工程项目计划系统PPT课件

工程项目计划系统PROJECTPLANNING 在总目标确定后 分析总目标能否实现计划同时又是目标的分解过程计划是实施的指南和实施控制的依据业主和项目的其他方面需要利用计划的信息 一 计划的作用 Onedistinguishingfeatureofprojectsisthateachistailoredtowardsomeuniqueend itemorresult Thatuniquenessimpliesthateveryprojectmustbedefinedanewandaschemecreatedtellingeveryoneinvolvedwhattodo Threethingsoccurintheplanningandcontrolprocess 1 Duringtheconceptionanddefinitionphasesaplanispreparedspecifyingtheprojectrequirements worktasks responsibilities schedules andbudgets 2 duringtheexecutionphasetheplaniscomparedtoactualprojectperformance time andcost iftherearediscrepancies 3 correctiveactionsaretakenandtherequirements schedules andbudgetsupdated PlanningstepsForstarters theprojectteamneedstoanswerquestionsaboutwhathastobedone howithastobedone bywhom inwhatorder forhowmuch andbywhen Theformalizedwaytoanswerthesequestionsisthroughtheplanningprocess Projectobjectives requirements andscopeareset Thespecificworkactivities tasks orjobstoachieveobjectivesarebrokendown defined andlisted Aprojectorganizationiscreatedspecifyingthedepartments subcontractors andmanagersresponsibleforworkactivities Ascheduleispreparedshowingthetimingofworkactivities deadlines andmilestones Abudgetandresourceplanispreparedshowingtheamountandtimingofresourcesandexpendituresforworkactivitiesandrelateditems Aforecastispreparedfortime cost andperformanceprojectionsforthecompletionoftheproject ToolsofProjectPlanningWorkbreakdownstructureandworkpackages usedtodefinetheprojectworkandbreakitdownintospecifictasks Responsibilitymatrix usedtodefineprojectorganization keyindividuals andtheirresponsibilities Eventsandmilestones usedtoidentifycriticalpointsandmajoroccurrencesontheprojectschedule GanttCharts usedtodisplaytheprojectmasterscheduleanddetailedtaskschedules Networks clearlyshowinterdependenciesamongactivities Criticalpathanalysis criticalpathgivestheexpectedprojectduration PERT CPM programevaluation reviewtechnology criticalpathmethod Costestimating usedtodevelopbudgetsandbecomethebaselineagainstwhichprojectperformanceisevaluated Budgeting anestimatemayhavetoberefinedmanytimes butonceitisapproved itbecomesthebudget Forecasting planismadebeforeexecution soithasanatureofforecasting 二 计划的要求 目标是灵魂符合实际经济性要求全面性要求弹性要求详细程度要求相应的风险分析 三 工程计划系统1 计划过程 持续的 循环的 渐近的过程计划作为一个阶段 它位于项目批准之后 项目实施之前 而作为一个项目管理的职能工作 它贯穿于工程项目生命期的全过程 在项目过程中 计划有许多版本 随着项目的进展不断地细化 具体化 同时又不断地修改和调整 形成一个前后相继的体系 2 工程项目计划的内容工期计划成本 投资 计划资源计划质量计划其他计划 3 计划工作流程 总工期计划 项目定义 结构分解 组织结构设置 实施方案 劳动力使用计划 网络计划 资源使用计划 其他费用计划 成本计划 支付计划 收款计划 资金计划 符合实际 分解落实 否 是 4 计划中的协调 按照总目标 总任务和总体计划 起草招标文件 签订合同投标人的计划纳入整个项目的计划之中合同之间的协调不同层次计划的协调组织之间的协调 四 工期计划1 工期计划过程工期计划过程旨在确定工程活动的相关性及持续性 确保及时完成项目 它包括如下工作 安排并确定项目活动间的逻辑关系根据所需的资源 具体的条件 估计各项活动的持续时间 按总的进度目标编制详细的进度计划 形成网络 并进行网络分析 工期计划是其他计划的基础 2 计划总工期的确定和分解计划总工期作为项目的目标之一 对整个工期计划具有规定性 一般在目标设计阶段就被确定 并在可行性研究阶段被分解 细化 论证或修改 总工期目标和主要阶段的工期安排可以通过 分析过去同类或相似工程项目的实际工期资料 并根据本工程的特点推算 采用工期定额 行业标准的滞后性 企业定额 实际工程中 总工期目标通常从战略角度确定 3 工程活动持续时间的确定能量化的工程活动工程范围的确定及工程量的计算 劳动组合和资源投入量的确定 确定劳动效率 计算持续时间非定量化的工作按过去工程的经验或资料确定 与承担者协商确定持续时间不能确定的情况MonteCarlo模拟 Delphi专家评议 三种时间的估计法工程活动和持续时间均不确定滚动计划安排 加强对中间决策工作和决策点控制 横道图优点 清楚表达活动的开始时间 结束时间和持续时间 使用方便 可安排工期并与劳动力计划 资源计划和资金计划相结合 缺点 很难表达工程活动之间的逻辑关系 不能表示活动的重要性 所表达的信息量较少 不能用计算机处理 4 工期计划方法 GanttChartsThesimplestandmostcommonlyusedschedulingtechniqueistheGanttchart orbarchart