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ABSTRACT Lean construction and BIM are two rapidly growing applied research areas in the realm of construction management. Both have justified their implementation by the significant improvements in the cost, schedule and quality of construction.
  INTEGRATION FRAMEWORK OF BIM WITHTHE LAST PLANNER SYSTEM TM Ankit Bhatla 1 , Fernanda Leite 2  ABSTRACT Lean construction and BIM are two rapidly growing applied research areas in therealm of construction management. Both have justified their implementation by thesignificant improvements in the cost, schedule and quality of construction. Leanconstruction aims to remove the wastes in the construction process while BIM aimsfor greater collaboration among the project teams during the design and constructionphases of a project. Both have been implemented independently on projects but thereis lack of research showing their applications together on construction projects. Usinga case of a major renovation project at the University of Texas at Austin, this paperpresents the benefits of BIM implementation and further focuses on developing anintegration framework of BIM with the Last Planner System TM of lean construction.BIM with its tools like 3D visualization, 4D simulation and MEP clash detectionleads to increased collaboration among the project team and when integrated with theLast Planner System TM , it can help in reducing the variability inherent in theconstruction process. This paper presents an integration framework of BIM at threelevels in the Last Planner System TM – at the Master Schedule level, LookaheadSchedule level and at the Weekly Work Plan level. The advantage of this integrationis also discussed in this paper. KEYWORDS Last Planner System, BIM, MEP Clash Detection, 3D Visualization, 4D Simulation INTRODUCTION The highly fragmented construction industry has been significantly affected by therapid development in lean construction and Building Information Modeling (BIM).More and more companies are taking to these two applied research areas to reap thebenefits from their implementation. While lean construction is a constructionmanagement philosophy focused on creating value for the customer (and eliminatingeverything that does not add value) using the least resources, BIM is focused more onapplication of information technology to increase collaboration among the projectparticipants in the entire project lifecycle. Construction labor productivity hasdeclined by about 20% between 1964 and 2003, while other non-farm industriesimproved by more than 200% (Teicholz, 2004). Research by the National Institute of Standards and Technology (NIST 2004) has further concluded that on averageinformation is recreated / reentered about 5-8 times in a project lifecycle and thisprocess discontinuity accounts for about 30% of the total process (about $15.8 billion 1 M.S., Department of Civil, Architectural and Environmental Engineering, University of Texas atAustin, 1 University Station C1752, Austin, TX 78712-0276,  2 Assistant Professor, Department of Civil, Architectural and Environmental Engineering, Universityof Texas at Austin, 1 University Station C1752, Austin, TX 78712-0276,   Bhatla and Leite Proceedings for the 20th Annual Conference of the International Group for Lean Construction  annually). Salmon (2009) reports that in the traditional design bid build projects over80% of the claims made are by the main participants like the owner, contractor andArchitects/Engineers (A/E) and 87% of the claims were based on Requests forInformation (RFI) and change orders. These examples are one of the many problemsbeing faced by the construction industry which can be remedied by lean constructionand BIM. Although lean construction and BIM are not dependent on one another (i.e.,lean construction practices can be adopted without BIM, and BIM can be adoptedwithout lean construction) Sacks et al. (2010) hypothesize that the full potential forimprovement of construction projects can only be achieved when their adoption isintegrated, as they are in the integrated project delivery (IPD) approach. A similarnotion is expressed in the American Institute of Architects document on IPD (Eckbladet al. 2007), “Although it is possible to achieve IPD without BIM, it is the opinionand recommendation of this study that BIM is essential to efficiently achieve thecollaboration required for IPD.” This paper delves into the combined application of lean and BIM on a project and discusses possible advantages of this implementation. LEAN PROJECT DELIVERY SYSTEM Ballard (2008, 2000b) defined the lean project delivery system as a model formanaging projects, in which project definition is represented as a process of aligningends, means and constraints. Alignment is achieved through a conversation with thecustomer stating what they want to accomplish (their goals and objectives) and theconstraints (location, cost, time) on the means for achieving their ends. The project isstructured and managed as a value generating process. Downstream stakeholders areinvolved in front end planning and design through cross functional teams. Projectcontrol has the job of execution as opposed to reliance on after-the-fact variancedetection. Optimization efforts are focused on making work flow reliable as opposedto improving productivity. Pull techniques are used to govern the flow of materialsand information through networks