value is 2.83
which is “medium application”. The highest value 3.66 belongs to ‘Carry out Thorough
Investigation of The Site’ and the lowest is ‘Consider Adverse Weather Effect in
Selecting Materials or Construction Methods’ with the index value 2.83.
The “high application” concept for the degree of importance of constructability
concepts in design phase in highway project is the highest value, 3.66, and belongs to
‘Carry out Thorough Investigation of The Site’.
The other concepts are “medium application”; ‘Employ Any Visualization Tools
to Avoid Physical Interference’ (3.37), ‘Encourage Standardization/Repetition’ (3.31),
‘Consider Storage Requirement at the Jobsite’ (3.26), ‘Design for Minimum Time Below
Ground’ (3.26), ‘Investigate the Practical Sequence of Construction’ (3.26), ‘Design for
Simply Assembly’ (3.20), ‘Design for the Skills and Resources Available’ (3.20),
‘Investigate the Impacts of Design on Safety During Construction’ (3.17), ‘Analyze
Accessibility of the Jobsite’ (3.17), ‘Design for Preassembly and/or Modularization’
(3.09), ‘Investigate Any Unsuspected Unrealistic or Incompatible Tolerances’ (3.09),
92
‘Design to Avoid Return Visit by Trade’ (3.00), ‘Design for Early Enclosure’ (3.00),
‘Provide Detail and Clear Design Information’ (2.97), ‘Plan to Avoid Damage to Work
by Subsequent Operations’ (2.97), ‘Consider Suitability of Designed Materials’ (2.86),
and ‘Consider Adverse Weather Effect in Selecting Materials or Construction Methods’
(2.83).
From the result above, it can be conclude that all the 18 constructability concepts
that are studying can be groups into two groups; medium and high application. Only one
concept is categorized “high application” and the others are “medium application”. The
overall concepts are medium in application for the design phase in highway projects, with
the overall average index of 3.15.
93
Table 4.44: Average Index Value for Degree of Application of Constructability Concepts during the Design Phase
Respondent’s Frequency
1.Carry Out Thorough Investigation of The Site
2.Employ Any Visualization Tools to Avoid Physical Interference
3.Encourage Standardization/Repetition
4.Consider Storage Requirement at the Jobsite
5.Design for Minimum Time Below Ground
6.Investigate the Practical Sequence of Construction
7.Design for Simply Assembly
8.Design for the Skills and Resources Available
9.Investigate the Impacts of Design on Safety During Construction
10.Analyze Accessibility of the Jobsite
11.Design For Preassembly and/or Modularization
12.Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
13.Design to Avoid Return Visit by Trade
14.Design for Early Enclosure
15.Provide Detail and Clear Design Information
16.Plan to Avoid Damage to Work by Subsequent Operations
17.Consider Suitability of Designed Materials
18.Consider Adverse Weather Effect in Selecting Materials or
Construction Methods
OVERALL AVERAGE INDEX
f
0
0
0
0
0
0
0
0
1
1
1
1
1
1
0
0
0
1
%
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.9
2.9
2.9
2.9
2.9
2.9
0.0
0.0
0.0
f
0
2
2
3
6
6
2
7
3
5
6
9
3
8
7
8
8
2
%
0.0
5.7
5.7
8.6
17.1
17.1
5.7
20.0
8.6
14.3
17.1
25.7
8.6
22.9
20.0
22.9
22.9
f
12
14
20
20
14
14
20
14
20
16
17
11
26
16
22
20
24
3
4
Total
Average Position
%
f
%
f %
Index
34.3 23 65.7 35 100.0
3.66
1
40.0 18 51.4 35 100.0
3.37
2
57.1 13 37.1 35 100.0
3.31
3
57.1 12 34.3 35 100.0
3.26
4
40.0 15 42.9 35 100.0
3.26
5
40.0 15 42.9 35 100.0
3.26
6
57.1 12 34.3 35 100.0
3.20
7
40.0 14 40.0 35 100.0
3.20
8
57.1 11 31.4 35 100.0
3.17
9
45.7 13 37.1 35 100.0
3.17
10
48.6 11 31.4 35 100.0
3.09
11
31.4 14 40.0 35 100.0
3.09
12
74.3 5 14.3 35 100.0
3.00
13
45.7 10 28.6 35 100.0
3.00
14
62.9 6 17.1 35 100.0
2.97
15
57.1 7 20.0 35 100.0
2.97
16
68.6 3 8.6 35 100.0
2.86
17
0
0.0
10 28.6
21
60.0
4
11.4 35 100.0
*1=Not Applied At All, 2=Little Application, 3= Medium Application, 4=High Application
2.83
18
3.15
94
4.0
3.66
3.37 3.31
3.26 3.26 3.26 3.20 3.20
3.17 3.17 3.09 3.09
3.5
Average Index
3.0
3.00 3.00 2.97 2.97
2.86 2.83
2.5
2.0
1.5
1.0
0.5
0.0
C1
C2
C3
C4
C5
C6
C7
C8
C9 C10 C11 C12 C13 C14 C15 C16 C17 C18
Constructability Conce pts
Where
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
