Construction Management full lecture note-By Melese Mengistu.pdf

A project is defined, whether it is in construction or not, by the
following characteristics:
 A defined goal or objective, Specific tasks to be performed, A
defined beginning& end, and Resources being consumed.
 Construction industry is different from other industries by its size, built
on-site, and generally unique.
 Projects begin with a stated goal established by the owner and
accomplished by the project team.

1. Construction Management [CENG 5194]
Civil Engineering Department
By: Melese Mengistu (MSc. Construction Engineering and Management)
Lecturer at Dire Dawa University Institute Of Technology-School Of
Civil Engineering & Architecture
E-mail: [email protected]

2. Construction Management [CENG 5194]
Chapter 1
Introduction
Lecture # 1
2 by Melese M. DDU, SCEA

3. Construction Project
Aprojectisdefined,whetheritisinconstructionornot,bythe
followingcharacteristics:
Adefinedgoalorobjective,Specifictaskstobeperformed,A
definedbeginning&end,andResourcesbeingconsumed.
Constructionindustryisdifferentfromotherindustriesbyitssize,built
on-site,andgenerallyunique.
Projectsbeginwithastatedgoalestablishedbytheownerand
accomplishedbytheprojectteam.
3 by Melese M. DDU, SCEA

4. Cont…
Anyseriesofconstructionactivitiesandtasksthat:.
Haveaspecificobjectivetobecompletedwithincertain
specifications.
Havedefinedstartandenddates
Havefundinglimits
Consumehumanandnonhumanresources
Generallyprojectis‘‘atemporaryeffort/endeavorundertakento
createauniqueproduct,service,orresult’’.
4 by Melese M. DDU, SCEA

5. Need for Construction Project Management
Theconstructionindustryisthelargestindustryintheworld.
Itismoreofaservicethanamanufacturingindustry.
Growthinthisindustryinfactisanindicatoroftheeconomicconditionsofa
country.
Thisisbecausetheconstructionindustryconsumesawideemploymentcircleof
labor.
Whilethemanufacturingindustryexhibithigh-qualityproducts,timelinesofservice
delivery,reasonablecostofservice,andlowfailurerates,theconstructionindustry,
ontheotherhand,isgenerallytheopposite.
Mostprojectsexhibitcostoverruns,timeextensions,andconflictsamongparties.
5 by Melese M. DDU, SCEA

6. Magnificent projects with huge cost overruns
6 by Melese M. DDU, SCEA
Ingeneral,theconstructionindustryismorechallengingthanother
industriesdueto:
Itsuniquenature;everyprojectisone-ofakind;manyconflictingparties
areinvolved;projectsareconstrainedbytime,moneyandquality;and
highrisk.

7. What is Construction Project Management
7 by Melese M. DDU, SCEA
ConstructionProjectmanagementistheplanning,organizing,leading,
staffingandcontrollingofallaspectsofaproject,toachievetheproject’s
objective.
managementisusuallyconsideredtohavefivefunctionsorprinciples:
Planning
Themanagementfunctionthatinvolvesanticipatingfuturetrendsand
determiningthebeststrategiesandtacticstoachieveorganizational
objectives.

8. Cont…
8 by Melese M. DDU, SCEA
Organizing
Thestructuringofresourcesandactivitiestoaccomplishobjectivesin
anefficientandeffectivemanner.Matchingresource&work
Staffing
Determininghumanresourceneeds,recruits,selects,trains,and
developshumanresourcesforjobscreatedbyanorganization.
Itisundertakentomatchpeoplewithjobssothattherealizationof
theorganization’sobjectiveswillbefacilitated

9. Cont…
9 by Melese M. DDU, SCEA
Leading
Influencingotherstoengageintheworkbehaviorsnecessarytoreach
organizationalgoals”.
Creatingasharedcultureandvalues,communicatinggoalstoemployees
throughouttheorganization,andinfusingemployeestoperformatahigh
level.
Controlling
processofascertaining/checkingwhetherorganizationalobjectiveshave
beenachieved;ifnot,whynot;anddeterminingwhatactivitiesshouldthen
betakentoachieveobjectivesbetterinfuture.

10. 14 Principles of Management(by Henry Fayol)
10 by Melese M. DDU, SCEA

11. Cont…
11 by Melese M. DDU, SCEA
1.Workdivision
Specializationallowstheindividualtobuildupexperience,andto
continuouslyimprovehisskills.Therebyhecanbemoreproductive.
2.Authority
Therighttoissuecommands,alongwithwhichmustgothebalanced
responsibilityforitsfunction.
3.Discipline
Employeesmustobey,butthisistwo-sided:employeeswillonlyobeyorders
ifmanagementplaytheirpartbyprovidinggoodleadership.

