Jihad Daniel paper of fast tracking design in megaproject construction


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Jihad Daniel paper of fast tracking design in megaproject construction

  1. 1. Fast-tracking Design in Megaproject Construction By Jihad DanielAbstract- Concurrent engineering is defined as the process of completing historicallysequential tasks in parallel. In this manner, concurrent engineering serves to reduceproject delivery times. The practice of overlapping activities is becoming a requirementfor fast-tracking complex construction projects. The nature of the information exchange,also known as the dependency, between pairs of activities determines the level to whichthe design and construction activities may be overlapped. This, in turn, determines thelevel to which various design disciplines may be overlapped. The first step in the processof quantifying the exchange of information is to formalize a methodology for studyingdependency among design activities. This paper addresses this issue through theexamination of a real world construction project – a multi-billion dollar educationalfacility in the Arabian Gulf. The study makes use of a common scheduling tool, theDesign Structure Matrix (DSM), to build the shortest schedule based on dependenciesamong the different design disciplines. Successful use of this approach can yieldsignificant time savings. This success is, however, contingent on: setting clear objectivesfrom the owner’s side, ensuring good communication between the consultant and thecontractor, and recognizing construction priorities and incorporating them into thedependencies. I. INTRODUCTIONGenerally, there are two main approaches for delivering a construction project, thetraditional approach and the fast-track approach. In the traditional approach, theconstruction phase of the project starts only after the design is fully complete.Conversely, in the fast-track approach, some amount of overlap takes place betweendesign and construction, leading to potential savings in the overall project execution time.The fast-track approach is usually defined under the umbrella of concurrent engineering,which is a work methodology based on performing tasks in parallel. Overlapping designand construction is an important aspect that characterizes the fast track delivery methodand has become more popular in the recent years.Scope of Work and Research ObjectivesThis study examines the relationships among the different design disciplines allowing for afast-tracked design phase and overlap design and construction. This study also uses theDSM (design structure matrix), a management tool, to determine optimal work schedules.After thoroughly defining those relationships, the attributes that govern the constructionstart lag and the overlap between design and construction are studied. The questions thatare addressed include: what design information is needed for each design package beforegoing into construction and how much design must be provided in a package to proceedwith the following one? What are the most significant packages upon which otherpackages depend on and without those packages the construction cannot proceed?This study also examines the level of involvement of the designer in the fast-track deliverymethod and the appropriate design methodology. The answers to these questions providea set of guidelines that help design companies create a compressed schedule. Concurrentengineering and the overlap approach in the fast-track delivery method approach arestudied thoroughly to help the design firms deliver projects with better time performance. Author: Jihad Daniel Page 1 of 12
  2. 2. II. BACKGROUNDFast-tracking is often described as overlapping successive activities to reduce project.Another definition of fast tracking is the compaction of the design and constructionschedule through overlapping of activities [1]. This usually involves starting constructionon a package before the completion of the whole project’s design. This improvement inproject delivery time does not necessarily come at the expense of quality and life-cyclecost [2]. Fast-tracking design and construction has been successful in reducing the projectschedule on multiple projects with little cost increase [3]. As to, the level to whichactivities may be overlapped, this depends on the type of the information transferbetween those activities and on the relationship between those activities whetherdependent (one way exchange of information), semi-dependent (one way exchange ofpartial information), independent (no exchange of information), or interdependent (twoway exchange of information) [4]. Another term that is used interchangeably with fasttracking is concurrent engineering. This is defined as “a systematic approach to theintegrated, concurrent design of products and their related processes, including,manufacturing and support”[5]. Concurrent engineering uses simultaneous, rather thansequential, processes. Most of the literature mentions the success of concurrentengineering in reducing project delivery times in the manufacturing industry. Severalstudies investigated the possibilities for concurrent engineering in the constructionindustry. Activities