Content uploaded by Farook Hamzeh
Author content
All content in this area was uploaded by Farook Hamzeh
Content may be subject to copyright.
Enabling Lean with IT 761
INFORMATION FLOW COMPARISON
BETWEEN TRADITIONAL AND BIM-BASED
PROJECTS IN THE DESIGN PHASE
Malak Al Hattab1 and Farook Hamzeh2
ABSTRACT
Project success is intimately coupled with collaborative interaction among the
stakeholders and integration of information from everyone throughout the project life
cycle. Building information modeling (BIM) helps translate the owner’s value
preposition into a successful project by enabling continuous information flow and
delivering a high value product. On traditional 2D CAD projects, the information
flow between the players and project stages is jumbled. However, on BIM based
projects, the interaction is more flexible and overlapped where information is
aggregated and shared transparently between the different users (owners, architects,
structural and MEP engineers, consultants, contractors, and subcontractors).
The purpose of this paper is to understand how BIM can improve project
information flow. This is accomplished by modeling interactions among participants
across the conceptual and schematic design stages as opposed to the traditional
process of having information silos with sub-optimal communication between various
project players. In this respect, two process models are created for traditional and
BIM information flow. After that, a comparison between the two models is carried
out to assess the potential design process improvements resulting from the use of
BIM.
The research contributes towards highlighting where failure in communication
occurs and the hurdles preventing stream-lined workflow.
KEY WORDS
Building Information Modeling (BIM), Information Flow, Conceptual Design,
Schematic Design, Process Model.
INTRODUCTION
Efficient design management is essential to enable designers to proficiently respond
to the competitive construction industry and the clients’ requirements. Proper
administration of the design phase is critical to ensure compliance with the standards,
effectively translate the clients’ value prepositions into successful projects, and
satisfy cost and time constraints. On the other hand, changes in the design phase or
late information sharing results in drastic delays and problems downstream in the
construction phase. The research described in this paper focuses on the design phase
1 PhD Student, Civil and Environmental Engineering Department, American University of Beirut,
Beirut Riad El-Solh 1107 2020, Lebanon, Mobile +961 70 931272, mja28@aub.edu.lb
2 Assistant Professor, Civil and Environmental Engineering Department, American University of
Beirut, Beirut Riad El-Solh 1107 2020, Lebanon, Phone +961 1 350000 Ext: 3616,
Farook.Hamzeh@aub.edu.lb
Malak Al Hattab and Farook Hamzeh
762 Proceedings IGLC-21, July 2013 | Fortaleza, Brazil
of construction projects, that when managed properly, has high positive impacts on
the project’s downstream by saving time and preventing rework and cost overruns.
The design phase requires specific inputs to generate the required outputs. In fact, it is
commonly perceived that the design process is solely concerned with the thought
process that transforms these inputs into outputs and neglects the key role of
information exchange, the ‘fuel of design’, between the different members of the
design teams (Baldwin et al., 1999). The majority of the information shared by the
design participants rarely ends up actually adding value to the project despite the
increased amount of information being available for use (Phelps, 2012).
CONCEPTUAL AND SCHEMATIC VS. DETAILED DESIGN MANAGEMENT
This paper aims at understanding and comparing the information flow processes on
traditional 2D CAD projects and BIM-based projects under traditional project
delivery to identify where failure in communication occurs and the hurdles preventing
stream-lined workflow. This research focuses on studying information flow in the
conceptual and schematic design phases instead of the detailed design phase, the
former two phases being very iterative in nature and muddled with much
backtracking accompanying the exchange of information between design teams
(Austin et al., 2001). Additionally, changes at these two stages are more frequent and
have a larger overall impact on design than those at the detailed design phase
(Baldwin et al., 1999). On the other hand, the detailed design phase is well structured
and has more controlled information flows than earlier design phases, the latter which
witness multiple design alternatives carried simultaneously (Tribelsky and Sacks,
2010). This requires proper understanding and planning of the conceptual and
schematic design information flow to better manage data sharing and value
generation.