12. Cont…
12 by Melese M. DDU, SCEA
4.Unityofcommand
Eachworkershouldhaveonlyonebosswithnootherconflictinglinesofcommand.
5.UnityofDirection
Peopleengagedinthesamekindofactivitiesmusthavethesameobjectivesina
singleplan.
Thisisessentialtoensureunityandcoordinationintheenterprise.
Unityofcommanddoesnotexistwithoutunityofdirectionbutdoesnot
necessarilyflowsfromit.
6.Subordinationofindividualinterest
Managementmustseethatthegoalsofthefirmsarealwaysparamount

13. Cont…
13 by Melese M. DDU, SCEA
7.Payment/Remuneration
Paymentisanimportantmotivatoralthoughbyanalysinganumberofpossibilities,Fayol
pointsoutthatthereisnosuchthingasaperfectsystem
8.Centralization(OrDecentralization)
Thisisamatterofdegreedependingontheconditionofthebusinessandthequalityofits
personnel.
9.Scalarchain(LineofAuthority)
Ahierarchyisnecessaryforunityofdirection.Butlateralcommunicationisalso
fundamental,aslongassuperiorsknowthatsuchcommunicationistakingplace.Scalar
chainreferstothenumberoflevelsinthehierarchyfromtheultimateauthoritytothe
lowestlevelintheorganization.Itshouldnotbeover-stretchedandconsistoftoo-many
levels

14. Cont…
14 by Melese M. DDU, SCEA
10.Order
Bothmaterialorderandsocialorderarenecessary.Theformerminimizeslosttimeand
uselesshandlingofmaterials.Thelatterisachievedthroughorganizationand
selection.
11.Equity
Inrunningabusinessa‘combinationofkindlinessandjustice’isneeded.Treating
employeeswellisimportanttoachieveequity.
12.StabilityofTenureofPersonnel
Employeesworkbetterifjobsecurityandcareerprogressareassuredtothem.
Aninsecuretenureandahighrateofemployeeturnoverwillaffecttheorganization
adversely.

15. Cont…
15 by Melese M. DDU, SCEA
13.Initiative
Allowingallpersonneltoshowtheirinitiativeinsomewayisasourceofstrength
fortheorganization.
Eventhoughitmaywellinvolveasacrificeof‘personalvanity’onthepartofmany
managers.
14.EspritdeCorps
Managementmustfosterthemoraleofitsemployees.
Hefurthersuggeststhat:“realtalentisneededtocoordinateeffort,encourage
keenness,useeachperson’sabilities,andrewardeachone’smeritwithoutarousing
possiblejealousiesanddisturbingharmoniousrelations.”

16. Construction Project Management Process
16 by Melese M. DDU, SCEA
Project integration management
Project scope management
Project time management
Project cost management
Project human resource management
Project communication management
Project risk management
Project quality management
Project procurement management

17. Cont…
17 by Melese M. DDU, SCEA

18. Cont…
18 by Melese M. DDU, SCEA

19. Cont…
19 by Melese M. DDU, SCEA

20. The project management triangle
20 by Melese M. DDU, SCEA

21. Historical Aspect, Recent Trends and Future Prospects of
Ethiopian construction industry
21
Modernconstructionhoweverhadstartedduringtheregionof
EmperorMenilikII(TheroadfromAsmaratoAddisAbaba).
Italyduringitsinvasion(1936-1941)hadalsocontributedtothe
developmentoftheconstructionindustry.
Ithadconstructedabout6000kmofroads.
AfterItalianinvasion,thefirstMinistrycalled“Ministryof
CommunicationandPublicWorks’’wasestablishedduringthe
Imperialregime.
Nowadaysministryofconstructionisestablished.
by Melese M. DDU, SCEA

22. Recent Trends and Future Prospects
22 by Melese M. DDU, SCEA
Ethiopiaengagedinmassiveconstructionofmegainfrastructuresto
satisfylargedemandofitspeople.
Road Construction
Railway Construction
Hydropower Development
Wind power Development
Sugar plants
Irrigation Projects
Industry zones
Housing Developments

23. Current status of the Ethiopian construction sector
23 by Melese M. DDU, SCEA
ThegeneralstateofthedomesticconstructionindustryinEthiopiais
characterizedbythefollowingfivemajordeficiencies:
Aninadequatecapitalbase;
Oldandlimitednumbersofequipment;
Lowlevelsofequipmentavailabilityandutilization;
Deficienciesintechnical,managerial,financialand
entrepreneurialskills;and
Insufficientandineffectiveuseoflabor-based
constructionandmaintenancetechnology

24. Major categories of construction industry
24 by Melese M. DDU, SCEA
Aconstructionisaprocessofconstructingsomethingbymanforone
purposeoranother.
Itmaybearoad,bridge,adam,adwellingplace,anairport,a
commercialbuilding,etc.
Thebroadspectrumofconstructedfacilitiesmaybeclassifiedintofour
majorcategories,eachwithitsowncharacteristics:
A.ResidentialHousingConstruction:
Includessingle-familyhouses,multi-familydwellings,andhighriseapartments.
Theresidentialhousingmarketisheavilyaffectedbygeneraleconomic
conditions,taxlaws,andthemonetaryandfiscalpolicy.

25. Cont…
25 by Melese M. DDU, SCEA
B.InstitutionalandCommercialBuildingConstruction:
Encompassesagreatvarietyofprojecttypesandsizes,suchasschoolsand
universities,medicalclinicsandhospitals,recreationalfacilitiesandsportstadiums,
retailchainstoresandlargeshoppingcenters,warehousesandlightmanufacturing
plants,andskyscrapersforofficeandhotels.
Becauseofthehighercostsandgreatsophisticationincomparisonwithresidential
housing,thismarketsegmentissharedbyfewercompetitors.
C.SpecializedIndustrialconstruction:
Involvesverylargescaleprojectswithahighdegreeoftechnologicalcomplexity,
suchasoilrefineries,steelmills,chemicalprocessingplantsandnuclearplants.

