Cpm

Construction Management with Network Planning Technology CPM and PERT

byDr Wang, ShouQingDepartment of BuildingNational University of Singapore

IntroductionOutline:Undergraduate Module: BU3114/BU3380Graduate Module: BS5235Lectures service as guideline only and emphasis will be placed on those require calculation and logic thinking/inference.Please read additional books/journals, do the tutorial questions (1a+b, 2 & 3) and finish the assignment given in the Outline.

Dr Wang, ShouQing, Department of Building, National University of Singapore

An Daily Life ExamplePlan 1: usual sequencePlan 2: change logic will affect total project time (TPT)Plan 3: change activity duration will affect the TPT tooSome activities determine the TPTA baseline for control established.Determine Finish from Start or vise versa

Importance of Planning/MgmtLessons learnt from the example:Working logic affects total project timeSome activities are critical while other are notA baseline for controlConstruction projects characteristics (unique, long period, outdoor, sequential & parallel activities, many parties/resources involved, lot of info) require well planningTo construct safely a quality facility on time and within budget with given resources


Key Decisions in Constr MgmtDefining What to DoDefining project scope based on contractPlanning How to DoOrganizing the project teamDeveloping the construction planSetting the cost budgetPlanning When to Do ItSequencing and scheduling activitiesAllocating people and resources to activities


Key Decisions (Cont)Executing the Work According to the PlanControllingMonitoring and recording project progress in terms of time and cost spent versus quantities of work in placeComparing actual with planned progressTaking corrective actions to eliminate unfavorable deviations or amending the plan to reflect the reality for subsequent controls


Philosophy of Management(similar to launching of a missile)The planning sets the targets to form the basis for controlling/management. The controlling ensures the project execute as planned or amended.


Project OrganizationPurposes of Project Organization: define flow of interactions among peopleWho decides whatWho tells whom whatWho respondsWho performs what workFunctions of Project OrganizationSpecialization (Horizontal division)Vertical Control (Down the levels of the hierarchy)Communication and Coordination


Structure of Project OrganizationBased on centralized, top-down decision making which can be represented by a hierarchy chart


Type of Project Task ForceProject team is headed by a PM but with different authority and relation between the task force and the headquartersArrangement depends on the project characteristics & companys policy and strategy on managementPure project type (PM has strong authority)Functional department type (PM as coordinator)Matrix type (intermediate form)


Pure Project TypePM has strong authority over his subordinate members.After project is completed, members are either sent to other sites or laid off.Adopted by most small-medium companies (also clients) to keep overhead cost low by deploying almost entire manpower on site and minimizing headquarters.


Functional Department TypeOpposite to the pure project type.Team members work together as expertise-contributors from various functional departments.PM acts merely as a coordinator.Position of departments is stronger than the PM.Common in design firm and some specialist contractors


Matrix TypeIn between pure project & functional department types.Decision-making shared by PM & functional depts.PM has authority over the team members while departmental managers have authority to instruct their staff assigned to the project.Found in large firms esp. design-build contractors.


Site LayoutFirst tasks to prepare a job layout for:Permanent facilities to be erectedAccess roadsOfficesWarehouses for tools and small materialsStorage of bulky materials & heavy equipmentYards for fabricating reinforcing steel & formsTower cranes


Site Layout (cont)Principles to follow:Enhance productivity: should minimize time consumed in moving heavy machines & bulky materials from storage areas to work placesMaintain safety: offices/warehouses to be near entrance to reduce chance of injuries to visitorsFacilitate communication: among participantsSecurity: to prevent theft & intrusionKeep work flows smooth: take into account constraints and requirements at different stages


Background Information Needed for Planning/SchedulingScope of work: e.g. quantity, qualityJob condition: e.g. site area, accessCalendar and holidays: e.g. work-day/weekWeather condition: e.g. raining, windyAvailability of resources (4Ms): e.g. constrain (limitation) per unit of timeProductivity: e.g. concrete in m3/man-hour


How/Where to Get InformationConstruction contractSite visitManagement strategies/policiesReasonable assumptions for unknownPast data/informationExperiences