C12
C13
C14
C15
C16
C17
C18
Carry Out Thorough Investigation of the Site
Employ Any Visualization Tools to Avoid Physical Interference
Encourage Standardization/Repetition
Consider Storage Requirement at the Jobsite
Design for Minimum Time below Ground
Investigate the Practical Sequence of Construction
Design for Simply Assembly
Design for the Skills and Resources Available
Investigate the Impacts of Design on Safety during Construction
Analyze Accessibility of the Jobsite
Design for Preassembly and/or Modularization
Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
Design to Avoid Return Visit by Trade
Design for Early Enclosure
Provide Detail and Clear Design Information
Plan to Avoid Damage to Work by Subsequent Operations
Consider Suitability of Designed Materials
Consider Adverse Weather Effect in Selecting Materials or Construction Methods
Figure 4.8: Degree of Application of Constructability Concepts during the Design Phase
95
4.5 The Development of Design Phase Constructability Improvement Concepts For
Malaysian Highway Projects
From the study, the guidelines of Design Phase Constructability Improvement
Concepts for Malaysian Highway Projects have developed by having the interview with
Encik Kamaruzzaman and Mr Lai Ming Siong, the highway engineers from Gemilang
Bina Sdn. Bhd. From the interview, they proposed the researcher to divide the guidelines
into two parts which is ‘very important’ and ‘important’ concepts. The ‘very important’
and ‘important’ concepts are the concepts that are important and must be taken into
consideration by the design engineers in design process, but the ‘very important’ should
be more attention to the designer.
The concepts developed represent current best practice in constructability that aim
at encouraging the project team to apply them, where appropriate, to their projects. By
the project team systematically addressing and expanding on all the issues presented in
each of the concepts a high level of constructability on a project can be achieved. The
titles of the concepts are given in Figure 4.9 below.
96
DESIGN PHASE CONSTRUCTABILITY IMPROVEMENT CONCEPTS FOR
MALAYSIAN HIGHWAY PROJECTS
VERY IMPORTANT CONCEPTS
1. Carry out Thorough Investigation of the Site
Constructability is improved when the information gathered from site investigation is
thorough and complete.
2. Provide Detail and Clear Design Information
Constructability is improved when thorough and clear presentation of design information
before the start of construction.
3. Analyze Accessibility of the Jobsite
Constructability is improved when the accessibility needs of manpower, material
and equipment are reflected in the detailed designs.
IMPORTANT CONCEPTS
1. Investigate the Impacts of Design on Safety during Construction
The design produced by the designers should enable the contractor to carry out their
works in a safe like manner.
2. Consider Suitability of Designed Materials
Products and materials to be specified during design should be selected with care,
particularly, any which have not long been established and accepted within the industry. It is
recommended that only products and materials, which have been proven suitable to be used,
are selected.
3. Investigate the Practical Sequence of Construction
The method of construction of project should encourage the most effective sequence of building
operations. Simple sequences enable each operation to be completed independently and without
interruption. The sequence should assist the coordination of trades and minimised delay.
4. Consider Adverse Weather Effect in Selecting Materials or Construction Methods
Project constructed in localities where weather conditions are adverse presents a great
challenge to both the designer and the constructor. Designers should investigate ways in
which the exposure to temperatures extreme and the effects of rain may be minimised.
97
5. Plan to Avoid Damage to Work by Subsequent Operations
The design should enable work to be carried out in a workman like manner without risk of
damage to adjacent finished elements and with minimum requirement for special protection.
6. Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
Constructability is improved when the design for building assembly observe the tolerances
which are normally achievable in site conditions, making allowances for the
differences between fine factory tolerances and those of normal site construction.
7. Design for the Skills and Resources Available
Constructability is improved when the technology of the design solution matched with the
skills and resources available.
8. Consider Storage Requirement at the Jobsite
Consideration should be given during the design stage to the location of material storage and
unloading facilities.
9. Design for Minimum Time Below Ground
Constructability is improved when the design minimize work below ground.
10. Design for Early Enclosure
Constructability is improved when the design enables early enclosure of the construction.
11. Encourage Standardization/Repetition
Constructability is improved when standardisation and repetition of design elements are
maximised.
12. Employ Any Visualization Tools to Avoid Physical Interference
Constructability is improved when visualisation tools are employed to visualise any
possibility of physical interference during construction.
13. Design for Simply Assembly
Constructability is improved when designs are simplified and configured to enable efficient
construction. Designers should produce the simplest possible details compatible with the
overall requirements for the building, particular element or group of elements.
14. Design to Avoid Return Visit by Trade
Constructability is improved when the design enable work to be carried out by a trade at one
work place and complete the work with as few return visit as possible.
15. Design For Preassembly and/or Modularization
Constructability is improved when pre-fabrication, pre-asseambly, or module designs are
considered early.
Figure 4.9: Design Phase Constructability Improvement Concepts For Malaysian Highway Projects
98
4.4
Summary of analysis and results
35 sets of questionnaires were used to obtain data from the respondents who
involved in highway projects in Kelantan, Terengganu and Johor Bharu. The
questionnaire survey was divided into 4 major sections. The first part consisted of
requests for relevant personal data of the respondent, such as the type of engineering
work performing, years of experience and etc. The second part consisted of 18 Likerttype five scale questions each presenting one constructability concept in design phase in
highway project and the third part was formulated to collect information regarding the
rate of application of each constructability concept in design phase in highway project in
Malaysia. The fourth part consisted of one question devoted to free response. All the
collected data from the questionnaires are analysed by two methods which are Frequency
and Average Index.
Part One represent the demographic section which the related to respondent’s
background as identify the type of organization, the level of study, the field of
specialization, the position in organization and to determine the numbers of years
practiced and working in highway projects. From the study, the researcher found that
most of the respondent comes from the contractor and consultant firm.
In Part Two, the respondents were asked to rate the degree of importance of the
constructability concepts during the design phase in highway projects. The results show
that for the eighteen concepts proposed, the total average index value is 4.04 which is
importance in design phase highway projects in Malaysia. The average index values of
the concepts also are consistent and it also can be seen same in the previous studies by
Nima (2002) and Rosli (2004). It shows that most of the respondents have knowledge
about constructability and its importance in achieving a good constructability.
99
In Part Three the respondents were asked to rate the degree of application of the
constructability concepts during the design phase in highway projects. The results of the
survey show that the respondents have categorized the concept as ‘medium application’.
That shows that the respondents have applied these concepts but not fully in their
projects.
CHAPTER 5
CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion
From the literature review and the result obtained the conclusion according to the
objectives of the study are as follows:
5.1.1 Objective 1: To identify the constructability concepts in highway projects.
From the literature review, eighteen important design phase constructability
concepts are applicable in highway projects. There were:
101
1. Carry out Thorough Investigation of the Site
•
Constructability is improved when the information gathered from site
investigation is thorough and complete.
2. Provide Detail and Clear Design Information
•
Constructability is improved when thorough and clear presentation of design
information before the start of construction.
3. Analyze Accessibility of the Jobsite
•
Constructability is improved when the accessibility needs of manpower, material
and equipment are reflected in the detailed designs.
4. Investigate the Impacts of Design on Safety during Construction
•
The design produced by the designers should enable the contractor to carry out
their works in a safe like manner.
5. Consider Suitability of Designed Materials
•
Products and materials to be specified during design should be selected with
care, particularly, any which have not long been established and accepted within
the industry. It is recommended that only products and materials, which have
been proven suitable to be used, are selected.
6. Investigate the Practical Sequence of Construction
•
The method of construction of project should encourage the most effective
sequence of project operations. Simple sequences enable each operation to be
completed independently and without interruption. The sequence should assist
the coordination of trades and minimised delay.