26. Cont…
26 by Melese M. DDU, SCEA
Longrangedemandforecastingisthemostimportantfactorsincesuch
projectsarecapitalintensiveandrequireconsiderableamountofplanning
andconstructiontime.
D.Infrastructureandheavyconstruction:
Includesprojectssuchashighways,masstransitsystems,tunnels,bridges,
pipelines,dams,drainagesystemsandsewagetreatmentplants.
Mostoftheseprojectsarepubliclyownedandthereforefinancedbyeither
throughbonds,taxes,grantsoraids.
Thiscategoryofconstructionischaracterizedbyahighdegreeof
mechanization.

27. Construction Projects Participants
27 by Melese M. DDU, SCEA
TheOwner(TheClient):Theowneristheindividualororganizationfor
whomaprojectistobebuiltunderacontract.
DutyoftheClient
Demand for the product. For example for the building project:
Availability and cost of land,
Location & accessibility
Price
Required Infrastructure
Legal constraints
Current & future development
Soil characteristics of land
Site preparation (right of way)
Permits

28. Cont…
28 by Melese M. DDU, SCEA
Consultant
The consultants’ team shall:
Ascertain, interpret and formulate the client’s requirement into an
understandable project.
Design the project to much requirements and constraints
Assess client’s cost limit to decide on materials & the like.
Prepare contract documents.
Supervise the project and constantly inform the client on the progress
Approve payments and Resolve contractual disputes
Issue provisional and final acceptance certification

29. Cont…
29 by Melese M. DDU, SCEA
Contractor
Responsibility of contractors:
Carry out a full site investigation prior to submission of tender,
Submit tender,
Plan, Program, Control the construction process.
Notify the consultant about delays, discrepancies/disagreement,
Effect all payments to his employees, suppliers, subcontractors,
Rectify/repair all defects on completion of works, etc
Provide post occupancy repair & maintenance if required.

30. Cont…
30 by Melese M. DDU, SCEA
Public sector clients
Central Government Offices (Ministries)
Local Authorities (Regional or Town)
Public Corporations
A. Statutory Authorities
These bodies offer technical advice during design and construction in their respective
areas.
E.g. EEPCO, AAWSA, Fire Authority -requires meeting their specific requirements.
Thus early information to these authorities is required.
B. Municipalities and Government Authorities
These bodies offer the basic Land permit and building permit.

31. Cont…
31 by Melese M. DDU, SCEA
TheDesignProfessionals:Themajorroleofthedesignprofessionalisto
interpretorassisttheownerindevelopingtheproject’sscope,budget,and
scheduleandtoprepareconstructiondocuments.
Architect:Anarchitectisanindividualwhoplansanddesignbuildingsand
theirassociatedlandscaping
Engineer:Thetermengineerusuallyreferstoanindividualorafirmengaged
inthedesignorotherworkassociatedwiththedesignorconstruction.
Engineering-ConstructionFirm:Anengineering-constructionfirmisatypeof
organizationthecombinesbotharchitect/engineeringandconstruction
contracting

32. Cont…
32 by Melese M. DDU, SCEA
TheConstructionProfessionals:
TheconstructionsProfessionalarethepartiesthatresponsiblefor
constructingtheproject.
Theprimecontractorisresponsiblefordeliveringacompleteproject
inaccordancewiththecontractdocuments.
TheProjectManager:istheindividualchargedwiththeoverall
coordinationoftheentireconstructionprogramfortheowner.
Theseincludeplanning,design,procurement,andconstruction.

33. Cont…
33 by Melese M. DDU, SCEA
Amonghis/herduties:
Cleardefinitionsofthegoalsoftheproject.
Investigatealternativesolutionsfortheproblems.
Developadetailedplantomaketheselectedprogramreality.
Implementtheplanandcontroltheproject.
ConstructionManager:Theconstructionmanagerisresponsiblefor
administeringtheon-siteerectionactivities,designcoordination,
properselectionofmaterialsandmethodsofconstruction,contracts
preparationforaward,costandschedulinginformationandcontrol.

34. Project Life Cycle
34 by Melese M. DDU, SCEA
Aprocessthroughwhichaprojectisimplementedfrombeginningtoend.
Thesolutionsatvariousstagesarethenintegratedtoobtainthefinaloutcome.
Althougheachstagerequiresdifferentexpertise,itusuallyincludesboth
technicalandmanagerialactivitiesintheknowledgedomainofthespecialist.
Allstagesfromconceptualplanningandfeasibilitystudiestotheacceptance
ofafacilityforoccupancymaybebroadlylumpedtogetherandreferredto
astheDesign/Constructprocess.
Thereisnosinglebestapproachinorganizingprojectmanagementthroughout
aproject'slifecycle.

35. 1. Preconstruction phase
35 by Melese M. DDU, SCEA
Project Feasibility study
This identifies project constraints, alternatives and related assumptions
applied to the end product to be developed.
Project feasibility is characterized by four basic components:
Business Problem Description.
Approach Overview to be used to develop.
Potential Solutions of the problem.
Preliminary Recommendations.