Items to Be Adequately PlannedIdentification of activities of work requiredIdentification of inter-relationships of workThe optimum time to complete the projectThe time for delivery of materialsThe types, quantities, and duration of construction plantThe classification and numbers of workers needed and the periods they are neededThe amount and timing of finance required


Construction ActivitiesA construction project is broken down into specific activities (definable objective, scope, beginning and ending points)Work breakdown structure (WBS) is often usedOnce the activities are identified, the sequence of the activities (logic) should also be determined according to technical and managerial requirements


General Form of WBS


Fourth-Level WBSLevel 2Level 1Level 3Level 4


WBS Codes/NumbersTable of ContentsChapter 1 (level 1)Chapter 2 (level 1)Chapter 2.1 (level 2)Chapter 2.2 (level 2)Chapter 2.2.1 (level 3)Chapter 2.2.2 (level 3)Chapter 2.2.3 (level 3)Chapter 2.3 (level 2)Chapter 3 (level 1)Chapter 3.1 (level 2)Similar to the Chapter numbers of a book/ dissertation.Numbering depends on level.Useful for structuring project & arranging activities.Software can auto-assign WBS codes/numbers.


Activity DurationTo determine the length of time to accomplish an activity, the planner needs to:Take off the quantity of work for each activityDetermine the method of construction, crew types/ numbers and plant types/numbers to be usedEstimate the productivity of selected crew/plant performing the defined work based on job conditions and experiences etc.Usually, the more input of resources, the shorter the duration (Effort/Resource-driven Duration).


Activity Duration (cont)Formula: D = (P x Q)/(T x L) D: duration in days, P: productivity in man-hour/plant-hour per unit of work, Q: Quantity of work, T: hours per day, L: number of workers/plantsExample: Excavation of earth Given:Q = 500 m3, P = 0.8 man-hours/m3, L = 4 men,T = 8 hours/day Then:D = (0.8 x 500)/(8 x 4) = 13 daysThe duration of some activities such as curing of concrete depends on specifications.Sometimes it is hard to know the exact duration of some activities but its distribution.


Planning MethodBar chart (Gantt Chart)Popularised by Henry L Gantt and Frederick W Taylor in early 20 centuryShows works versus time (see next slide)Left part shows activities ID, name, duration, resources, cost, start/finish time, values etc.Right part, using time-related bars, shows each activitys start time, finish time and duration, etc.Principal advantage: readily understandableYet an extremely useful tool and may often be seen accompanying a network diagram


Example of Barchart


Total Project Time (TPT)Based on activities duration and logic, TPT can then be calculatede.g. The construction of 1 retaining wall consists of 9 sequential activities. TPT and each activities start/finish times could be determined using barchart as shown below (TPT=24days)IDActivityDurationPredecessorABCDEFGHI


Total Project Time (Cont 1)TPT vs. Resource Input: If there are 3 walls:Parallel: Shortest TPT (24d) while max. resource input (3 teams/sets)


Total Project Time (Cont 2)TPT vs. Resource Input: above 3 walls example, if:Sequential: Longest TPT (34d) while min. resource input (1 team/set)


Total Project Time (Cont 3)TPT vs. CostIn general, cost increases with longer/shorter TPTTPTTotal CostDirect CostIndirect CostOptimum TPTMin CostRequired Schedule vs. Balanced ScheduleCost


Chart1

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TimeDirect CostIndirect CostTotal Cost

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243741

362733

482028

5111425

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720727

827532

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10453.548.5

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Direct Cost

Indirect Cost

Total Cost

Planning Method (cont)Velocity Chart:Shows the relationship between time and output of a construction projectConstruction advance rate (production velocity) is indicated by the slope of lineSuitable for linear-in-nature projects but not for vertical project e.g. high-rise building


Velocity Diagram


Planning Method (cont)Line-of-Balance Chart:Derived from manufacturing industry and specialised tool for repetitive workRelating resources, activity duration, and the general pace of workDifficult to use on projects that require a large no. of trades or operationsGood for repetitive activities, e.g. tunnels, high-rise building