TRADITIONAL 2D CAD VS. BIM INFORMATION FLOW
BIM can be used as a noun to mean a building information model, an n-dimensional
model which is a compilation of building information of interrelated objects. One
might confuse a BIM to a regular 3D model; the latter however does not contain any
smart information as it is just a 3D representation tool. Moreover, BIM can be used as
“Building Information Modeling” referring to the process of using the provided
model and building information to simulate and help perform real activities involved
in the project (Eastman, 2008). The strength of BIM, which many users have not yet
realized as they think of BIM as just a “tool or software” rather than a “process”, lies
in the collaboration that BIM allows and requires between the stakeholders
throughout the project’s life cycle (Azhar, 2011). The major contributor for the waste
of information on projects is ineffective information sharing and flow. On traditional
projects, the information flow between the players and project stages is jumbled.
However, on BIM based projects, the interaction is more flexible and overlapped
where information is aggregated and shared transparently between the different users.
BIM streams information sharing of proposed designs that enable different design
teams to more easily collaborate using a ‘live’ version of the building model instead
of working in silos and snapshots. This way users can assess the impact of changes
more realistically on the overall design and in real-time rather than experience late
obsolete data hand-offs, back flows, and rework.
Information flow comparison between
traditional and BIM-based projects in the design phase
Enabling Lean with IT 763
In the lean environment, it has become generally recognized that planning and
managing the design process can improve project efficiency and client satisfaction.
However, methods pertaining to the design management focused on the detailed
design phase (Austin et al., 1999). Furthermore, research on BIM information flow
and modeling the conceptual and schematic design stage is very limited, and models
do not explicitly incorporate design deliverables and participants in their scheduling
process. In this respect, this research effort aims at providing a comprehensive
information flow process modeling of the conceptual and schematic design stages of
both traditional 2D CAD and BIM-based projects. In addition, it provides a thorough
comparison of both models to highlight problems in the traditional 2D CAD design
processes and the benefits of BIM use making the design phase lean.
RESEARCH METHOD
This research aims at understanding and comparing the information flow in the
conceptual and schematic design phases of both traditional 2D CAD and BIM-based
projects under traditional project delivery (D-B-B contract type). The specific aims
identified in this study include: (1) understanding how information flows on
traditional 2D CAD and BIM-based projects in the conceptual and schematic design
phases, (2) comparing the captured information flow between traditional 2D CAD
and BIM-based projects to realize the benefits of BIM use on projects, (3) assessing
the potential design process improvements resulting from the use of BIM in the
conceptual and schematic design phases, and (4) highlighting where failure in
communication occurs and the hurdles preventing stream-lined workflow.
To achieve the above research targets, the following research methods were
followed: (1) reviewing previous research work on traditional 2D CAD design phases,
(2) interviewing design professionals about the information exchange and flow
between the design participants on BIM-based projects, and (3) compiling this
gathered data and modeling the flows in cross-functional (swim-lane) diagrams.
PREVIOUS RESEARCH WORK ON TRADITIONAL 2D CAD DESIGN PHASES
A thorough revision was conducted on previous research work that studied data flow
in the building design process, the generation of data flow diagrams (DFD), and the
utilization of design structure matrices (DSM) to plan and manage the design phase
(Baldwin et al., 1999). Other studies targeted design iterations that were identified by
DSM and modeled through discrete-event simulation (Wang et al., 2005). Moreover,
other research efforts focused on extensive measuring of information flow in the
detailed design phase that aimed at identifying rework and bottlenecks occurring on
traditional 2D CAD projects (Tribelsky and Sacks, 2010). This paper aggregates
some of the stated research work and comes out with a traditional 2D CAD design
phase process model. This model not only shows the sequence of information
exchange in the conceptual and schematic design phase, but also divides the
information flow between the cross-functional participants, and presents the data
deliverables generated by the cross-functional teams design processes in order to
highlight potential design iterations, rework, delays and idle time, and unnecessary
repetitive processes.
Malak Al Hattab and Farook Hamzeh
764 Proceedings IGLC-21, July 2013 | Fortaleza, Brazil
INTERVIEWS WITH DESIGN PROFESSIONALS TO GENERATE THE BIM-BASED AND
VALIDATE THE 2D CAD PROCESS MODELS
In order to model the flow of information in the BIM-based design phase, research
work on BIM collaboration and the roles of participants in the modeling process were
reviewed, after which a preliminary process model was generated. The authors then
consulted with design professionals in the BIM field for their feedback on the
preliminary process model and interviewed them to further develop it. The design
professionals have over 20 years of experience working at major architectural/
engineering firms in the Middle East and the US. These firms use BIM on medium
sized residential buildings, large complex structures such as stadiums and convention
centers, as well as universities, airports, hospitals, and governmental facilities.