of cooperating specialists. Capacity and inventorybuffers are used to absorb variability. Feedback loops are incorporated at every level,dedicated to rapid system adjustment; i.e., learning. LAST PLANNER SYSTEM TM   "Last Planner" is the name for the LCI’s (Lean Construction Institute) system of production control. "Control" here means causing a desired future rather thanidentifying variances between plan and actual (Ballard (2000a), Ballard (2000b)).Production control consists of work flow control and production unit control. Work flow control is accomplished primarily through the lookahead process. Productionunit control is accomplished primarily through weekly work planning (WWP).Schedule planning for a project cannot be performed in detail much before theevents being planned. Consequently, deciding what and how much work is to be doneby a design squad or a construction crew is rarely a matter of simply following amaster schedule established at the beginning of the project. LPS TM is based on aShould-Can-Will-Do system of project planning. It focuses on making a 6-8 weekslookahead schedule with detailed weekly plans in discussion with the last planners(persons who actually execute the work) based on the current situations. Assignmentsare prepared for the workers to execute. In this way the workers are never overloaded,they only do what they promised and this helps to keep a track of the productivity.  Integration Framework of Bim with the Last Planner System Design Management  Failure to keep commitments is investigated so that they do not occur again. This isdone by a factor known as PPC (percent planned complete. As the Last PlannerSystem TM involves the pull approach to form a workable backlog, it utilizes the just intime tool, since all the project participants sit together to form the lookaheadschedule, wherein continuous improvement is built into the process. Thus the LastPlanner System TM serves to remove the uncertainties in the construction process. BIM Building Information Modeling, better known as ‘BIM’ has been defined in differentways by different authors. According to Sacks et al. (2010) BIM is “a verb oradjective phrase to describe tools, processes, and technologies that are facilitated bydigital machine-readable documentation about a building, its performance, itsplanning, its construction, and later its operation”. Smith (2007) has defined BIM as a“digital representation of the physical and functional characteristics of a facility. Itspurpose is to serve as a shared knowledge resource for information about a facilityand forming a reliable basis for decisions during its life-cycle from inceptiononward”. The concept of Building Information Modeling is to build a buildingvirtually, prior to building it physically, in order to work out problems, and simulateand analyze potential impacts. BIM is different from a 3D model is the sense that itexpresses the form, function, and behavior of objects (Tolman, 1999) .  Sacks et al. (2010) have provided detailed discussion on the most popular uses of BIM. Important uses relevant to this discussion are as follows:   1.   Visualization of Form (for Aesthetic and Functional Evaluation):   All BIMsystems enhance stakeholder participation by providing the ability to render thedesigns in 3D, making building designs more accessible to them.2.   Collaboration in Design and Construction: Collaboration in design andconstruction is expressed in two ways: “internally, “where multiple users within asingle organization or discipline edit the same model simultaneously, and“externally,” where multiple modelers simultaneously view merged or separatemultidiscipline models for design coordination. Whereas in the internal modeobjects can be locked to avoid inconsistencies when objects might be edited toproduce multiple versions, in the external mode only no editable representationsof the objects are shared, avoiding the problem but enforcing the need for eachdiscipline to modify its own objects separately before checking whether conflictsare resolved.3.   Rapid Generation and Evaluation of Construction Plan Alternatives : Numerouscommercial packages are available for four-dimensional (4D) visualization of construction schedules. Some automate the generation of construction tasks andmodeling of dependencies and prerequisites (such as completion of precedingtasks, space, information, and safety reviews and resources crews, materials,equipment, etc.) by using libraries of construction method recipes, so that changesto plans can be made and evaluated within hours.4.   Mechanical Electrical Plumbing (MEP) Clash detection:   MEP systems areextremely critical on technically challenging projects like hospitals,pharmaceutical industries. Deciding the routing and the spatial arrangement of the  Bhatla and Leite Proceedings for the 20th Annual Conference of the International Group for Lean Construction  MEP systems before construction execution hence plays an important role in thesuccessful execution of a project. A/E’s typically produce a schematic linediagram of the MEP system routing and the contractor relies on his specialty substo come up with the precise dimensions of the systems given the requiredspecifications by the A/E. Failure to identify the spatial dimensions of the MEPsystems and checking for potential clashes between the different MEP systemsbefore construction can result in a lot of rework which can further lead to timeand cost overrun (Khanzode, 2008). INTERACTION BETWEEN BIM AND LEAN Sacks et al. (2010) hypothesized positive interactions between many lean principlesand BIM functionalities. The lean principles that have the highest concentration of unique interactions are:a.   get quality right the first time and reduce product variabilityb.   