Line-of-Balance ExampleDiscontinuity of work allowed: e.g. after Remove form 1, stop 3 days, then Remove form 2. Pros: each activities finish at earliest time with shortest TPT=34dLayoutExcavateearthFixrebarPlaceconcreteCureconcreteRemoveformFinishingconcreteElectform3days3daysWall


Line-of-Balance Example (Cont)Discontinuity in work flows not allowed: e.g. Remove forms 1 to 3 continuously. Cons: longest TPT (=38d)LayoutExcavateearthFixrebarPlaceconcreteCureconcreteRemoveformFinishingconcreteElectformWall


Planning Method (cont)Network Technology (Diagram):Shows not only work-versus-time but also inter-relationship (logic) among work (activities)Developed in 1950s as an application to construction projectsGood analytical technique for planning, scheduling, controlling and co-ordinatingTheory: a branch of OR - graphical theoryTwo basic types: CPM and PERT


Modelling an Activity & ProjectProject Model established if each activity is modelled


Activity-on-Arrow Diagram with Determined Activity Duration4 days2 days1 days2 days3 days2 days1 days1 days1 days3 days


Advantage of Network TechnologyInter-relationship shown, know where & how an activity affects other activities and the projectA model for project established hence every activities time & other info can be calculated -> project plan can be optimisedCritical activities & critical path identified, hence know where to concentrate onResources allocation could be optimised (nCP->CP)With software, comprehensive tabular/graphic reports, e.g. Gantt Chart, S-Curve etc., are also available hence their advantages remain


Types of CPM DiagramsActivity-on-Arrow (Arrow Diagram)An activity is represented by one arrow & two nodesDummy activities are needed sometime to express correct logicActivity-on-Node (Precedence Diagram)An activity is represented by one nodeArrows depict logic onlyNo need for dummy activity (hence easier to draw & to apply computerActivity-on-Node is now more popular


Examples of DiagramActivity-on-Arrow Diagram (see previous slide)Activity-on-Node DiagramA node can be a circle, rectangle, etc.


Key Rules for Drawing Network DiagramDepict correctly inter-relationship (logic) among every activitiesFor a projects diagram, only one starting node and one ending node are allowed, i.e. no dangling node is allowedFor Activity-on-Arrow diagram, an activity should be represented by two unique nodes (ID), sometime dummy needed(Try to avoid bending/crossing of arrows & backward arrows to make diagram neat)


Logic Representation(A-O-A diagram)Tutorial


Logic Representation(A-O-N diagram)Tutorial


Example of Diagram Drawing


A site is divided into three areas. In each areas, four activities A, B, C, D are carried out in sequence, i.e. A->B->C->D, and from area 1->2->3, Draw network diagram.

1

A1,B1,C1,D1

2

A2,B2,C2,D2

3

A3,B3,C3,D3

Assume only one crew/plant for A, B, C and D respectively, e.g. one Excavator for A (excavation), Labor-1 for B (formwork), Labor-2 for C (steel bar), Labor-3 for D (concrete).

Activity-on-Node Diagram:

Technical Logic

Activity-on-Arrow Diagram:

Technical Logic

D1

C1

B1

A1

Arrange-ment Logic (Flow)

D2

C2

B2

A2

D3

C3

B3

A3

A1

D1

C1

B1

A2

Arrangement Logic (Flow)

D2

C2

B2

D3

C3

B3

A3

CPM Calculation: Why?Uncalculated network shows only logic, eg slideTo know time parameters of each activities and the project so as to produce planTo know more info about activities and project, e.g. critical/non-critical activitiesTo facilitate plan optimisation & adjustmentReduction of project time: e.g. where to reduce?Resource allocation: e.g. how many required daily?Resource levelling: to use resources evenly & avoid peak of demand for resources through TPTTime-cost trade-off: accepted time with min. cost


Calculation ProcedureBased on correctly drawn Network DiagramForward Pass Calculation (EST, EFT)Determine TPTBackward Pass Calculation (LFT, LST)Compute TFCompute FFIdentify Critical Path (CP)Above concepts will be explained in next example