102
7. Consider Adverse Weather Effect in Selecting Materials or Construction Methods
•
Project constructed in localities where weather conditions are adverse presents a
great challenge to both the designer and the constructor. Designers should
investigate ways in which the exposure to temperatures extreme and the effects
of rain may be minimised.
8. Plan to Avoid Damage to Work by Subsequent Operations
•
The design should enable work to be carried out in a workman like manner
without risk of damage to adjacent finished elements and with minimum
requirement for special protection.
9. Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
•
Constructability is improved when the design for building assembly observe the
tolerances which are normally achievable in site conditions, making allowances
for the differences between fine factory tolerances and those of normal site
construction.
10. Design for the Skills and Resources Available
•
Constructability is improved when the technology of the design solution matched
with the skills and resources available.
11. Consider Storage Requirement at the Jobsite
•
Consideration should be given during the design stage to the location of material
storage and unloading facilities.
12. Design for Minimum Time below Ground
•
Constructability is improved when the design minimize work below ground.
13. Design for Early Enclosure
•
Constructability is improved when the design enables early enclosure of the
construction.
103
14. Encourage Standardization/Repetition
•
Constructability is improved when standardisation and repetition of design
elements are maximised.
15. Employ Any Visualization Tools to Avoid Physical Interference
•
Constructability is improved when visualisation tools are employed to visualise
any possibility of physical interference during construction.
16. Design for Simply Assembly
•
Constructability is improved when designs are simplified and configured to
enable efficient construction. Designers should produce the simplest possible
details compatible with the overall requirements for the highway, particular
element or group of elements.
17. Design to Avoid Return Visit by Trade
•
Constructability is improved when the design enable work to be carried out by a
trade at on work place and complete the work with as few return visit as possible.
18. Design for Preassembly and/or Modularization
•
Constructability is improved when pre-fabrication, pre-asseambly, or module
designs are considered early.
104
5.1.2 Objective 2: To identify the level of importance and application of
constructability concepts in design phase highway projects.
The respondents’ backgrounds were investigated in this research. From the total
numbers of 35 respondents, majority are working with consultant and contractor firms.
48.6% work in consultant firms whereas 31.4% work with contractor. Mostly all of the
respondents have B.Sc or Msc in Civil Engineering. They are civil engineers, designer
and quantity surveyor. Most of them have achieved 0-5 years of practiced in designing
and working in highway projects.
In Part Two, the respondents was asked to rate the degree of importance of the
constructability concepts during the design phase in highway projects. The result shows
that all of the eighteen concepts that have been proposed are ‘important’ in design phase
highway projects in Malaysia. This shows that most of the respondent have the
knowledge about constructability and know how importance is these concepts in
achieving a good constructability.
In Part Three the respondent were asked to rate the degree of application of the
constructability concepts during the design phase in highway projects. These concepts
have been categorized in ‘medium application’, which shows that the respondents have
applied these concepts but not fully in their projects.
105
5.1.3 Objective 3: To establish Design Phase Constructability Improvement
Concepts for Malaysian Highway Projects.
From the study, the concepts shown in Figure 4.9 are the Design Phase
Constructability Improvement Concepts developed for Malaysian Highway Projects.
The concepts developed represent current best practice in constructability that aimed at
encouraging the project team to apply them, where appropriate, to their projects as
shown in Figure 4.9.
5.2 Recommendations
There are a few recommendations in achieving a successful constructability in
design phase highway projects.
a. The constructability guidelines proposed in this study is only limited to highway
projects. It is recommended that similar guidelines should be developed for
other types of projects. Since the similarity in term of the most important
concepts of constructability that designers need to consider during the design
process are obvious, therefore more effort should be focused on identifying the
sub-factors under these most important concepts.
b. It was highlighted that project performance will improve, as the level of design
constructability gets higher. Since in this study there was no indication of the
actual impact on project performance it is recommended that work should be
carried out to determine the actual benefit gained from improved design
constructability in highway projects.
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APPENDIX A
Part One: Demographics
Please, thick one box and fill in the blanks if you select others.
Company Name: ……………………………………………………………………….
Address:
……………………………………………………………………….
……………………………………………………………………….
1. What is the type of your organization or company?
Owner
Contractor
Consultant
Others, please Specify………………..
2. What is the highest level of school you have completed?
B.Sc
M.Sc
Others, please Specify………………..