36. Cont…
36 by Melese M. DDU, SCEA
Conceptualdesign:
Veryimportantfortheowner.
Duringthisstagetheownerhireskeyconsultantsincludingthedesignerand
projectmanager,selectstheprojectsite,andestablishaconceptual
estimate,schedule,andprogram.
Theownermustgatherasmuchinformationaspossibleabouttheproject
andThemostimportantdecisionistoproceedwiththeprojectornot.
Schematicdesign:theprojectteaminvestigatesalternatedesignsolutions,
materialsandsystems.
Completionofthisstagerepresentsabout30%ofthedesigncompletion.

37. Cont…
37 by Melese M. DDU, SCEA
Designdevelopment:Designingthemainsystemsandcomponentsoftheproject.
Goodcommunicationbetweenowner,designer,andconstructionmanageriscritical
duringthisstagebecauseselectionsduringthisdesignstageaffectproject
appearance,constructionandcost.
Contractdocuments:
Finalpreparationofthedocumentsnecessaryforthebidpackagesuchasthe
drawings,specifications,generalconditions,andbillofquantities.
Alldocumentsneedtobecloselyreviewedbytheconstructionmanagerand
appropriateownerpersonneltodecreaseconflicts,andchanges.
Withthecontractdocumentsarealmostcomplete;adetailedandcompletecost
estimatefortheprojectcanbedone

38. 2. Procurement phase (Bidding and award phase)
38 by Melese M. DDU, SCEA
Theprojectformallytransitsfromdesignintoconstruction.
Thisstagebeginswithapublicadvertisementforallinterested
biddersoraninvitationforspecificbidders.
Infast-trackprojects,thisphaseoverlapswiththedesignphase.
Iftheprojectisphased,eachworkpackagewillbeadvertisedand
bidoutindividually.
Itisveryimportantstagetoselecthighlyqualifiedcontractors.Itis
notwisetoselecttheunder-bidcontractors

39. 3.Construction phase
39 by Melese M. DDU, SCEA
Theactualphysicalconstructionoftheprojectstage.
Thisstagetakestheprojectfromprocurementthroughthefinalcompletion.
Itisthetimewherethebulkoftheowner’sfundswillbespent.
Itistheoutcomeofallpreviousstages(i.e.,goodpreparationmeans
smoothconstruction).
Theconsultantwillbedeployedforcontractadministrationand
constructionsupervision.
Changesduringconstructionmayhindertheprogressoftheproject

40. 4. Closeout phase
40 by Melese M. DDU, SCEA
Transitionfromdesignandconstructiontotheactualuseoftheconstructedfacility.
Inthisstage,themanagementteammustprovidedocumentation,shopdrawings,
as-builtdrawings,andoperationmanualstotheownerorganization.
Theas-builtdrawingsaretheoriginalcontractdrawingsadjustedtoreflectallthe
changesthatoccurred.
Assessmentoftheprojectteam’sperformanceiscrucialinthisstageforavoiding
mistakesinthefuture.
Actualactivitycostsanddurationsshouldberecordedandcomparedwiththat
wasplanned.Thisupdatedcostsanddurationswillserveasthebasisforthe
estimatingandschedulingoffutureprojects.

41. Cont…
41 by Melese M. DDU, SCEA
Provisional acceptance
the client accepts the completed works on provisional basis for a period one year.
During this period all payments except the retention money (10%) are paid.
Final acceptance
At this stage the owner completely accepts the works executed and the retention
money is released to the contractor.
But if default found during this period, the owner can oblige the contractor to
work out that default or the client himself worked it out from the retention money.
The contractor is assumed to have completed his contractual obligation from this
time on.

42. Cont…
42 by Melese M. DDU, SCEA

43. Project Delivery Methods
43 by Melese M. DDU, SCEA
Itishowprojectpartiesareinvolvedintheprojectandhowtheyinteract
witheachother.
Itcanbefacilitatedconsideringthefollowingfactors:
•Sizeandnatureoftheworkpackageswithintheproject.
•Selectionofthedesignteamformin-houseresourcesexternal
consultantsorcontractors.
•Processofsupervisionofconstruction.
•Restrictionsuponusingcombinationoforganizationalstructureswithin
theproject.
•Expertisewhichtheclientwishestocommittotheproject.

44. 1.Traditional approach
44 by Melese M. DDU, SCEA
Themostcommonapproachincivilengineeringprojectsinwhichthe
designhastobecompletedbeforeconstructioncanstart.
Designandconstructionareusuallyperformedbytwodifferentparties
whointeractdirectlyandseparatelywiththeowner.
Advantages:
Pricecompetition
Totalcostisknownbeforeconstructionstarts
Welldocumentedapproachusedinmostgovernmentprojects.
Disadvantages
LongtimeandConflictbetweenowner,contractorandA/E

45. 2. Direct labor
45 by Melese M. DDU, SCEA
Inthisapproach,ownerorganizationperformsboththedesignand
constructionusingitsin-houselaborforce.
Usedbylargeauthorities
Theownerperformsboththedesignandtheconstruction
Mayuseconsultantsforsomespecializeddesigns
Mostsuitableforsmallprojects
Canbeusedwhenexpertiseareavailable
Lowriskprojects
Inadequatescopedefinition