Example: Calculation Directly on DiagramABDCEFGHI213322110TPT123456Timescale:11220334455ABECF66jiActivityDurationESTEFTTFLSTLFTFFLegend: Activity-on-Arrowk0StartFinishPlease follow the Train of ThoughtTerminology:Earliest Start Time: ESTEST1st activity=Project Start=0ESTjk= max{EFTij}Earliest Finish Time: EFTEFTij= ESTij + DijTotal Project Time: TPTTPT=max{EFTlast activity}=TcpLatest Finish Time: LFTLFTlast activity=TPTLFTij=min{LSTjk}Latest Start Time: LSTLSTij=LFTij - DijTotal Float: TFTFij=LSTij-ESTij=LFTij-EFTijFree Float: FFFFij=ESTjk-EFTijCharacters of TF & FFTFijFFijTFcritical activity=FFcritical activity=0

Example: Calculation Directly on DiagramTPTABDCEFGHI21332211012345611220334455ABECF66jiESTEFTTFLSTLFTFFk02222222222000000000002233333333315002555555555468888330Definition:Earliest Start Time: ESTEST1st Activity=Start Time=0ESTjk= max{EFTij}Earliest Finish Time: EFTEFTij= ESTij + DijTotal Project Time: TPTTPT=max{EFTlast Activity}=TcpLatest Finish Time: LFTLFTlast Activity=TPTLFTij=min{LSTjk}Latest Start Time: LSTLSTij=LFTij - DijTotal Float: TFTFij=LSTij-ESTij=LFTij-EFTijFree Float: FFFFij=ESTjk-EFTijCharacteristics of TF & FFTFijFFijTFcritical activity=FFcritical activity =0Follow the Train of ThoughtTimescaleActivityDurationLegend: A-O-AStartFinishCritical Path

Comparison of TF and FFTF: assume all activities start at EST; excess time (less duration) by which an activity can delay or expand without affecting TPT (but possibly affecting the EST of its succeeding activities)FF: assume all activities start at EST; excess time by which an activity can delay or expand without affecting the EST of its succeeding activities and the TPTFor an activity, always TF FF (? When =)


Comparison of TF & FFESTBAAESTALSTAEFTALFTATFABEFTBFFADADADBB is As immediate successorTFA=LSTA-ESTA=LFTA-EFTAFFA=ESTB-EFTA? TFB=? FFB=ABTFALSTBLFTB


Critical PathCritical Path (CP) is the chain of activities with zero TF; it is the longest duration path from Start Node to End Node in the networkTPT=Tcp=(Dactivities on CP)Increase/decrease of the Dactivities on CP affect TPT (?)Critical activities have zero TF and FFActivities on CP must be carefully monitored (?)There may be more than one CPs in a networkNon-CP may become CP if reduce Dactivities on CP? How to calculate Activity-on-Node Diagram?


AON Diagram CalculationSimilar to AOA, the only difference is:FFi = min{ESTj EFTi}Example: Calculation based on Calendar dates)StartEnd


Program Evaluation & Review Technology (PERT): BasicsSimilar in concepts and objectives with CPMDiffers in the time estimates: activities duration are with uncertainty, e.g. in new jobs which are subject to states of natureThis uncertainty is represented by probability distribution (beta distribution)


Uncertainty in Activity Duration - Beta Distribution


PERT Basics (cont)PERT utilises three time estimates:Optimistic or shortest duration possible (a)Most likely or normal duration (m)Pessimistic or longest duration possible (b)Duration distribution falls within a and b with m representing most likely, not (a+b)/2Assumptions:activities duration are independentTPT is with normal distribution


PERT ProcedureDraw network diagram (same as CPM)Calculate expected time for each activity:te=(a+4m+b)/6 (beta distribution theory)Calculate forward & backward & identify CPCalculate for activities on CP the Std Deviation = V =(b-a)/6 where Variance V=[(b-a)/6]2Calculate expected: TPT=(tcp)Calculate Std Deviation of TPT: SDTPT = cp2Estimate the probability of project completing by certain time and the level of confidence


