Location Based Scheduling In The Form Of Flow Line And Its .

Location Based Scheduling In The Form Of Flow Line and Its Comparison to Cpm/Bar Chart SchedulingLSM has is the lack of critical path [6,11]. Thecritical path determines the smallest durationof the project, and determines which activitywill lengthen the project time if they aredelayed [6]. LOB is complicated especially forprojects which have large number of activitiesthat are related to each other or bounded tobe linked with time dependency. Such a timedependency like in highway projects primecoat should be followed by base course, whichis more related to dependency than productionor resource [5]. Plotting LOB must be carefullyevaluated, otherwise if too many activitiesare plotted in the schedule, the diagram willbe a jungle of tilted lines, and they may alsocross each other. Another major difficulty inplotting LOB is for the activities that havesame productivity and may overlapping eachother; it will not be easy to separate themunless they are drawn with different color.The scale of the lines should be appropriateso that it will be better understandable, andinformation can be readable easily [5,18].Mendes, Fernando & Heineck [14] and Lutz& Hijazi [7] described that the unpopularityof LOB in the construction industry wasmainly due to popularity of CPM commercialsoftware that made hard for LOB beat CPM inthe construction industry. Seppänen & Aalto[1] and Lutz & Hijazi [7] also stated aboutthe usage of LOB, despite of its strong toolbut it did not gain popularity in the worldwideconstruction industry mainly due to lack ofusing easy software to implement them.Between 1989 and 2003, Helsinki Universityin Finland started to develop the locationbased scheduling as an academic research.The new research improved scheduling skillsand used software to design a planning andcontrol tool. LBS is a combination of Linearscheduling and CPM, the schedule wasrepresented a graphical method called the894flow line, the same basic of line used in theLOB [21]. The concept of the planning is touse location breakdown instead of workingbreakdown structure, and the activities can beeither continuous work or discontinuous work[21].The objective of this study is to use LSB whichis a deviation of LOB with some modificationfor a small villa project, to see if it is anappropriate scheduling method to be used insmall, nonlinear, and non-repetitive projects.Methodology Of Lbs Wıth A Case StudyThis section presents the basic theory andmethod of planning and scheduling by LocationBased Scheduling, and its comparison toCPM/bar chart. To compare both methods, acase study of a 3 floor villa has been takenas an example. The case study of a 3 floorvilla has been planned and scheduled by bothmethods CPM/Bar chart and LBS.Planning Principle by LBSPlanning principle by LBS looks basicallylike the traditional CPM based planning. Thegeneral idea is: The plan must ensure that the projectobjectives can be achieved within thetime, resource and quality framework thatis applicable to the project.- The plan serves as a map of the projectshowing the intended path from start totarget.- The plan serves as a basis for analysis anddecisions choice of production methods,materials and equipment and otherresources.- The plan serves as a communicationinstrument that delivers production in racebuild up, what to do at each particulartime, what resources to be used, and inwhat order the work to be performed.

Alireza RezaeiAll these planning requirements are the sameregardless of the selected planning method,but the way to meeting the requirements aredifferent.Both LBS and CPM based have the same basicplanning elements and activities, resources andlinkages between activities. LBS also uses thetime analysis (network analysis) that the CPMmethodology uses it in the calculation of thecritical path and activities free and total slack.But these typical CPM concepts lose theirfunction in the LBS method, and instead, LBSintroduces concepts of locality critical latitudezone, location based activity bonds, resourceflow and other specific planning concepts.The fundamental difference between thetraditional CPM method and LBS is that theCPM method is based on the activities andtheir logical linkages to each other, while LBSmethod is increasingly based on resourcesand their “flow” through the project. TheCPM method activities are considered distinctelements which can be linked and analyzed ina logical network. The CPM method focuseson activities as categorized method as an“activity based planning method”.LBS as compared to the CPM is a “resourceoriented planning approach” where resourcesflow through the project is a key part ofplanning. An efficient flow means resourcesof the individual activities flowing smoothlyto the project’s various parts, or variousproject sites. Thus one geographical locationof the project activities, is achieved anidentification of where and when activitieswill take place, and it becomes possible torecord LBS method typical as a “time / placediagram”, or “flowline” diagram, which isLBS method graph. In flowline chart, thevertical axis location divided into projectphysical locations, and the horizontal axisindicates the project timing. The activities andtheir conduct described in this way as obliqueslopes, indicates the labor productivity ofactivities carried out, and the distance betweenactivity bars show the distance betweenactivities respectively the time and spacecalled “flexibility zones”.Case Study “A 3 Floor Steel Structure Villawith a Swimming Pool”A 3 floor steel structure villa in North Cyprusis taken as a case study (Figure 1).Figure 1: 3D CAD BIM model of a 3 floor steelstructure villa [22]The villa area is about 240 meter squarewith a swimming pool of 30 meter square,with structures consisting of both reinforcedconcrete and steel.This case study has been chosen due tofollowing reasons:1) The structure has been modeled and drawnby Revit, which is a 3D BIM modelingtool.2) The case study is real and has beenconstructed, and it was easy to find somemissing data, like rebar quantities, andstairs.3) It is a small building structure, which canINTERNATIONAL JOURNAL OF ELECTRONICS, MECHANICAL AND MECHATRONICS ENGINEERING Vol.5 Num.1 - 2015 (891-903)895