46. 3.Design-build
46 by Melese M. DDU, SCEA
Inthisapproach,asingleorganizationisresponsibleforperforming
bothdesignandconstruction.
Advantages:
Onlyonecontractused
Minimumownerinvolvement
Usedforfast-trackprojectsinordertoreducetime
Co-ordinationbetweendesignandconstructionandeasierinimplementing
thechanges
Disadvantages
Costmaynotbeknownuntilendoftheconstruction
Highrisktocontractorandmorecosttoowner
Design-buildcompanymayreducequalitytosavecost

47. 4.Turnkey
47 by Melese M. DDU, SCEA
Thisapproachissimilartothedesign-buildapproachbutwiththe
organizationbeingresponsibleforperformingbothdesign,
construction,know-how(ifany),andprojectfinancing.
Ownerpaymentisthenmadeatthecompletion(whenthecontractor
turnsoverthe“key”).

48. 5. Build-operate-transfer (BOT)
48 by Melese M. DDU, SCEA
Inthisapproach,abusinessentityisresponsibleforperformingthedesign,
construction,long-termfinancing,andtemporaryoperationoftheproject.
Attheendoftheoperationperiod,whichcanbemanyyears,operation
oftheprojectistransferredtotheowner
Thisapproachhasbeenextensivelyusedinrecentyearsandisexpected
tocontinue.
Thisapproachhasalsobeenusedextensivelyinlargeinfrastructure
projectsfinancedbytheWorldBankinpartsoftheworldthatcannot
affordthehighinvestmentcostofsuchprojects.

49. Cont…
49 by Melese M. DDU, SCEA
Thisdeliverysystemisadvantageousbecauseofthreemajorfactors:
Itminimizesowners’scarcityoffinancialresources;
Itdevoidofconsiderablerisksfromtheprojectownersandlessen
regulatoryactivities;and
Thefacilityiswelloperatedandtransferredwithfreeofchargeor
minimumcompensationstoprojectowners.
TheincreasingpopularityoftheBOTprojectislargelyduetoashortage
ofpublicfundingandtheopinionthatthefacilitywillbemoreefficiently
managedbyaprivateentity.

50. 6. Professional construction management (PCM)
50 by Melese M. DDU, SCEA
Inthisapproach,theownerappointsaPCMorganization(also
knownasConstructionManagementorganization)tomanageand
coordinatethedesignandconstructionphasesofaprojectusinga
Teamworkapproach.
TheuseofPCMapproach,therefore,shouldbeconsideredwhen:
Thereisaneedfortimesaving,
Flexibilityfordesignchangesisrequired,and
Ownerhasinsufficientmanagementresources.

51. 7. Contractual relationships
51 by Melese M. DDU, SCEA
Withineachprojectdeliverymethod,thecontractualrelationships
amongtheprojectparticipantscantakevariousarrangements
Theownerneedstomakeadecisionregardingtheproper
arrangementthatsuitstheprojectandthepartiesinvolved.
Thedifferentcontractualrelationshipsassociatedwithvarious
projectdeliverymethodsareillustratedinthefollowingFigures.

52. Cont…
52 by Melese M. DDU, SCEA

53. Cont…
53 by Melese M. DDU, SCEA

54. End of Chapter 1
Introduction
Lecture # 1
Thank You!!!
Construction Management [CENG 5194]
by Melese M. DDU, SCEA

55. Construction Management [CENG 5194]
Civil Engineering Department
By: Melese Mengistu (MSc. Construction Engineering and Management)
Lecturer at Dire Dawa University Institute Of Technology-School Of
Civil Engineering & Architecture
E-mail: [email protected]

56. Construction Management [CENG 5194]
Chapter 2 and 3
Project Planning and Scheduling
Lecture # 2 # 3
2 by Melese M. DDU, SCEA

57. Planning and Scheduling
3 by Melese M. DDU, SCEA

58. Planning and Scheduling
4 by Melese M. DDU, SCEA
Planningandschedulingaretwotermsthatareoftenthoughtofassynonymous,
butTheyarenot!
Schedulingisjustonepartoftheplanningeffort.
Projectplanningservesasafoundationforseveralrelatedfunctionssuchas
costestimating,scheduling,andprojectcontrol.
Projectschedulingisthedeterminationofthetimingandsequenceof
operationsintheprojectandtheirassemblytogivetheoverallcompletiontime

59. Cont…
5 by Melese M. DDU, SCEA
Planningistheprocessofdetermininghowaprojectwillbe
undertaken.Itanswersthequestions:
The Plan
What
How
much
By
whom
where
Why
How
when

60. Why Plan and Schedule Projects ?
6 by Melese M. DDU, SCEA
To calculate the project completion.
To calculate the start or end of a specific activity.
To predict and calculate the cash flow .
To evaluate the effect of changing orders .
To improve work efficiency.
To resolve delay claims , this is important in critical path method
‘CPM’ discussed later..
To serve as an effective project control tool .

61. Project Planning Methods
7 by Melese M. DDU, SCEA
1.Bar(Gantt)Charts
Abarchartis‘‘agraphicrepresentationofprojectactivities,shownina
time-scaledbarlinewithnolinksshownbetweenactivities’’
Thebarmaynotindicatecontinuousworkfromthestartoftheactivityuntil
itsend.Or
Noncontinuous(dashed)barsaresometimesusedtodistinguishbetween
realwork(solidline)andinactiveperiods(gapsbetweensolidlines)
Beforeabarchartcanbeconstructedforaproject,theprojectmustbe
brokenintosmaller,usuallyhomogeneouscomponents,eachofwhichis
calledanactivity,oratask.