PERT ExampleFind critical path (CP) and TPT using te values:pathABCD duration=3.33+3.0+5.33+8.33=20pathAEFD duration =3.33+3.0+6.83+8.33=21.49 (CP)pathAGD duration=3.33+3.0+8.33=14.66(or calculate the diagram using the same method of CPM)Find the Variance Vt and Standard Deviation of TPT:Vt=vt(AEFD)=0.444+0.111+0.25+1.0=1.805; =Vt=1.344te = 3.33vt =0.444A2 3 6te = 3.0 vt =0.444B1 3 5te = 5.33vt =1.778C2 5 10te = 8.33vt = 1.00D6 8 12te = 3.0vt =0.111E2 3 4te = 6.83 vt = 0.25F5 7 8te = 3.0vt =0.111G2 3 4te=(a+4m+b)/6vt=[(b-a)/6]2Activitya m bLegend:

PERT Example (cont)What is the probability of completing the project between 20 and 24 days?Za = (x-u)/ = (20-21.49)/1.344 = -1.11from the Normal Distribution Table:P(T

Relationship between Probability, Z & X


Usage of Calculation ResultsKnow more info about activities and the project (7 time parameters & CP)Various forms of plan (network, barchart, table, form, histogram, curve etc.) obtainable with auto-transfer/report functions of softwareConcentrate mgmt. on CP to ensure TPTDetermine the Effect of an activitys delay on its succeeding activities & the TPT (How?)


Usage of Calculation Results (cont)Adjust & optimise plan, e.g.:Pure TPT reduction & Time-cost Trade-off analysis: reduce Dactivities on CP (? Reduce which type of activities first & reduce which ones first?)Resource re-allocation: e.g. transfer from Non-CP to CP so as to help shorten TPT (? To what extent)Resource levelling: use resource evenly throughout project duration & avoid peak of demand (? What for)Without resource constrain: reschedule within TF (TPT)With resource constrain: reschedule may beyond TF (TPT)Costing & cashflow: get reasonable cashflow (?How)


Resource AllocationEarly vs. Late Schedules & Smooth


Smooth Resource Allocation


Resource Leveling Example(based on previous AON example)Earliest Schedule (ES/EF): TPT=46

Resource Histogram

Smoothness: Max=19, and #2 =8x142+10x192+2x172+=8181


Resource Leveling Example (Cont 1)Latest Schedule (LS/LF): TPT=46; Activities have no TF/FF (?why)

Resource Histogram

Smoothness: Max=19 and #2 =10x82+8x142+2x132+ =8053


Resource Leveling Example (Cont 2)Leveling: Reschedule D and E between ES and LS (why?), TPT=46

Resource Histogram

Smoothness: Max=14 and #2 =8x142+12x132+10x142+ =7453


Resource Leveling with ConstraintIf with resource constraint 12 men/day: TPT=72 (cf. ES/LS/Leveled)

Resource Histogram

Smoothness: Max=11 and #2 =8x62+30x82+10x112+ = ?


Resource Leveling with Constraint - Rescheduling Conflicting ActivitiesESTBAAESTALSTAEFTALFTABEFTBA & B are parallel activities requiring the same limited resource.LSTBLFTBIf A & B cant be carried out concurrently, there are two reschedule schemes:If reschedule B after A, the delay AB =?If reschedule A after B, the delay BA =?If more than 2 parallel activities, how many reschedule schemes?BAAB =EFTA LSTBBA=EFTB LSTABn!