namedafterthefamousmanagementconsultantHenryL Gantt 1861 1919 Thechartconsistsofahorizontalscaledividedintotimeunits days weeks ormonths andaverticalscaleshowingprojectworkelements tasks activities workpackages andsoforth DisadvantagesofGanttChartsOnedisadvantageoftheGanttchartisthatitdoesnotexplicitlyshowinterrelationshipsamongworkelements meaningthatitdoesnotrevealtheeffectofoneworkelementfallingbehindscheduleonotherelements Inmostprojects certainworkelementsmustbecompletedbyspecificdatetoensurethattheprojectiscompletedontarget however otherscanfallbehindwithoutdelayingtheproject 网络计划技术是一种以网状图形表示计划或工程开展顺序的工作流程图 分单代号和双代号两种 Thetwocommonmethodsforconstructingnetworkdiagramsarecalledactivity on node AON andactivity on arrow AOA Bothweredevelopedindependentlyduringthelate1950s AONaspartoftheCPMplanningmethod andAOAinthePERTmethod Activity on arrowdiagramsIntheAOAmethod theactivityisrepresentedasadirectedlinesegment calledanarroworarc betweentwonodes orcircles Thenodesrepresentthestartandfinisheventsfortheactivityinbetweenthem Thenumbersinsidethenodeshavenosignificancehere Ingeneral however theyareusedtoidentifyeachevent Thenumbersdonotneedtobeinanyparticularsequence buteveryeventmusthaveauniquenumber predecessor immediatepredecessor successor immediatesuccessor sequentialactivities parallelactivities dummyactivities AnAOAnetworkisconstructedbyfirstdrawinganodetorepresenttheoriginevent thisrepresentsthestartofthefirstactivityintheproject Thefinalorterminalnodeinthenetworkrepresentstheprojectcompletion Everynetworkshouldhaveonlyoneorigineventandoneterminalevent Allarrowsmustprogresstowardtheright endofthenetworkandtherecanbenodoublingbackorloops DummyactivitiesAdummyactivityisusedtoillustrateprecedencerelationshipsinAOAnetworks Itservesasa connector however andrepresentsneitherworknortime Inpractice dummyactivitiesshouldbeusedsparinglytokeepthenetworkassimpleaspossible Inconstructingnetworksbyhand asaruleitiseasiesttostartbyputtingindummyactivitieswherevertheyseemnecessary thenremovingthemfromplaceswheretheyarenotnecessary The overridingrule isthatdummiescannotberemovedwheneveritresultsintwoormoreactivitiesthatrunbetweenthesametwostartandfinishnodes RedundantactivitiesAllactivitiesinaprojectexceptthefirstonehavepredecessors Althoughonlytheimmediatepredecessorsneedbeknowntoconstructanetwork itiseasytoaccidentallyspecifymorepredecessorsthannecessary ThecriticalpathThemajoruseofnetworksisforscheduling determininghowlongtheprojectwilltake theexpectedprojectduration andwheneachactivityshouldbescheduled Theexpectedprojectduration Te isdeterminedbyfindingthelongestpaththroughthenetwork A path isanyroutecomprisedofoneormorearrows activities connectedinsequence Thelongestpathfromtheoriginnodetotheterminalnodeiscalledthecriticalpath thisgivestheexpectedprojectduration MultiplecriticalpathsCanaprojecthavemorethanonecriticalpath Whynot Inthecaseofmorethanonecriticalpath adelayalonganyofthesepathswouldextendtheprojectduration Suppose youwantedtoreducetheprojectduration youwouldthenhavetoshortenallthepaths Earlytimes ESandEFESsandEFsarecomputedbytakinga forwardpass throughthenetwork Whenanactivityhasseveralimmediatepredecessors itsESisthelatestEFofallitsimmediatepredecessors thisisthelatesttimewhenalltheimmediatepredecessorswillbecompletedand hence