62. Cont…
8 by Melese M. DDU, SCEA

63. Cont…
9 by Melese M. DDU, SCEA
Advantages Of Bar Charts
Time-scaled and Simple to prepare
Can be more effective and efficient if CPM based -Still the most
popular method
Bars can be dashed to indicate work stoppage.
Can be loaded with other information (budget, man hours, resources,
etc.)
Disadvantages Of Bar Charts
Does not show logic
Not practical for projects with too many activities

64. Cont…
10 by Melese M. DDU, SCEA
BarChartsLoadedwithMoreInfo.Suchas:budget,manhoursand
resources.
500$
220$
400$
850$
140$
500$
900$
10 12 7 11 10 9 15

65. 2. Work Breakdown Structure (WBS)
11 by Melese M. DDU, SCEA
TheWBSishierarchicalstructurewhichisdesignedtologically
subdivideallthework-elementsoftheprojectintoagraphical
presentation.
Thefullscopeofworkfortheprojectisplacedatthetopofthe
diagram,andthensub-dividedsmallerelementsofworkateach
lowerlevelofthebreakdown.
AtthelowestleveloftheWBStheelementsofworkiscalleda
workpackage.

66. Cont…
12 by Melese M. DDU, SCEA
Alistofproject’sactivitiesisdevelopedfromtheworkpackages.
EffectiveuseoftheWBSwilloutlinethescopeoftheprojectandthe
responsibilityforeachworkpackage.
Thereisnotnecessarilyarightorwrongstructurebecausewhatmay
beanexcellentfitforonedisciplinemaybeanawkwardburdenfor
another.

67. Steps to develop a project plan by WBS
13 by Melese M. DDU, SCEA
1.Definethescopeofwork,methodstatement,andsequenceofwork.
2.Generatetheworkbreakdownstructure(WBS)toproduceacompletelistof
activities.
3.Developtheorganizationbreakdownstructure(OBS)andlinkitwithwork
breakdownstructureandidentifyresponsibilities.
4.Determinetherelationshipbetweenactivities.
5.Estimateactivitiestimeduration,costexpenditure,andresourcerequirement.
6.Developtheprojectnetwork.

68. Cont…
14 by Melese M. DDU, SCEA

69. Example
15 by Melese M. DDU, SCEA
Figurebelowshowsadouble-spanbridge.Breaktheconstructionworks
ofthebridgeintoactivities.Theplanwillbeusedforbiddingpurposes.

70. Cont…
16 by Melese M. DDU, SCEA
Alistofactivities

71. Cont…
17

72. Activities Relationships
18 by Melese M. DDU, SCEA
In order to identify the relationships among activities, the planning team needs to
answer the following questions for each activity in the project:
Which activities must be finished before the current one can start?
What activities may be constructed concurrently with the current one?
What activities must follow the current one?
For example, if activity A precedes activity B, activity B precedes activity C, and
activity C precedes activity A, then the project can never be started or completed.

73. Relationships Between Activities
19 by Melese M. DDU, SCEA
Activities represented by nodes and links that allow the use of four
relationships:
1) Finish to Start –FS
2) Start to Finish –SF
3) Finish to Finish –FF
4) Start to Start –SS

74. Determination of the relationships between activities
20 by Melese M. DDU, SCEA

75. Determination of the relationships between activities
21 by Melese M. DDU, SCEA

76. 3. Networks
22 by Melese M. DDU, SCEA
Anetworkisalogicalandchronologicalgraphicrepresentationofthe
activities(andevents)composingaproject.
Networkdiagramsarethepreferredtechniqueforshowingactivity
sequencing.
Twoclassicformats:-
AOA:ActivityonArrowand
AON:ActivityonNode
Thereis1start&1endevent
Timegoesfromlefttoright

77. Arrow Diagramming Method (ADM)
23 by Melese M. DDU, SCEA
Also called activity-on-arrow (AOA) network diagram or (I-J) method (because
activities are defined by the form node, I, and the to node, J)
Activities are represented by arrows.
Nodes or circles are the starting and ending points of activities.
Can only show finish-to-start dependencies

78. Cont…
24 by Melese M. DDU, SCEA
Basic Logic Patterns for Arrow Diagrams

79. Cont…
25 by Melese M. DDU, SCEA

80. Cont…
26 by Melese M. DDU, SCEA
Draw the arrow network for the project given next.

81. Cont…
27 by Melese M. DDU, SCEA

82. Cont…
28 by Melese M. DDU, SCEA
Dummy activity (fictitious)
•Used to maintain unique numbering of activities.
•Used to complete logic, duration of “0”

83. Cont…
29 by Melese M. DDU, SCEA
Draw the arrow network for the project given next.

84. Cont…
30 by Melese M. DDU, SCEA

85. Node Networks Method (AON)
31 by Melese M. DDU, SCEA
Also called activity-on-node (AON) network diagram.
Activities are represented by node.
arrows are the starting and ending points of activities.