in the construction industry can be broken down into upstreamactivities such as project conception, specification, design, and downstream activities suchas construction, operation, maintenance, and decommissioning [6]. Jaafari studied fast-tracking in construction in terms of total life cycle management of capital projects. Hepresented a framework for implementing “concurrent construction”, an extension ofconcurrent engineering principles to the planning through commissioning of projects [7].Eldin presented four case studies of concurrent engineering in construction and concludedthat applying concurrent engineering standards could reduce the project schedule by up to25 percent in comparison with the schedule under the traditional delivery process.However, he also concluded that the construction industry was missing a definite modelfor applying overlapping design and construction in concurrent engineering [5].The literature proposed various methodologies which are the first step in a continuingstudy to create a formalized process for overlapping design and construction activitieswith the goal of reducing overall project delivery times.Much of the information studied in the literature was about the overlapping approach inthe context of the manufacturing industry. Few authors discussed this approach in thecontext of the construction industry. Yet, most of the information provided was about thebenefits of overlapping design and construction with no clear guidelines on how much tooverlap. Furthermore, the studies fall short of clearly determining the characteristics ofthe dependencies between the design and construction activities when they overlap. III. DESIGN STRUCTURE MATRIXThe DSM (design structure matrix) is a tool for modeling sequencing and is considered tobe a powerful and flexible tool for implementing the overlapping approach [8]. The mainadvantage of the matrix representation is that it is compact, and is able to provide asystematic representation of the tasks that is easy to read regardless of project size. Itclearly represents where interdependence occurs, and procedures to identify overlappingalternatives.The basic representation of the activity DSM is a square matrix containing a list ofactivities in the rows and columns [9]. Fig. 1 shows a basic DSM for six activities. Theclassification of activities in the rows or columns in the matrix specifies the sequence of Author: Jihad Daniel Page 2 of 12
  3. 3. execution. The information dependencies among the activities are represented with an Xmark in the assigned cells. The activities have are read along the columns as “givesinformation to” and along the rows as “needs information from.” [10]. Figure 1.Design Structure Matrix Representation [11]According to Maheswari et al., the marks above the diagonal are called feedback marksand the marks below the diagonal are called feed forward [11]. So, the more the marksabove the diagonal the more complex is the process. The DSM representation in the figureabove shows four marks (x) above that diagonal representing feedback information. Inorder to reduce these feedback marks (as thus reducing design process complexity) asimple sorting procedure is performed; that is, shuffling and rearranging rows andcolumns (i.e. activities) as a way to force all marks below the diagonal withoutaugmenting any of the existing relationships. IV. CASE STUDYThe purpose of the project is to provide educational services and accommodate for about40,000 fulltime graduate and undergraduate students and about 30,000 teaching staff andadministrative employees. The planned built up area of the project is about 2.8 million m2on a total site area of 800 ha. With the starting date in January 2009, the time limit fordesign and construction is only 2 years as the planned finishing date is January 2011.Meeting these time constraints was ensured by (Fig. 2): • Dividing the project into four smaller projects called “packages” • Allocating the packages to different contractors all working in parallel • Dividing the packages into smaller zones called “areas” each with certain functionality (e.g. Academic, Health Sciences, etc.) • Approaching the design for the areas on a facility by facility basis according to the client’s priority; • Designing each facility based on “design packages” that represent the different design disciplines and construction trades; • Issuing the design packages to the contractors according to their construction priority Author: Jihad Daniel Page 3 of 12
  4. 4. Figure 2.Project Breakdown Structure during the Design PhaseProject Subdivisions and Team AllocationAs mentioned earlier, the case study project is divided into four packages for constructioncontracting purposes. Each package is, in turn, divided into areas, and each area isdivided into facilities or buildings.The project is also divided into contractual zones. This division accomplishes severalgoals: • Help the consultant manage and control construction supervision; • Allow the contractors to approach construction according to the priority of each zone; • Facilitate site management and planning issues.One of the goals of dividing the project into areas is to facilitate design (Fig. 3). Author: Jihad Daniel Page 4 of 12