Moreover, to validate the data in the process model of the traditional 2D CAD design
phase information flow, the design professionals were also asked to provide their
feedback on the process model. The comments targeted the roles of the cross-
functional teams, the data deliverables of each design stage, and the interaction and
information exchange between the teams.
MODELING THE PROCESS OF INFORMATION FLOW INTO SWIM-LANE DIAGRAMS
After compiling the data of previous research work on traditional 2D CAD design
phases, and interviewing and consulting with BIM design industry professionals, two
cross-functional (swim-lane) diagrams were created for both project types. The
choice of swim-lane diagrams is not to only help visualize how the information flows
on each project, but to clearly identify how this information is exchanged between the
different design players (architects/ designers, structural/ civil engineers, MEP
engineers), and to highlight the information deliverables that flow on projects. These
information deliverables are functional primitive tasks (FPT), which are the low level
deliverables of a design process such as generating plans and sections, and they
exclude higher level activities such as developing and coordinating design concepts.
The latter activities, in fact, precede the FPTs, and are presented as processes and
sub-processes that generate these FPTs. Each model will be discussed in more detail
in the subsequent sections of this research paper.
PROCESS MODELS AND EXPLANATION
TRADITIONAL (2D CAD) DESIGN PHASE PROCESS MODEL
The traditional (2D CAD) design phase information flow was modeled in cross-
functional (swim-lane) diagrams. As mentioned earlier, the choice of swim-lane
diagram is for the fact that it helps present three things simultaneously: (1)
information flow, (2) clear information exchange between the different participants,
and (3) data deliverables resulting from each design process. The swim-lane diagram
shown in figure 2 is divided horizontally into three lanes (architect/designer,
structural/civil engineer, and MEP engineer). Vertically, the diagram is divided into
four phases. The first phase is the conceptual design phase, followed by review and
iterations (rework) period when the conceptual design phase tentatively ends, and
once the review period and any rework has been performed and accepted by the
owner, the schematic design phase is triggered. In a similar fashion, it is followed by
Information flow comparison between
traditional and BIM-based projects in the design phase
Enabling Lean with IT 765
a review and iterations period once the schematic design phase tentatively ends. After
receiving the approval of the owner, the design teams can then proceed to the detailed
design phase which will not be modeled since it is more stream-lined and
straightforward. The architects start by developing the design concept and then
generate information deliverables like preliminary massing and orientations of the
project. These deliverables are collected as documents, and after the architect concept
design ends tentatively, they are then passed on to the structural/ civil engineers who
have been waiting to receive these documents and experience delays and idle time.
Similarly, the structural/ civil engineers proceed with developing their concept design
and generate information deliverables. Meanwhile, the MEP engineers after also
waiting to receive the data deliverables from the architects, start developing their
concept design as well. Only after the teams have finalized their preliminary concept
designs, silos of information documents can then shared in iterative feedback loops
between the different teams to perform the necessary adjustments. Traditionally, the
teams have to submit their information deliverables to the architects and owners for
their decision, which results in either the acceptance (with comments) or rejection of
the design concept documents. In the case of rejection, which normally comes late as
it waits for the complete design input, the structural/ civil, MEP engineers, and
architects have to perform adjustments and rework in the design process and go back
again through several iterative loops before the design finally gets accepted. Upon the
owner’s approval, a final concept design report is generated to proceed with the
schematic design phase. This phase proceeds in a similar manner as the concept
design and includes several iterative and feedback loops, idle time and delays, rework
and adjustments until the approvals of the architects and owners are received.
Figure 1: Components of the Process Models of the Traditional and BIM-based
Design Phases
BIM-BASED DESIGN PHASE PROCESS MODEL
The swim-lane diagram shown in figure 3 is divided horizontally like the traditional
2D CAD design phase information flow swim-lane diagram. However, vertically,
only the conceptual and schematic design phase are present as the information
coordination, sharing, and owners’ feedback happen during each of these phases and
do not have to wait till the design is complete.