86. Cont…
32 by Melese M. DDU, SCEA

87. Node Format
33 by Melese M. DDU, SCEA
ES-Earliest start
EF-Earliest finish
LS-Latest start
LF-Latest finish
TT-Total float
FF-Free float
Activity Name
Activity ID
Duration
ES EF
LS LF
TF FF

88. Cont…
34 by Melese M. DDU, SCEA
Draw the node network for the project given next.

89. Cont…
35 by Melese M. DDU, SCEA

90. Cont…
36 by Melese M. DDU, SCEA
Draw the node network for the project given next.

91. Cont…
37 by Melese M. DDU, SCEA
Solution

92. Cont…
38 by Melese M. DDU, SCEA
Draw the node network for the project given next.

93. Cont…
39 by Melese M. DDU, SCEA
Solution.

94. 40 by Melese M. DDU, SCEA
PROJECT SCHEDULING

95. 41 by Melese M. DDU, SCEA
Schedulingisthedeterminationofthetimingoftheactivitiescomprisingthe
projecttoenablemanagerstoexecutetheprojectinatimelymanner.
Theprojectschedulingissuedfor:
Knowing the activities timing and the project completion time.
Having resources available on site in the correct time.
Making correction actions if schedule shows that the plan will result in late
completion.
Assessing the value of penalties on project late completion.
Determining the project cash flow.
Evaluating the effect of change orders on the project completion time.
Determining the value pf project delay and the responsible parties.

96. The Critical Path Method (CPM)
42 by Melese M. DDU, SCEA
Themostwidelyusedschedulingtechniqueisthecriticalpathmethod(CPM)for
scheduling.
Thismethodcalculatestheminimumcompletiontimeforaprojectalongwiththe
possiblestartandfinishtimesfortheprojectactivities
Thus,thecriticalpathcanbedefinedasthelongestpossiblepaththroughthe
"network"ofprojectactivities.
Thedurationofthecriticalpathrepresentstheminimumtimerequiredtocomplete
aproject.
Anydelaysalongthecriticalpathwouldimplythatadditionaltimewouldbe
requiredtocompletetheproject

97. Cont…
43 by Melese M. DDU, SCEA
Criticalactivity:Anactivityonthecriticalpathanydelayonthestartor
finishofacriticalactivitywillresultinadelayintheentireproject.
Criticalpath:Thelongestpathinanetworkfromstarttofinish.This
longestpathiscalledthecriticalpath.(Ifmorethanonepathtieforthe
longest,theyallarecriticalpaths.
Apaththroughanetworkisoneoftheroutesfollowingthearrows(arcs)fromthe
startnodetothefinishnode.
Thelengthofapathisthesumofthe(estimated)durationsoftheactivitiesonthe
path.
The(estimated)projectdurationequalsthelengthofthelongestpaththroughthe
projectnetwork.

98. Cont…
44 by Melese M. DDU, SCEA
Theremaybemorethanonecriticalpathamongalltheproject
activities,socompletionoftheentireprojectcouldbedelayedby
delayingactivitiesalonganyoneofthecriticalpaths
TheCPMisasystematicschedulingmethodforaprojectnetworkand
involvesfourmainsteps:
Aforwardpathtodetermineactivitiesearly-starttimes;
Abackwardpathtodetermineactivitieslate-finishtimes;
Floatcalculations;and
Identifyingcriticalactivities.

99. Activity-On-Arrow Networks Calculations
45 by Melese M. DDU, SCEA
Theobjectiveofarrownetworkanalysisistocomputeforeacheventin
thenetworkitsearlyandlatetimings.
Thesetimesaredefinedas:
Earlyeventtime(ET)istheearliesttimeatwhichaneventcanoccur,
consideringthedurationofprecedingactivities.
Lateeventtime(LT)isthelatesttimeatwhichaneventcanoccurifthe
projectistobecompletedonschedule

100. Cont…
46 by Melese M. DDU, SCEA
Schedulethefollowingprojectwithactivityonarrownetworkdiagram

101. Forward path
47 by Melese M. DDU, SCEA
Theforwardpathdeterminestheearly-starttimesofactivities.
Theforwardpathproceedsfromthemostleftnodeinthenetworkand
movestotheright,puttingthecalculationsinsidetheshadedboxestothe
left.
Eachnodeinthenetwork,infact,isapointatwhichsomeactivitiesend
(headarrowscomingintothenode)
Thatnodeisalsoapointatwhichsomeactivitiesstart(tailarrowsof
successoractivities)
Certainly,allsuccessoractivitiescanstartonlyafterthelatestpredecessor
isfinished.

102. Cont…
48 by Melese M. DDU, SCEA
Therefore,fortheforwardpathtodeterminetheearly-start(ES)timeof
anactivity,wehavetolookattheheadarrowscomingintothestartnode
oftheactivity.
WethenhavetosettheactivityEStimeasthelatestfinishtimeofall
predecessors.

103. Preparation for the forward path
49 by Melese M. DDU, SCEA

104. Cont…
50 by Melese M. DDU, SCEA

105. Backward Path
51 by Melese M. DDU, SCEA
Thebackwardpathdeterminesthelate-finish(LF)timesofactivitiesbyproceeding
backwardfromtheendnodetothestartingnodeoftheAOAnetwork.
WeputtheLFvaluesintherightsideboxesadjacenttothenodes,asshownin
Figure.