theearliesttimethenextactivitycanbestarted Latetimes LSandLFBeginbyassigningatargetcompletiondate TS totheterminalnode wemakea backwardpass throughthenetwork Wheneveranactivityisencounteredthathasmultiplepathsleadingbacktoit itisthelongestbackwardpaththatbecomesthebasisforitsLF ThisisthesameassayingthatitisthebackwardpathwiththesmallestLSthatprovidesthebasisforanactivity sLF TotalSlackTheESandLSforanactivityareoftennotthesame ThedifferencebetweenLSandES orLFandEF isreferredtoasthetotalslacktime orthe slack orthe float ofanactivity Totalslack LS ES LF EF Totalslackforactivitiesonthecriticalpath calledcriticalactivities iszero hence delayinganyoftheseactivitieswilldelaytheproject Activitiesnotonthecriticalpath callednon criticalactivities canbedelayedbytheirslacktimewithoutdelayingtheprojectcompletion FreeSlackThetermfreeslackreferstotheamountoftimeanactivitycanbedelayedwithoutaffectingthestarttimesofanysuccessoractivities ThefreeslackofanactivityisthedifferencebetweenEFfortheactivityandtheESofitsearliestsuccessor Freeslack ES earliestsuccessor EF ManagementschedulereserveTheTefirstcomputedfromthenetworkisusuallynotthedurationspecifiedasthecontractualcompletiontime AmanagementschedulereserveisestablishedbysettingtherequiredtargettimeTsatsomeamountgreaterthanthetimeofthefinalscheduledeventTe Generally thegreatertheuncertaintyoftheproject thelargertheschedulereserve CriticismofNetworkMethodsNetworkmethodshavebeencriticizedsincetheirinceptionbecausetheyincorporateassumptionsandyieldresultsthatsometimesareunrealisticorproseproblemstotheirusers Networkmethodsassumethataprojectcanbecompletelydefinedasasequenceofidentifiable independentactivitieswithknownprecedencerelationships Inmanyprojects however theworkcannotalwaysbeanticipated andnotallactivitiescanbeclearlydefined Rather projects evolve astheyprogress Also itisdifficulttodemarcateoneactivityfromthenext andthepointofseparationismoreorlessarbitrary Sometimessuccessorscanbestartedbeforepredecessorsarefinished sothetwo overlap inthesequence Althoughoverlapofactivitiesshortenstheestimatedprojectduration thearbitrarinessofdemarcatingtheactivitiesincreasesitsvariation Precedencerelationshipsarenotalwaysfixed however andthestartofoneactivitymaybecontingentupontheoutcomeofanearlieronewhichmayhavetoberepeated Theresultofatestactivity forexample maynecessitateredoinganalysisanddesign whichinanetworkisa loopback toactivitiesthatprecededthetest 网络计划的基本原理首先绘制工程施工网络图然后通过计算指出关键工作好关键线路接着选定目标不断改进计划 并对优化后的方案付诸实施最后在执行过程中进行有效的控制好监督 双代号网络图的绘制示例 2 A 3 B 4 C 5 D 6 E F G 8 H 1 7 关键工作和关键线路的确定若以网络终点节点的最早可能时间为网络总工期则关键线路上的各工作总时差皆为0若以合同工期为网络总工期 则以线路上总时差之和最小的线路为关键线路关键线路一般不止一条将关键线路的总时间缩短 关键线路可能变成非关键线路 各类时差的相互关系 Ti E Ti L Tj E Tj L PERTThreetimeestimatesPERTaddressuncertaintyinthedurationbyusingthreetimeestimates optimistic mostlikelyandpessimistic Theseestimatesthenareusedtocalculatethe expectedtime foranactivity Therangebetweentheestimatesprovidesameasureofvariability whichpermitsstatisticalinferencestobemadeaboutthelikelihoodofprojecteventshappeningatparticulartimes Theoptimistictimeisaminimumtimeactivitycouldtake thesituationwhereeverythinggoeswell themostlikelytimeisthenormaltimetocompletethejob thepessimistictimeisthemaximumtimeanactivitycouldtake thesituationwherebadluckisencounteredateverystep