3. What is your field of specialization?
Civil Engineering
Mechanical Engineering
Electrical Engineering
Architect
Others, please Specify………………..
4. State your position in the organization?
Designer
Planner
Quantity Surveyor
Others, please Specify………………..
5. State the number of years you have practiced designing of highway projects?
0-5 Years
6-10 Years
11-15 Years
16-20 Years
More than 20 Years
6. State the number of years you practiced in working in highway projects?
0-5 Years
6-10 Years
11-15 Years
16-20 Years
More than 20 Years
Name:
Date:
Signature:
Part Two: Opinions
112
1 Carry Out Thorough Investigation of the Site
Constructability is improved when the information gathered from site investigation is thorough and
complete. Thorough site surveys (including determination of ground conditions, underground hazards
and other potential problems) are essential to avoid risk of delays and design changes during
construction.
2 Design for Minimum Time Below Ground
Constructability is improved when the design minimize work below ground. The application of this
concept is important especially when the ground is hazardous, poor or wet.
3 Design for Simply Assembly
Constructability is improved when designs are simplified and configured to enable efficient
construction. Designers should produce the simplest possible details compatible with the overall
requirements for the building, particular element or group of elements.
4 Encourage Standardization/Repetition
The standardization of components is based on recognition that savings can be realized when the
number of variations of components is kept minimum.
5 Design for Preassembly and/or Modularization
Preassembly is a process by which various materials, prefabricated components and/or equipment are
joined together at a remote location for subsequent installation as a unit. Preassembly often involves
decoupling sequential activities into parallel activities; and
A module is a product resulting from a series of remote assembly operations; it is usually the largest
transportable unit or component of a facility. Modules may contain prefabricated components or
preassemblies and are usually constructed away from the job site.
6 Analyze Accessibility of the Jobsite
The effect of accessibility can sometimes be quite serious such as delay in progress, slowed
productivity and increased damaged to completed work.
7 Employ Any Visualization Tools to Avoid Physical Interference
Constructability is improved when visualization tools are employed to visualize any possibility of
physical interference during construction. Computer visualization allows investigations to iron out
difficulties that may occur before construction commences on site.
8 Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
Particular attention should be given to the problems of fit which occur at the interfaces between
different products, methods of construction, materials and method of manufacture, and suitable jointing
methods should be adopted.
9 Investigate the Practical Sequence of Construction
Constructability is improved when adequate consideration of practical sequence of construction is
given. The method of construction of project should encourage the most effective sequence of building
operations. Simple sequences enable each operation to be completed independently and without
interruption. The sequence should assist the coordination of trades and minimized delay.
10 Plan to Avoid Damage to Work by Subsequent Operations
Constructability is improved when the damage to work by subsequent operations is considered.
Not Important
Little Importance
Moderate
Important
Constructability Concepts During the Design Phase
Very important
In your opinion, what is the degree of importance of the following concepts?
(Tick one, please)
11 Consider Storage Requirement at the Jobsite
Constructability is improved when storage requirement is adequately considered. Consideration should
be given during the design stage to be location of material storage and unloading facilities.
12 Investigate the Impacts of Design on Safety During Construction
Constructability is improved when the impact of design on safety during construction is adequately
considered. The design produced by the designers should enable the contractor to carry out their works
in a safe like manner. The design should be arranged so as to facilitate safe working in works such as
foundation and earth works, when materials and components are being handled, and wherever
traversing for access is necessary.
13 Design to Avoid Return Visit by Trade
Constructability is improved when the design enable a trade or specialist to complete all its work at a
work place with as few return visit as possible.
14 Design for the Skills and Resources Available
Constructability is improved when the technology of the design solution matched with the skills and
resources available. Any design is only good as skills available to execute it, either off-site or on-site.
15 Consider suitability of Designed Materials
Constructability is improved when suitable and robust materials are used. Products and materials
should be selected with care, particularly, any which have not long been established and accepted
within the industry.
16 Provide detail and clear Design Information
Constructability is improved when thorough and clear presentation of design information before the
start of construction. Sufficient time and resources must be allowed for this in design budget.
17 Design for Early Enclosure
Constructability is improved when the design enables early enclosure of the constructed building.
18 Consider Adverse Weather Effect in Selecting Materials or Construction Methods
Constructability is improved when the effect of adverse weather is considered. Project constructed in
localities where weather conditions are adverse presents a great challenge to both the designer and the
constructor. Designers should investigate ways in which the exposure to temperatures extreme and the
effects of rain may be minimized.