The concept design phase starts by developing the architectural concept in the
BIM environment and generating deliverables that are incorporated into the building
information model. Unlike the traditional 2D CAD design phase, the structural/civil
Figure 2: Information Flow Process Model of the Design Phase on Traditional 2D CAD Projects
Information flow comparison between
traditional and BIM-based projects in the design phase
Enabling Lean with IT 767
and MEP engineers do not have to wait until the completion of the architectural
design concept to proceed. Instead, early and easy data sharing is possible before data
completion, thus the three cross-functional teams can develop their design concepts
simultaneously. These concepts are modeled in the BIM environment, and result in
individual comprehensive building information models that are integrated into one
central model. This central model and individual models allow two-way information
sharing between the different design participants in real-time as well as prompt
adjustments of the model information after integrating and coordinating all the data.
In addition, the owner can get on board during the design concept development to
provide his early feedback on the design criteria as the required deliverables can be
extracted from the building information models at any time. This avoids the late
“acceptance or rejection” decisions which result in massive time and cost consuming
rework and countless design iterations as it happens on projects not using BIM.
After the completion of the conceptual design phase, there is no need to start over
and generate new models to develop the schematic design process. Instead, the
previous individual building information models are further detailed in accordance to
the required level of development (LOD) of the schematic design phase. This in turn
saves time of starting over and wasting time. The schematic design process then
proceeds in the same logic of the previous design phase.
INFORMATION FLOW COMPARISON AND DISCUSSION
There is a broad spectrum of possible BIM uses and benefits on construction projects.
When BIM is realized as a process extending throughout the lifecycle of the project,
instead of just a tool, the benefits can be realized. Along with its powerful ability to
provide n-dimensional visualizations, scheduling and cost estimations, different
building analysis (structural, civil, energy, safety…) and others, the power of BIM lies
in its ability to make an integrated and collaborative approach to design and
construction possible. In lean terms, effective communication, collaboration, and
working towards a common goal are keen on generating value for the owner and
reduce, if not eliminate, waste from the processes involved in delivering the project.
To gain a better realization of these benefits and how BIM enables a lean design
phase, a comparison between the two information flow process models is conducted
and the results are discussed:
Timely Incomplete Design Information Sharing and Communication: In
traditional 2D CAD design, the different participants have to wait for each
other’s design completion; the data deliverables are piled in silos before they
can be exchanged between the design teams. In such case, data can become
obsolete, in other words, the data goes to waste. In contrast, in BIM-based
design, early and timely exchange of incomplete information between
participants IS enabled by sharing and integrating the building information
models of the teams at any point in time. This allows real-time design
adjustments and development. The information is then always up-to-date, and
the clear design intent visualization facilitates communication between players
and allows for continuous information flow instead of interrupted batch flow.
Idle Time: The swim-lane diagram of BIM-based design phases clearly shows
the reduction in delays as opposed to the traditional design phases. As
Malak Al Hattab and Farook Hamzeh
768 Proceedings IGLC-21, July 2013 | Fortaleza, Brazil
mentioned above, since data sharing can occur even before the design is
complete, there is little or no idle time for the different teams when waiting to
receive complete data information from each other. Idle time is a large source
of waste in design and is a critical factor to be eliminated to prevent delaying
the design generation phase requested by the owner. Through the use of BIM,
such idle times and unnecessary delays of waiting are minimized or eliminated.
Owner Involvement and Value Generation: BIM enables the involvement of
the owner/owner’s representative and have him on board throughout the
design progress by the ability to extract any design information when required
from the integrated or individual models. In this respect, the owner’s early
feedback is of high value as it eliminates the late decision on the design data
which, if rejected, results in rework, cost and time waste. Moreover, by
involving the owner continuously as the design progresses, his value
preposition will be properly translated throughout the project life cycle.
Iterative Loops and Rework: Iterative loops are a result of limited
communication and information sharing. When data is shared in batches in an
untimely fashion, it tends to go back and forth between the various design
players in several loops before the design deliverables can exit the loop upon
the acceptance of the architect and owner. When rejected, which is normal in
design processes, the design deliverables have to be reworked. Since the
deliverables are in 2D CAD, any adjustment of a certain concept or a drawing
perspective, has to be reflected in all other trades/disciplines and views.