focus on improving upstream flow variability, reduce production variabilityc.   reduced production cycle durations.The BIM functionalities that have the highest concentrations of unique interactionsare:a.   aesthetic and functional evaluationb.   multiuser viewing of merged or separate multidiscipline modelsc.   4D visualization of construction schedulesd.   online communication of product and process informationIn another research, Sacks et al. (2009)   while concentrating on fabrication, logisticsand installation of a building on site emphasize on the implementation on BIM andlean together to achieve stable flows and communicate pull flow signals. Theyhighlight that use of 4D CAD modeling can help to plan for stable work flow and tocommunicate standardized processes to workers. BIM models stored online onservers can be pulled up any time to look up detailed information on work packages.Due to increased collaboration between the project participants and increasedconfidence in the design, BIM implementation also aids in just in time delivery of materials and parts. BIM when combined with the Last Planner System TM can help infiltering work packages for maturity to ensure stability.Thus, from the above we can conclude that there are significant benefits of implementing BIM and lean in synergy with each other. Though Sacks et al. (2009)have emphasized on the integration of LPS TM with BIM, no framework has beenproposed suggesting what BIM functionalities are to be used and when are they to beused to increase value and flow reliability. This paper focuses on presenting anintegration framework of the LPS TM with BIM to provide for stable work flows andreduce the uncertainties inherent in the construction process.  Integration Framework of Bim with the Last Planner System Design Management  METHODOLOGY To prepare a framework for integration of the Last Planner System TM with BIM, itwas decided to select a project which used both the tools during the project execution.This was done to better understand the inherent practical issues in the application of both these tools simultaneously to find out synergy for the framework proposed inthis paper. The renovation of the Lee and Joe Jamail Swimming Center at theUniversity of Texas at Austin fitted the criteria thus established and was used toprepare the integration framework between the Last Planner System TM and BIM. HYPOTHESIS   TESTING The hypothesis being tested in the paper is that BIM and Lean are not independent of each other, maximum benefits can be realized by simultaneous implementation of both of BIM and Lean. Increased collaboration between project participants, reducednumber of RFIs and Change Orders leads to more value and greater satisfaction forthe customer. Due to lack of resources, the project participants did not use all aspectsof the Last Planner System TM and hence only the implementation of lookaheadschedule and weekly work plans during construction were analyzed for the purpose of this study. CASE   STUDY:   LEE   AND   JOE   JAMAIL   SWIMMING   CENTER,   UNIVERSITY   OF   TEXAS   AT   AUSTIN The Lee and Joe Jamail swimming center at the University of Texas at Austin wascompleted in 1977; however, due to the heavy wear and tear, it underwent a majorrenovation in the year 2010. The renovation project was handled by the ProjectManagement and Construction Services of the University. The contract required theuse of BIM, however, the level of use / deliverables were not mentioned. It was theowner’s first time experience with BIM whereas the contractor and the architect werefamiliar with BIM through past projects. The owner heavily relied on the experienceof the contractor for successful implementation of BIM. Owner’s initial expectationfrom BIM was only that of a 3D model which could clearly communicate the design.However, due to the contractor’s successful past experiences with BIM, the realm of BIM was increased to incorporate MEP clash detection. As it was a renovationproject, it was extremely important to accurately identify the existing utilities todevelop the routings of the new MEP system. This proved to be extremely difficultdue to the unavailability of ‘as-built drawings’. All the drawings had to be createdusing the 2D plans and site surveys. This was then combined into a 3D model inAutodesk REVIT by the Architect. The design process took a total of 13 months andwas followed by the construction phase. Before the start of the construction phase, theentire project team comprising of the owner’s project management team, contractorwith his team of subcontractors and the architect started weekly BIM coordinationmeetings. The objective of this meeting was to divide the project into different unitsand then identify clashes between the different utility systems like mechanical,electrical, plumbing, HVAC etc. to prevent late discovery of clashes that causerework. These coordination meetings were lead by the contractor who used 4 week lookahead planning followed by a weekly work plan to identify and resolve the
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