Not Important
Little Importance
Moderate
Important
Constructability Concepts During the Design Phase
Very important
113
Part Three: Opinions
114
1 Carry Out Thorough Investigation of the Site
Constructability is improved when the information gathered from site investigation is thorough and
complete. Thorough site surveys (including determination of ground conditions, underground hazards
and other potential problems) are essential to avoid risk of delays and design changes during
construction.
2 Design for Minimum Time Below Ground
Constructability is improved when the design minimize work below ground. The application of this
concept is important especially when the ground is hazardous, poor or wet.
3 Design for Simply Assembly
Constructability is improved when designs are simplified and configured to enable efficient
construction. Designers should produce the simplest possible details compatible with the overall
requirements for the building, particular element or group of elements.
4 Encourage Standardization/Repetition
The standardization of components is based on recognition that savings can be realized when the
number of variations of components is kept minimum.
5 Design for Preassembly and/or Modularization
Preassembly is a process by which various materials, prefabricated components and/or equipment are
joined together at a remote location for subsequent installation as a unit. Preassembly often involves
decoupling sequential activities into parallel activities; and
A module is a product resulting from a series of remote assembly operations; it is usually the largest
transportable unit or component of a facility. Modules may contain prefabricated components or
preassemblies and are usually constructed away from the job site.
6 Analyze Accessibility of the Jobsite
The effect of accessibility can sometimes be quite serious such as delay in progress, slowed
productivity and increased damaged to completed work.
7 Employ Any Visualization Tools to Avoid Physical Interference
Constructability is improved when visualization tools are employed to visualize any possibility of
physical interference during construction. Computer visualization allows investigations to iron out
difficulties that may occur before construction commences on site.
8 Investigate Any Unsuspected Unrealistic or Incompatible Tolerances
Particular attention should be given to the problems of fit which occur at the interfaces between
different products, methods of construction, materials and method of manufacture, and suitable
jointing methods should be adopted.
9 Investigate the Practical Sequence of Construction
Constructability is improved when adequate consideration of practical sequence of construction is
given. The method of construction of project should encourage the most effective sequence of
building operations. Simple sequences enable each operation to be completed independently and
without interruption. The sequence should assist the coordination of trades and minimized delay.
Not Applied At All
Little Application
Medium Application
Constructability Concepts During the Design Phase
High Application
In your opinion, what is the degree of application of the following concepts?
(Tick one, please)
10 Plan to Avoid Damage to Work by Subsequent Operations
Constructability is improved when the damage to work by subsequent operations is considered.
11 Consider Storage Requirement at the Jobsite
Constructability is improved when storage requirement is adequately considered. Consideration
should be given during the design stage to be location of material storage and unloading facilities.
12 Investigate the Impacts of Design on Safety During Construction
Constructability is improved when the impact of design on safety during construction is adequately
considered. The design produced by the designers should enable the contractor to carry out their
works in a safe like manner. The design should be arranged so as to facilitate safe working in works
such as foundation and earth works, when materials and components are being handled, and wherever
traversing for access is necessary.
13 Design to Avoid Return Visit by Trade
Constructability is improved when the design enable a trade or specialist to complete all its work at a
work place with as few return visit as possible.
14 Design for the Skills and Resources Available
Constructability is improved when the technology of the design solution matched with the skills and
resources available. Any design is only good as skills available to execute it, either off-site or on-site.
15 Consider suitability of Designed Materials
Constructability is improved when suitable and robust materials are used. Products and materials
should be selected with care, particularly, any which have not long been established and accepted
within the industry.
16 Provide detail and clear Design Information
Constructability is improved when thorough and clear presentation of design information before the
start of construction. Sufficient time and resources must be allowed for this in design budget.
17 Design for Early Enclosure
Constructability is improved when the design enables early enclosure of the constructed building.
18 Consider Adverse Weather Effect in Selecting Materials or Construction Methods
Constructability is improved when the effect of adverse weather is considered. Project constructed in
localities where weather conditions are adverse presents a great challenge to both the designer and the
constructor. Designers should investigate ways in which the exposure to temperatures extreme and the
effects of rain may be minimized.
Not Applied At All
Little Application
Medium Application
Constructability Concepts During the Design Phase
High Application
115