Time-Cost Trade-off at ActivityTime for finishing a given activity varies with direct cost:Normal Point: the job is done with normal cost (min cost) in normal timeCrash Point: the job is done in crash time (min time) with crash costHow to Squeeze?Assign more men to workMore shift or work overtimeCrashPointNormalPointDrag out(abnormal)Min CostMin Time Pay premium to expedite material/equipment delivery Adopt alternative technology, e.g. fast but more expensive one Take risks on preliminary data to get a jump on design to gain timeCrash CostNormal Time


Time-Cost Trade-Off at ProjectTime-Cost Relationship at Project LevelMax cost with all activities being crashMin cost for normal durationMin duration (crash duration)Optimum Project DurationDuration for min cost (normal duration)Min cost for min durationOptimum DurationMin CostIndirect CostDirect CostTotal Cost


Chart1

35053

43741

62733

82028

111425

151025

20727

27532

35439

453.548.5

Direct Cost

Indirect Cost

Total Cost

Sheet1

TimeDirect CostIndirect CostTotal Cost

135053

243741

362733

482028

5111425

6151025

720727

827532

935439

10453.548.5

Sheet1

Direct Cost

Indirect Cost

Total Cost

Time-Cost Trade-Off ExampleDuration (day)121110987Indirect cost ($)900820740700660620Normal: Critical pathA, D, G Normal duration12 (how?) Direct cost610 Indirect cost900 Total cost1510AGBCDEF12


Time-Cost Trade-Off Example (Cont)Shorten Duration to 10 Days: Need to cut off 2 days Activity Normal Duration Crash Duration Cost Slope ($/day)A3250D5340G4270Solution: Shorten D from 5 to 3 days with added cost 2x40=80Normal direct cost610Added cost80Indirect cost740 (see last slide)Total cost1430? How to chose activities for shortening:Path: CP/non-CP which duration > target durationActivity: Along above paths, activities with less Cost SlopeOther rules: e.g. common activity of paths, longer duration?


Time-Cost Trade-Off Example (Cont)Shorten to 7 days: Check all paths in network diagramPath Normal dur Days to cut Additional cost A, D, G12 -5 1x50(A)+2x40(D)+2x70(G) = 270 B, G10 -3 1x60(B) = 60 A, F10 -3 2x30(F) = 60 C, E4 0 -Solution: Cut off 1, 2, 2, 1, 2 day from A, D, G, B, F respectivelyAdded cost270+60+60 = 390Normal direct cost610Indirect cost620 (see slide)Total cost1620? Selection of Schedule:According to management strategy etc.


Schedule Update & Performance ReviewRescheduling is the same as scheduling a new projectAdditional info required are % complete & actual dur. Actual duration = total duration* % complete Remaining duration = total duration*(1 % complete)Completed portion in a barchart is marked accordinglyThe Current Date (Review Date) is the basis for rescheduling. All unfinished activities will be scheduled forward from this date according to their duration/logicFor already finished, actual starts should be furnished to update the project schedule so as to make it consistent


Evaluating Project PerformanceThe starting point of project control. Original schedule & cost serve as baseline (target/budge), against which the actual performance in progress will be evaluatedBCWS: budget cost for work scheduled (the planned value of work so far)BCWP: budget cost for work performed (the earned value so far)Actual Cost: the real expenditure so farVariances of performance: negative is unfavorableSchedule Variance = BCWP BCWSCost Variance = BCWP Actual Cost


Graphic Representation of Performance


Evaluating Project PerformanceStatus of Project Completion: Alternative methodProject % complete=(Activity % complete*Activity % in project)Assume value of work is used to represent activity weight in projectProject % complete=(Activity % complete*Activity budge/Project budget) =(Activity % complete*Activity budget)/Project budgetThereforePlanned project % complete= (planned activity % complete*activity budget) project budgetActual project % complete = (actual activity % complete*activity budget) project budgetComparison can be made between the planned project % complete and the actual project % complete to evaluate project performanceBCWSBCWP


Project Performance Example

Evaluate Performance at end of day 15:BCWS=3840+19200*50%+ 4800*58%+4800*70% =19600 (see next slide)BCWP=3840+19200*60%+ 4800*20%+4800*60% =19200 (see next slide)Schedule Variance=19200 19600= 400 (see slide)Info is given. Current date is day 15. Only labor cost is considered. Activity cost is uniformly distributed over time.