Thepessimistictimeincludeslikelyinternalproblemsbutnotenvironmentalsnags ThethreeestimatesarerelatedintheformofBetaprobabilitydistributionwithparametersaandbattheendpoints andmthemodal ormostfrequently value ThePERToriginatorschosetheBetadistributionbecauseitisunimodal hasfiniteendpoints andisnotnecessarilysymmetrical propertiesthatseemdesirableforadistributionofactivitytimes Basedonthisdistribution themeanorexpectedtimete andthevariance V ofeachactivityarecomputedusingthefollowingformulas te a 4m b 6V b a 6 2ThelargerV thelessreliablete andthehigherthelikelihoodthattheactivitywillbecompletedmuchearlierormuchlaterthante ProbabilityoffinishingbyatargetcompletiondateBecausestatisticallytheexpectedtimeofasequenceofindependentactivitiesisthesumoftheirindividualexpectedtimes theexpecteddurationoftheproject Te isthesumoftheexpectedactivitytimesalongthecriticalpath Te teWhereteareexpectedtimesoftheactivitiesonthecriticalpath Thevariationintheprojectdurationdistributioniscomputedasthesumofthevariancesoftheactivitydurationalongthecriticalpath Vp VWhereVarevariancesoftheactivitiesonthecriticalpath Asexamples considertwoquestionsabouttheprojectshownbelow 1 whatistheprobabilityofcompletingtheprojectin27days 2 whatislatestlikelydatebywhichtheprojectwillbecompleted Criticalpath Near criticalpath BothquestionscanbeansweredbydeterminingthenumberofstandarddeviationsthatseparateTsfromTe Theformulaforthecalculationis Near CriticalpathsPuttingtoomuchemphasisonthecriticalpathcanleadmanagerstoignoreotherpathsthatarenear criticalorhavelargevariances andwhichthemselvescouldeasilybecomecriticalandjeopardizetheproject Becauseallactivitiesinthenetworkmustbecompletedbeforetheprojectisfinished theprobabilityofcompletingtheprojectwithin29daysisthesameastheprobabilityofcompletingallfivepathswithin29days Thechanceofcompletingallpathswithin29daysistheproductoftheprobabilities 1 0 1 0 0 67 0 72 0 5 whichislessthan25percent SimulatingaPERTnetworkMonteCarlocomputersimulationisaprocedurethattakesintoaccounttheeffectsofnear criticalpathsbecomingcritical Timesforprojectactivitiesarerandomlyselectedfromprobabilitydistributionsandthecriticalpathiscomputedfromthesetimes Theprocedureisrepeatedthousandsoftimestogenerateadistributionofprojectduration TheproceduregivesanaverageprojectdurationandstandarddeviationthatismorerealisticthansimplePERTprobabilisticanalysis SimulationallowstheuseofavarietyofdistributionbesidesBeta includingdistributionsbaseduponhistoricaldata Thesegeneratedprojectdurationsaremorelikelytorepresenttherangeoftimetobeexpected ThemethodalsoavoidssomelimitationsofPERTassumptions suchasindependenceofactivitiesandnormalityoftheprojectdurationdistribution CriticismofPERTPERTassumesthatactivitytimescanbeaccuratelyestimatedandareindependent Gettingthreeestimatesinsteadofoneaddstotheworkinvolved andunlessthereisgoodhistoricaldata allthreearestillguesses whichisnotmuchofanimprovementoverasingle best guess Ifa history canbedevelopedofsimilaractivitiesfrompreviousprojects activitytimeestimatescanbeimproved Infact therequirementforgoodhistoricaldatauponwhichtobaseestimatesmakesPERTmoreappropriateforprojectsthataresomewhat repeatable Forthisreasonthethreetimeestimatesareusedprimarilyinconstructionandstandardizedengineeringprojects butseldomelsewhere Theassumptionofactivitytimes independencealsohasbeencriticized