  5. 5. Figure 3.Packages versus Design AreasMilestonesThe case study is fast-track by nature. To meet the time constraint, the designer and thecontractors are planning to execute as much work in parallel as possible.The design team got the contractors on board during the schematic design-SD and designdevelopment-DD phases in order to help them fast-track their work. This wasaccomplished by starting common workshops and meetings. The design schedule was setwith both the client’s and the contractors’ needs in mind. The client set the projectpriorities in terms of which facilities should be ready to operate first. The contractors alsoprovided feedback on construction priorities.For example, the SBS and SPS design packages were not issued at the same time.Because of its importance to the launch of construction work, the SBS design package wasissued as soon as possible. To further reduce the risk of late delivery of key designinformation, an agreement was made between the consultant and contractors where thedrawings could be issued with a 60% in progress status in order for the contractor to startthe shop drawings and procurement activities.Design Dependencies and DeliverablesEach facility within the project consists of 6 design packages which are: the SBS, SPS,Architecture, Facades, MEP, and Finishes. These design packages cannot be start or finishat the same time due to the dependencies. Each design package needs information fromanother design package to be able to start the design with the exception of Architectureas the input of other disciplines to it occurs at a later stage. In this section, the concept ofdesign deliverables within each design package is discussed, and the exchange ofinformation is studied and quantified with the goal of quantifying the dependencies amongactivities. For this purpose, interviews with group leaders of all disciplines were done Author: Jihad Daniel Page 5 of 12
  6. 6. where each gave his or her vision of what and how much they deliver to the otherdisciplines by discussing: • The percentage of work done in each design package before it can be released to the other dependent design package; • The percentage or load of each deliverable within each design package.The methodology used to compute the percentages is as follows: • Previous experience of interviewed group leaders of the various engineering disciplines; • Amount of work done in a certain deliverable (e.g. the layout plan in Architecture is divided into walls, doors, windows, room tags, door tags, axes, dimensions, references…. Etc. So, the required amount of information needed to be delivered to MEP is only the walls, dimensions, doors, and windows and this constitutes about 60% of the work); • Total number of drawings submitted.The numbers were then anonymously validated and confirmed by four additional groupleaders from four engineering departments. As an example, Table 1 represents thepercentage and type of information delivered from Architecture to Façade, Sub Structures(SBS), Super Structures (SPS), Mechanical Electrical and Plumbing (MEP), and Finishes.As for the Architecture column it presents the load of work put into each deliverable. TABLE I INFORMATION EXCHANGE BETWEEN ARCHITECTURE AND OTHER DESIGN PACKAGESArchitecture Arch. Facade SBS SPS MEP FinishingAR1 Architecture layout plans, 70% 30% 50% 50% 30% 60% sections and elevationsAR2 Stairs details and circulation 20% X 80% 80% X 80% coresAR3 Fire zoning 10% X X X X 80% Total Percentage 100% 20% 50% 50% 20% 65%V. WHY AND HOW TO FAST-TRACK THE DESIGN OF A CONSTRUCTION PROJECT?Overlapping activities that are usually planned in a sequential manner can significantlyreduce project delivery times. However, overlapping design and construction comes withthe risk of costly rework. It is the duty of the project team to assess this risk of reworkagainst the time-saving by fast tracking project execution.To identify appropriate overlapping strategies, two main questions must be answered: 1- Why and when to overlap design and construction? 2- How to overlap project activities?By applying overlapping strategies in the right manner, project managers can make betterdecisions on when and how much to overlap sequential activities to reduce overall projectdelivery time. Author: Jihad Daniel Page 6 of 12
  7. 7. Why and When to Overlap Design and Construction?The main advantage of overlapping design and construction and overlapping differentdesign disciplines is to reduce the project time. This time saving is often correlated withan accelerated cash flow and faster recovery of investment.As such, the fast-track approach is often followed on large and complex projects whichhave a significant impact on the country’s economy or image, which is the case of theproject analyzed in this study. Having this large educational facility operational by early2011 is essential not only to the country’s economy but also to its image.This triggers other questions: What are the conditions that trigger or facilitate theoverlapping approach? And which activities can be overlapped?The analysis presented earlier indicates that all activities representing the differentengineering