Graphic Representation of the Example(Click on the picture to download the MS-Excel file)


Project Performance Example (cont)Actual Cost=3840/8*10+19200/30*12+4800/12*3+4800/10*6=16560Cost Variance = 19200 16560 = 2640Evaluate the Planned vs Actual Project % Complete:Planned project % complete = BCWS / Project budget =19600/46480 = 42%Actual project % complete = BCWP / Project budget =19200/46480 = 41%Schedule Variance in % =41% - 42%= -1% (slightly behind)(based on Schedule Variance, also = -400/46480-1%)Forecast of project cost at completion: $43200 (save 3280)Conclusions: the project is now on schedule & well under budget while the forecasts are also good.(see last slide)


Construction Planning with CPMAnalyse & breakdown project into activitiesFor each activity, determine:dependence/sequence (logic) with other activitiesestimate duration needed to complete this activityassign resources needed to carry out this activityDraw & calculate network, preferably by softwareIdentify CP, TPT, resource histogram, cost etc.Consider (physical, safety, resource, management etc.) constrains & make adjustments/optimisationImplement, monitor, control & adjust the plan


Why Use PM Software (PMS)The mathematical computations are instantaneous and error freeThe speed & accuracy of computations and analysis of information benefit greatly the project planning/scheduling and controlThe low cost and superb on-screen and hard copy graphics make it an effective communication and project control toolThe advantages of CPM are fully achieved only with use of PMS. Hence, No PMS, No CPM.


Major Functions of PMSNetwork processing (drawing & calculating the diagram based on calendar date)Resource allocation & levellingCost calculating/summarisingReporting & communicationSee hardcopy examples by Primavera Project Planner (P3) and MS-Project


The Advantages of P3 & Its Vendor: Primavera System, Inc.P3 is the best construction planning softwareP3 and its sister package, SureTrak, Primavera Systems, Inc., controls 75% market of the construction planning software in the USPrimavera Systems, Inc.s total market is construction management softwarePrimavera Systems, Inc. is among the top fifty computer software vendors in the US


The Advantages of MS-Project & Its Vendor: Microsoft Cor.MS-Project is for general planning purposeOperation of MS-Project is similar to MS-Office, hence very easy for MS-Office usersMS-Project is weak in Costing functionMS-Project is cheap and more obtainableMS-Project is suitable for beginnerMicrosoft Cor. is the dominant operation system and other software vendor in the world


MS-Project Software


Some Concepts in PMSSS, SF, FS or FF Lags (S-Start, F-Finish)

Effort-driven or Resource-driven DurationVarious Concepts of Time/Schedule: Calculated, Actual, Constrain, BaselineProject Calendar (the calculation based on)Resources Calendar (different resources may have different calendars)SF=6dFS= -1dSS, ie SASB=2dActivity A, 3dActivity B, 4dFF=3d


New Management Technique Lean ConstructionCritique of current practice, eg CPM/PERTRests on implicit transformation or activity theoryNo wrong but incomplete. It ignores work flow, uncertainty, and value creation & deliveryLC is a new way to manage construction production, with implications for commercial relationships & project delivery processes.Concept borrowed from M&P industry; started in construction in 80; still under developing.


New Management Technique Lean Construction (cont)LC planning & control techniques reduce waste by improving work flow reliability.The starting point is improving the reliability of assignments at the production level.Other features of LC:Combines flow & value, & max customer valueSimultaneous design & delivery process (D&B)Performance: instant delivery from 0 inventory-JITCoordinating logistics/crew through look-aheadPull: release resources only when system is ready


New Management Technique Lean Construction (cont)Current development of LCTheory & need have been well discussed (alternative name: Just-in-time (JIT), Total quality control (TQC), world class manufacturing, time based competition, re-engineering, etc)But lack of tools/software (research topic?).For more information on LC, visit web sites of:Lean Construction InstituteInternational Group for Lean ConstructionLean Enterprise Institute


Construction Planning/Management with CPM/PERTDr Wang ShouQing, Department of Building, National University of SingaporeConstruction Planning/Management with CPM/PERTDr Wang ShouQing, Department of Building, National University of Singapore

Cpm

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