Location Based Scheduling In The Form Of Flow Line and Its Comparison to Cpm/Bar Chart Schedulingsatisfy one of the main objectives of thethesis.Identification of Location/Floors –Workspaces (The Project LocationStructure)Identification of project floors or workspacesis not a mandatory part of the traditionalCPM/Bar chart activity planning, but is a keyelement in LBS method. In LBS plan appearsproject hierarchical localities (e.g. building floor - zones - room), and each activity hasan efficiency in the schedule planned from alocation. Each location is connected to otherlocation in an order; each activity in a locationhas linkages between different activities.This implies a great difference in comparisonto the traditional CPM scheduling, whichexclusively handles the logical interconnectionlocational. Since the case study is 3 floor villawith a swimming pool, the structure of thebuilding is divided into four location floors,Basement, Ground Floor (G.F), First Floor(F.F), and Second Floor (S.F). Figure 2 showsa hierarchical locating quality structure thatis divided into floors of a 3 floor villa projectthat is taken from Revit 3D CAD and thenexported to Vico Office.physical parts and geographical areas, andthe work to be performed are divided intodifferent locations. The project floors areorganized in a hierarchy structure, calledthe Location Breakdown Structure (LBS).This hierarchical structure is same as WorkBreakdown Structure (WBS) that is used forthe structuring of the project in traditionalCPM/Bar charts or activity-based planning.Managing the Takeoff Item and QuantityUnit CostLBS defines the task as a group of activitieswithin a specific location, the activities aredriven LBS management tool, can easilyidentify the quantity of materials used in thebuilding by identifying them according totheir location, and where exactly this amountof material is used.After quantities have been taken off fromthe model, the LBS management tool has theability to plan the cost which is called costplanner. The tool consists of components,source quantity, markup value, unit cost, grosstotal, net total, add on, and others can be addedif required by the planner (Figure 3).Figure 3: Concrete component with subcomponent SPRW; Vico cost plannerFigure 2: Hierarchical location of 3 floor villa usingVico LBS manger software.After location is defined in the Vico office LBSmanagement, the Vico schedule planner willautomatically upload the locations in the flowline view of the vertical axis. The project’s896Managing Tasks for Schedule PlannerAfter components have been prepared in theLBS Management tool, the tasks should bedefined and derived in the manage tasks toolin cost planner. The tasks are the activitiesof the structure which will be scheduled andplanned according to their logic and location.After tasks have been defined, they can be

Alireza RezaeiFigure 4: Managing tasks with consumption rate; Vico task managereasily managed by dropping the componentsof the cost planner. For example after definingthe pouring of plain concrete activity in thetask manager, the quantity of this task wouldbe taken from the cost planner of quantitysource, then productivity will be defined forthat task to calculate the duration of task itwill take to accomplish the work (Figure 4).The duration of the tasks can be calculatedthrough the productivity of resource andtheir size by multiplying them to quantities.Equation 1 and equation 2 show how the crewhour and man hour are calculated [21].Manhours Quantity per location(unit) consumption rate(manhour)Crew hour ManhourEq.1Eq.2For example to find how much hour isneeded to finish “Tiling” work for the 3 floorsteel structure villa, with a quantity of 687meter square, the quantity is multiplied by aconsumption rate of 0.13 man hour/MS, tofind man hour then divided by the crew size,which one crew is used, the crew consist of 2tilers, 1 unskilled worker (UW), and one helper(HP). Consumption rates or productivity hasbeen assumed for the resources, some of themassumed by experience others were taken fromresearch done by Kazaz & Ulubeyli [23] inthe analysis of construction labors in Turkey.Locations with Dependency (LogicalRepresentation)LBS method uses dependency links orlinkages as CPM method. The logicalconstraint specifies the order of activities, orhow activities relate to each other. A logicalbinding specifies, for example, an activitymust start when another is completed. WithLBS method location based dependencydeveloped the use of the logical linkagesaccording to locations which activities areincluded. The four logical activity links alsoused in the CPM method which are: Finish Start (FS), Finish - Finish (FF), Start - Start(SS) and Start - Finish (SF). In the case study,FS logic activities are assigned to all tasks,because the succeeding task cannot start untilthe predecessor task finishes.LBS method uses all the traditional logicalactivity linkages, but adds additionalconstraints related to activities locations.INTERNATIONAL JOURNAL OF ELECTRONICS, MECHANICAL AND MECHATRONICS ENGINEERING Vol.5 Num.1 - 2015 (891-903)897