disciplines can be overlapped. So, one of the conditions that facilitates ormaximizes the benefits obtained from overlapping is the involvement of most or all of theengineering disciplines, taking into consideration the level of overlap that may varyaccording to the percentage and type of dependency that govern each pair of disciplines.Construction priorities play an important role in directing the overlap process amongactivities. For example, Façade is an activity that depends only on architecture with asmall percentage. Yet it is usually designed at a later stage since the SBS and SPS areconstructed first.Last but not least, dividing the project into several smaller projects and then allocatingeach sub project to an office also helps in overlapping the design process and moving thedesign of various facilities in parallel in order to fast track the project.How to overlap project activities?This section examines how consultants approach the design process with the objective ofminimizing the overall design duration. A process is developed to construct the shortestpossible design schedule, based on dependency data. This schedule is, then, comparedwith the planned schedule followed on the case study project.The first step is to summarize the information and dependency data using the DSM tool.The second step involves studying the dependency of each pair of design packages. At thislevel, consultants use their findings to identify what are the earliest possible and latestpossible time frame limits (or milestones) to release information to the dependentdisciplines or to construction.The last step in the process of building the shortest design schedule is to combine themilestones into one overall design schedule.The type of dependency can be presented in two ways, in the DSM and graphically asindicated in Fig. 4. Figure 4.Graphical Representation of Activity Dependencies Author: Jihad Daniel Page 7 of 12
  8. 8. The next step is to put all the gathered in formation in both representations in Fig. 5 and6 as follows: Figure 5.Graphical Representation of Activity Dependencies Arch. Facade SBS SPS MEP Finishing Arch. X X X Facade X SBS X X X SPS X X X MEP X X X Finishes X X Figure 6.Simplified Design Structure MatrixFig. 7 illustrates the new DSM acquired after rearranging some of the activities; the marksabove the diagonal indicate interdependent activities. Arch. Facade Finishes MEP SPS SBS Arch. X X X Facade X SBS X X SPS X X X MEP X X X Finishes X X X Figure 7.Final Simplified Design Structure MatrixFig.8 represents a part of a further expanded DSM including dependencies the differentdeliverables within each design package. The DSM was also expanded to include Author: Jihad Daniel Page 8 of 12
  9. 9. dependencies during all design phases. The numbers in the boxes represent thepercentages of the released or required information. Figure 8.Design Structure MatrixAlgorithmIn order to start (or proceed), each design package should receive the informationrequired from the dependent design packages. The assumption presented here is that inorder to meet the project tight schedule work on an activity starts as soon as someinformation is received from the other dependent activities. To make sure that the otherinformation is received while the activity is still ongoing, we built into the activity durationcomputation a condition ensuring that the duration is long enough to allow for allinformation to be received prior to releasing the deliverable. • There are k design packages • There are nk activities in design package k, where 1≤ k ≤ K • Duration of design package k is denoted as dk, where: ௡௞ dk ൌ ෍ dki ௝ୀଵ • dki is the duration of activity i in design package k • dvj is the duration of activity j in design package v, where design package v is the predecessor of design package k • Assuming a sequential design package flow, as represented in the streamlined DSM, then v = k-1, k-2,… 1 • pvjki = fraction of information required from activity j in design package v for activity i in design package k. Author: Jihad Daniel Page 9 of 12
  10. 10. • tvjki = earliest start time for activity i in design package k due to the required information from activity j in design package v. • tk = earliest start time for design package k. nk activities nk activities nk activitiesnk activities K=1 pvjki pvjkink activities pvjki K=2 pvjkink activities pvjki pvjki K=3 Example of a DSM Representation • Initialize: For k=1 implies v=0 • For v=1 to k-1 For j=1 to nv ; For i=1 to nk vj • Calculate t ki where: tv1k1 = pv1k1 x dv1 + tv and, tvj+1k1 = ∑݊‫ 1−ݒ‬dvj + pvj+1k1 x dvj+1 + tv ݆ൌ1 • Next (v) and Next (j): Sort tvjki from lower to higher, and then ¥ tvjki find: - Zvj = Min tvjki + dk If Zvj > Min tvjki , then stop and set tk = tvjki vj vj vj If not, then choose the next t ki to reach Z > Min t kiGaps between Optimal Schedule and Planned ScheduleFig. 10 shows a comparison between the optimal schedule derived from the DSM (red)and the planned schedule used on the project (blue). • The architecture design package has the same start and finish dates in both schedules due to the assumption that architecture always starts first at t=0; • There is a minimal difference in the schedules of SPS, MEP, and Finishes; • The planned schedule indicates that the SBS design package starts two months earlier than the optimal schedule. The reason for starting the design package earlier was because of the criticality of the SBS design package since it is the first activity in construction • Finally, the planned schedule indicates that the façade design package starts four months after the beginning of the architecture design package in the CD phase, whereas in the optimal schedule, Façade can start at 0.75 months. The reason behind not starting the façade design package earlier was again due to construction priorities.Author: Jihad Daniel Page 10 of 12