However, by using BIM, this can be done automatically by modifying the
model once in one view and all the other views are automatically modified,
and the other involved players can be instantaneously notified of the required
adjustments on their behalf (Hardin, 2009). This benefits the project reducing
negative iterations and rework, thus saving time and preventing cost overruns.
Quality of Design: Designers can make use of BIM to explore alternative
concepts, conduct value engineering and optimize their designs. BIM enables
collaboration among the different participants and allows data input from
everyone which generates a complete picture of the owner’s design intent in
everyone’s mind. In this regard, the architects and engineers will work towards
a common design of higher quality instead of having segregated ideas and lost
quality achievement along the jumbled iterative traditional design phase.
Future work: simulation of information flow
The process models can be used as a source of data for other tools and applications to
manage the design phase of construction projects in terms of cost, time, and resources.
To quantitatively assess the effectiveness of design management and to measure
potential time and cost savings realized from the use of BIM on projects, the authors
will further develop simulation models. These models transform the static process
models into dynamic models where the user can immediately observe the changes
with time advancement and while interacting with the model (Baldwin et al., 1999).
For this purpose, the simulation models of both design phase types will be applied on
case studies to assess the potential design process improvements resulting from BIM
use.
Figure 3: Information Flow Process Model of the Design Phase in BIM-based Projects
Malak Al Hattab and Farook Hamzeh
770 Proceedings IGLC-21, July 2013 | Fortaleza, Brazil
CONCLUSION
Extensive research and industry practice recognize the essential need for proper
design process management. Before implementing lean principles and BIM to
improve the design phase, it is necessary to realize that the major source of
information waste is sub-optimal information sharing, and to thoroughly understand
the iterative nature of the conceptual and schematic design stages. It is also necessary
to highlight the drawbacks in the traditional design practice across the industry.
In this regard, two process models for the information flow in traditional 2D CAD
and BIM-based design phases are modeled in cross-functional (swim-lane) diagrams.
The two models are then explained and compared to realize the benefits of BIM use
and to highlight the obstacles preventing stream-lined information flow. The results
of the comparison show a high ability for transforming the traditional design phase
into a lean design process by the use of building information modeling.
Project success is getting increasingly reliant on the entire information channel
between the entities of its supply chain. By analyzing the interactions within the
participants and the respective information exchange, the required interventions and
desired changes can be implemented. Such changes can boost connectivity between
project players to give way to a free flow of information throughout the entire project
life span, which transforms its delivery into a lean and waste-free process.
REFERENCES
Austin, S., Baldwin, A.N., Li, B., Waskett, P. (1999). “Analytical Design Planning
Technique: A Model of the Detailed Building Design Process.” Design Studies,
20(3) 279-296
Austin, S., Steele, J., Macmilla S., Kirby, P., Spence R. (2001). “Mapping the
Conceptual Design Activity of Interdisciplinary Teams.” Elsevier, Design Studies,
22(3) 211-231
Azhar, S. (2011). “Building Information Modeling (BIM): Trends, Benefits, Risks,
and Challenges for the AEC Industry.” Leadersh. Manage. Eng., 241-252
Baldwin, A.N., Austin, S.A., Hassan, T.M., Thorpe, A. (1999). “Modelling
Information Flow during the Conceptual and Schematic Stages of Building
Design.” Construction Management and Economics, 17(2) 155-167.
Eastman, C., Teicholz, P., Sacks R., Liston, K. (2008). BIM Handbook: A Guide to
Building Information Modeling for Owners, Managers, Designers, Engineers, and
Contractors, John Wiley & Sons, Inc., New Jersey.
Hardin, B. (2009). BIM and Construction Management: Proven Tools, Methods, and
Workflows, Wiley Publishing, Inc., Indianapolis, IN.
Phelps, A.F. (2012). Managing Information Flow on Complex Projects [Online].
Available: http://www.leanconstruction.org/chapterpdf/nor-cal/2012-03-14-lci-
nor-cal-meeting-phelps.pdf [Accessed 15 February 2013].
Tribelsky, E., Sacks, R. (2010). “Measuring Information Flow in the Detailed Design
of Construction Projects.” Res Eng Design, 21 189-206
Wang, W.C., Liu, J.J., Liao, T.S. (2006). “Modeling of Design Iterations through
Simulation.” Elsevier, Autom.Constr., 15 589-603