Location Based Scheduling In The Form Of Flow Line and Its Comparison to Cpm/Bar Chart SchedulingThere are five different types or levels oflocation based logic activities, which CPMdoes not support them. These layers interactwith CPM logic which forms a powerfullocation based logic or layered logic [24].In flow line view of scheduling, the verticalaxis represents the location, zones, or units,while the horizontal view represents theduration, which could be days, weeks, ormonths (Figure 5).Scheduling VisualizationSince the study objective is to perform acomparison between LBS and CPM/Barcharts, 4 types of scheduling have beenprepared. One of them is the traditionalCPM/Bar charts schedule and the other twoare Continuous LBS and DiscontinuousLBS. the discontinuous LBS schedule hasbeen transferred from traditional CPM/Barcharts into LBS without continuity force ofthe resources or crews, while the continuousLBS forces the crews to be continuous whileperforming their jobs, and it is also transferredto CPM/Bar charts.The flow line view can show morecharacteristics about the visual aspect, likesteeper slope line reflects to high productivity,while a flatter slope line reflects to a lowproductivity.LBS shows the scheduling visualizationthrough flow line concept, which is agraphical representation that shows the workand movement of resources through locations[21].The main objective of line of balance inlocation based scheduling is to schedule abalanced resource by using suitable crew sizeand number of resources [25].Production FlowConstruction projects typically consist ofrepetitive activities of the same resources invarious locations of the project. A work orproduction flow is defined in the LBS contextas activities and resources through movementof the project and its locations.LBS has the ability to schedule projects incontinuous flow, which forces the crew towork in a continuity way without interruption.Figure 5: Flow line View; Vico schedule planner898

Alireza RezaeiThe continuous production defines the work ofa task continuously from location to location[21].Defining Risk Levels and Monte CarloSimulationVico schedule planner has the ability to addrisk categories with their levels, and assessthem in Monte Carlo risk simulation whichcan mitigate the location based scheduling.There are five categories of risk that can beused in LBS:1) Starting risk: the risk or likelihood thattask will begin on time.2) Duration risk: risk or variability of aduration linked to individual location.3) Resource beginning risk: risk or variabilitytied to getting resource to mobilize whenneeded to begin in a task.4) Resource come back delay: delayassociated with a crew’s return if it forcedto demobilize.5) Production factor risk: risk or variabilityto production factor (i.e. skill level ofcrews).The risk levels were entered for every task,some tasks are more risky than others, somemay have no risk at all, which depends onthe contractor, subcontractor, or the crewsthemselves. The risks are entered according tologic of the work of crews, by experience ofthe planner, or by entering history agendas ofthe construction company. In this case study,the risk levels were entered theoretically andbased on practical experience. For examplethe risk entry level for excavation can bedifferent than the plain concrete. It can be seenthat the risk category of starting the project inexcavation is low, while for plain concreteis high. This is because of the experiencethat sometimes the mixer of concrete can bedelayed.After risks have been defined, a Monte Carlorisk simulation was done. The Monte Carlorisk simulation is a tool used to model andidentify the problem in the schedule. Theresults from the simulation can alert theplanner to make proactive decisions. Theprocess is like a throw dice or probabilitycalculation to access each of the different5 risk categories that has been defined inthe task of the 3 floor villa steel building. AMonte Carlo risk simulation was done to bothcontinuous flow and discontinuous flow, withthe same risk levels defined in both type ofproduction flow.Optimization of LBS TaskThe process of continuous flow of schedulingin LBS is different than the CPM. It extends theproject duration and consumes float. Buffersare used to absorb delay as mentioned before.The continuous flow produces time spacesbetween tasks as an example for the 3 floorsteel structure building. This time spaces canbe optimized by changing the flow line slopesand make them parallel to the predecessortasks, which will result in shortening theproject duration. The slope of the flow linecan be optimized by either changing the crewproductivity or adding resource number.This method of controlling flow line canalso be useful in the construction stage of theproject while the resources can be controlledaccording to their daily, weekly or monthlywork, unlike CPM it updates the scheduleduring the construction of the project.Results and DıscussıonsThe comparison is huge between the twoscheduling plans. The two scheduling plansCPM/Bar charts and LBS can be compared intwo categories; one as a general and anotherone as results. Table 1 shows the generalcomparison between CPM/Bar charts and LBS:INTERNATIONAL JOURNAL OF ELECTRONICS, MECHANICAL AND MECHATRONICS ENGINEERING Vol.5 Num.1 - 2015 (891-903)899