Thedurationofanactivityisinfluencedwheneverresourcesoriginallyplannedforitaretransferredtootheractivitiesthatneedexpediting TwoothercriticismsofPERTarethatitleadstooverlyoptimisticresultsandthattheBetadistributiongiveslargeerrorsinestimatingTe Criticalpathmethod CPM Time costrelationshipThecriticalpathmethodassumesthattheestimatedcompletiontimeforaprojectcanbeshortenedbyapplyingadditionalresources labor equipment capital toparticularkeyactivities Itassumesthatthetimetoperformanyprojectactivityisvariable dependingontheamountofeffortorresourcesappliedtoit Unlessstatedotherwise anygivenactivityisassumedtobeperformedatanormalworkpace Associatedwiththispaceisthenormaltime Tn howlongtheactivitywilltakeundernormalworkconditions Alsoassociatedwiththenormalpaceisthenormalcost Cn thepriceofdoingtheactivityinthenormaltime Usuallythenormalpaceisassumedtobethemostefficientandthusleastcostlypace Extendingtheactivitybeyondthenormalpacewillnotproduceanyadditionalsavingsandmightwellincreasethecost Toreducethetimetocompletetheactivity moreresourcesareappliedintheformofadditionalpersonnelandovertime Asmoreresourcesareapplied thedurationisshortened butthecostrises Whenthemaximumeffortisappliedsothattheactivitycanbecompletedintheshortestpossibletime theactivityissaidtobecrashed Thecrashconditionrepresentsnotonlytheshortestactivityduration butthegreatestcostaswell Thetime costofcompletinganactivityundernormalconditionsandcrashconditionstheoreticallydefinestwoextremepoints Thelineconnectingthesepoints calledthecostslope representsthetime costrelationship ormarginaltrade offofcost timefortheactivity Assumingasimplelinearrelationship theformulaforthecostslopeis Costslope Cc Cn Tc Tn Directcostofactivity Cc Cn Tc Tn Crash Normal Slowerthannormal Costslope Durationofactivity ReducingprojectdurationThecost slopeconceptcanbeusedtodeterminethemostefficientwayofshorteningaproject ShortestprojectdurationThestep by stepreductioneventuallyleadstotheshortestpossibleprojectduration Anotherwayistocrashallactivitiesatonce Thenstretchorincreaseanynon criticalactivitybyacertainamountwithoutextendingtheproject TotalprojectcostThecostofconductingaprojectincludesdirectactivitycostsandindirectcostssuchasadministrativeandoverheadcharges Usuallyindirectcostsareafunctionof andincreaseproportionallyto thedurationoftheproject Inotherwords indirectcosts incontrasttodirectcosts decreaseastheprojectdurationdecreases Projectcost Total direct indirect Directcost Optimumduration Projectduration Indirectcost Inadditiontodirectandindirectcosts anothercostthatinfluencestotalprojectcostisanycontractualincentivesuchasapenaltychargeorabonuspayment Apenaltychargeisalatefeeimposedonthecontractorfornotcompletingafacilityorproductontime Abonuspaymentisareward acashinducement forcompletingtheprojectearly Projectcost Total Penalty Projectduration Total incentive 0 0 Bonus Incentives Contractagreement 五 成本计划1 积极的成本计划对不同方案的技术经济分析建设成本 运营成本全过程的成本计划管理项目赢利最大化资金的供应 总投资按目标分解 累计并对比目标 设计 工作量定义 分项估 预 算费用 2 成本计划过程 InputsScopedefinitionTimetoprepareQualityofcostdataEstimatorskill Estimateaccuracy Anestimate saccuracydependsonthequalityofkeyinputs 3 计划成本的确定 固定资产投资 设备及工器具购置费 建安工程费 工程建设其他费用 预备费 基本预备费 涨价预备费 建设期贷款利息 投调税 建筑安装工程费用的项目组成与计算 建筑安装工程费用项目组成 直接费 间接费 税金 利润 直接工程费 措施费 规费 企业管理费 前期策划阶段的估算参照过去同类工