  11. 11. Figure 10. The Planned Schedule versus the Optimal Schedule VI. CONCLUSIONSSummaryTraditionally activities may be completed in a sequential manner. While, in the fast-tracksituation, activities are usually overlapped or worked in parallel in order to compress orreduce time. In order to fast-track large and complex projects it is important study themajor aspects such as project decomposition, team allocation, and dependencies.Breaking down the project into packages and smaller design packages can facilitate theprocess of overlapping and allows for the implementation of the fast-track approach. Thepackages are considered as smaller projects and can be allocated to different contractorsworking in parallel.The paper proposes a methodology for quantifying the amount of overlap between pairs ofdesign disciplines at a detailed level. The methodology describe the dependency in adetailed manner, taking into consideration the deliverables within each discipline, amountof information exchanged, and timing of exchange. Then the research suggested a formalprocess to translate the dependency information into a design schedule that representsthe earliest possible start date for each activity.The findings of this research mainly imply that overlap can be applied on various activitieswith a project to fast-track it.Therefore, timesaving can be significant when work is done in parallel, whether betweendesign and construction or between design activities.It is imperative to note that fast-tracking has several key requirements. First of all, clearobjectives set by the client and shared with the consultant and contractors are necessary.So is good communication between the consultant and the contractor; which isaccomplished by providing timely and clear information. It is important to have a capableconsultant with expertise in the fields of design and management, as well.Finally, construction priorities should be built into the dependencies; for example, priorityof constructing the SBS comes first. Author: Jihad Daniel Page 11 of 12
  12. 12. Future WorkFuture researchers can build a similar algorithm to study the dependency between designpackages and construction packages. The research can be also oriented to the cost orbenefit for overlapping by studying the quantifying of time saved versus the risk of reworkand the cost that may generate from compressing the schedule. In the project examined,the consultant was responsible for managing the interface between design andconstruction, also in coordinating the process and the communication between thecontractors.REFERENCES[1] G Pena-Mora F. and Park M. (2001), “Dynamic Planning for Fast-Tracking Building Construction Projects”.Journal of Construction Engineering & Management, 127(6), 445-456.[2] Smith, R. P. (1997). “The Historical Roots of Concurrent Engineering Fundamentals”. IEEE Transactions onEngineering Management, 44(1), 67-78.[3] Williams, G. V. (1995). "Fast Track Pros and Cons: Considerations for Industrual Projects”. ASCE Journal ofManagement in Engineering, 11(5), 24-32.[4] Yassine A., Chelst K., and Falkenburg D. (1999). “A Decision Analytic Framework for Evaluating ConcurrentEngineering”, IEEE Transactions on Engineering Management, 46(2), 144-157.[5] Eldin, N. N. (1997). "Concurrent Engineering: A Schedule Reduction Tool." ASCE Journal of ConstructionEngineering and Management, 123(3), 354-362.[6] De la Garza, J. M., Jr., P. A., Kapoor, M., and Ramesh, P. S. (1994). “Value of Concurrent Engineering forA/E/C Industry”. ASCE Journal of Management in Engineering, 10(3), 46-55.[7] Jaafari, A. (1997). “Concurrent Construction and Life Cycle Project Management”. ASCE Journal ofConstruction Engineering and Management, 123(4), 427-436.[8] Krishnan, V., Eppinger, S. D., and Whitney, D. E. (1997). “A Model- Based Framework to Overlap ProductDevelopment Activities”. Management Science, 43(4), 437-451.[9] Bogus S., Molenaar K., and Diekmann J. (2005), “Concurrent Engineering Approach to Reducing DesignDelivery Time”. Journal of Construction Engineering & Management, 131(11), 1179-1185.[10] Bogus S., Diekmann J., and Molenaar K. (2005), “Evaluating the Consequences of OverlappingDependent Activities”. Journal of Construction Engineering & Management, CRC paper number 7539.[11] Maheswari, J. U., Varghese, K., and Sridharan, T. (2006). “Application of dependency structure matrix foractivity sequencing in concurrent engineering projects”. Journal of Construction Engineering & Management,132(5), 482–490.Author: Jihad Daniel Page 12 of 12