Location Based Scheduling In The Form Of Flow Line and Its Comparison to Cpm/Bar Chart SchedulingTable 1: General summaryGeneral characteristicsVisualization of the scheduleLocationTime representationBufferProduction rateRisk levelsCPM/Bar chartsOptimization of task in CPM/Barcharts can only be done by changingthe duration, or logics in CPM.OptimizationLBSFlow line view has a better visualBar charts are easy to read and mostespecially when it is colored, but itof the engineers can communicateis not suitable to use for so manywith it, but if so many activities arediscrete activities in differententered it will be hard to follow.locations.CPM/Bar charts use WBS, which isLBS uses location break downnot suitable for linear or repetitivestructure, which means it will beprocess.easier to show tasks within locations.WBS is represented in horizontal axis Locations can be represented eitheras duration.vertical or horizontal axis as a time.CPM uses float.LBS uses float and buffer.LBS uses the production rate toCPM/Bar charts can use theidentify the flow of resources,productivity to estimate duration butand the line is drawn according tothey do not depend on it.productivity rate.Uncertainty and risk probability isused on the resource time work andCPM uses PERT for durations.their production, rather than the timeitself.A case study has been used to collect the dataand results. One of the objectives is to seethat can LBS schedule a small 3 floor villa,and is it possible to make it continuous flow.Table 2 shows the results of CPM/Bar chartsdiscontinuous and continuous flow.As a summary from Table 2, the cost of theproject using both scheduling tools LBSOptimization can be done bychanging productivity of resourceswithout increasing risk.and CPM/Bar charts has a small differenceabout 726TL. For the duration of the project,CPM/Bar charts has more advantageous thanthe LBS method, this is because the criticalpath shortens the time, but at the same timethe project to finish on time is risky. Addingbuffer will decrease the risk and lengthensthe project duration, the buffer gives thecontinuous flow of LBS ability to optimize theflow lines, this will result into shortening timeTable 2: Results summaryResultsDuration with risk withoutbufferDuration with low risk andbufferCPM/Bar chartsStart 10/01/2013 End18/02/2014Start 10/1/2013LBS DiscontinuousStart 10/1/2013 End18/02/2014Start 10/1/2013End 28/03/2014End 28/03/2014900Start 10/01/2013 Finish19/05/2014Start10/01/2013Duration with low riskoptimizedTotal cost without bufferTotal cost with bufferTotal cost with optimizationLBS ContinuousStart 10/01/2013 End07/05/2014353,759 TL356,432TL353,759 85TL

Alireza Rezaeiof the whole project, so when risk and bufferare considered in the scheduling, the LBS hasmore advantageous feature of time shorteningthan the CPM/Bar charts .ConclusıonConstruction industry is growing widely;mega, linear, strategic and high rise buildingprojects are constructed. With these kindsof projects, construction companies seek aneffective, control and achievable planning andscheduling tool to plan their projects. Althoughthe popular used scheduling tools, like CPM/Bar charts are used widely in constructionindustry, whether it was big, medium, orsmall sized construction projects, but atthe same time most authors of constructionmanagement field criticized that CPM/Bar charts while used or applied on linear,repetitive projects. The linear scheduling toolsand their deviations like LOB, VPM, LBS, andothers give beneficial results in representingproductivity of resource, project progress,location correspondent and optimizationof the schedule. However, most of studiesof LSM or LOB focused on the linear andrepetitive projects ra

A modied method has been evolved which uses Location Based Scheduling (LBS) in the form of ow line scheduling, which is a combination of CPM and Linear Scheduling Method (LSM) which can be used for planning and scheduling of small, medium and big projects. This study uses the modied LBS method