106. Float Calculations
52 by Melese M. DDU, SCEA
The free float is amount of time that an activity can be delayed without
affecting any succeeding activity.
Total float (TF): The maximum amount of time an activity can be delayed from its
early start without delaying the entire project.
(TF) = LF –EF
= LS –ES
Free Float (FF) = ETj–ETi–d or
FF = smallest ES (of succeeding activities) –EF (of current activity)
critical path, TF=FF=0

107. CPM results
53 by Melese M. DDU, SCEA
Critical activities are : A,Dand E
Total duration = 14 days

108. Precedence Diagram Method (PDM)
54 by Melese M. DDU, SCEA
PrecedenceDiagramMethod(PDM)istheCPMschedulingmethod
usedforAONnetworksanditfollowsthesamefourstepsoftheCPM
forAOAmethod.
Example

109. Forward pass calculations
55 by Melese M. DDU, SCEA
Forwardpass:Theprocessofnavigatingthroughanetworkfromstartto
endandcalculatingthecompletiondatefortheprojectandtheearly
datesforeachactivity.
Inmathematicalterms,theESforactivityjisasfollows:
ESj=max(EFi)
where(EFi)representstheEFforallprecedingactivities.
Likewise,theEFtimeforactivityjisasfollows:
EFj=ESj+Durj
whereDurjisthedurationofactivityj

110. Cont…
56 by Melese M. DDU, SCEA

111. Backward pass calculations
57 by Melese M. DDU, SCEA
Backward pass: The process of navigating through a network from end to
start and calculating the late dates for each activity.
In mathematical terms, the late finish LF for activity j is as follows
( LFj=min(LSk)
where (LSk) represents the late start date for all succeeding activities.
Likewise, the LS time for activity j (LS j) is as follows :
LS j= LFj-Durj
where Durj is the duration of activity

112. Cont…
58 by Melese M. DDU, SCEA

113. Floats
59 by Melese M. DDU, SCEA
Totalfloat(TF):Themaximumamountoftimeanactivitycanbedelayed
fromitsearlystartwithoutdelayingtheentireproject.
TF=LS–ES
or
TF=LF-EF
or
TF=LF–Duration-ES
FreeFloat:maybedefinedasthemaximumamountoftimeanactivitycan
bedelayedwithoutdelayingtheearlystartofthesucceedingactivities
FFi=min(ESi+1)-EFi
wheremin(ESi+1)meanstheleast(i.e.,earliest)oftheearlystartdatesof
succeedingactivities

114. CPM Result
60 by Melese M. DDU, SCEA
In the previous example we can find the free float and total float for each activity as the
following :
Activity C’s free float, FF = 11 -11 = 0 days
And
Activity C’s total float, TF =16 -11= 5 days …… and so on.
Critical activity
Note : ES = LS , EF = LF , TF = FF = 0

115. Example
61 by Melese M. DDU, SCEA
PerformtheCPMcalculations,includingtheeventtimes,forthearrow
networkshownbelow.
10 30
40
20 60
C
EB
50
D
F
70
A
G
H
10
5
7
8
9
4
5
8
d1
d2

116. Cont…
62 by Melese M. DDU, SCEA
Solution

117. End of Chapter 2 and 3
Project Planning and Scheduling
Lecture # 2
Thank You!!!
Construction Management [CENG 5194]
by Melese M. DDU, SCEA

118. Construction Management [CENG 5194]
Civil Engineering Department
By: Melese Mengistu (MSc. Construction Engineering and Management)
Lecturer at Dire Dawa University Institute Of Technology-School Of
Civil Engineering & Architecture
E-mail: [email protected]

119. by Melese M. DDU, SCEA
Construction Management [CENG 5194]
Chapter 4 and 5
Stochastic Scheduling and
Project Time-cost Trade-off
Lecture # 4& # 5
2

120. by Melese M. DDU, SCEA
Stochastic Scheduling
3
Insomesituations,estimatingactivitydurationbecomesadifficulttaskdue
toambiguityinheritedinandtherisksassociatedwithsomework.
Insuchcases,thedurationofanactivityisestimatedasarangeoftime
valuesratherthanbeingasinglevalue.
Someschedulingproceduresexplicitlyconsidertheuncertaintyinactivity
durationestimatesbyusingtheprobabilisticdistributionofactivity
durations.

121. by Melese M. DDU, SCEA
Cont…
4
Thedurationofaparticularactivityisassumedtobearandom
variablethatisdistributedinaparticularfashion.
Forexample,anactivitydurationmightbeassumedtobe
distributedasanormalorabetadistributedrandomvariableas
illustratedinfollowingFigure

122. by Melese M. DDU, SCEA
Cont…
5
Thefollowingfigureshowstheprobabilityorchanceofexperiencinga
particularactivitydurationbasedonaprobabilisticdistribution.
Thebetadistributionisoftenusedtocharacterizeactivitydurations,
sinceitcanhaveanabsoluteminimumandanabsolutemaximumof
possibledurationtimes.
Thenormaldistributionisagoodapproximationtothebeta
distributioninthecenterofthedistributionandiseasytoworkwith,so
itisoftenusedasanapproximation

123. by Melese M. DDU, SCEA
Cont…
6

124. by Melese M. DDU, SCEA
Scheduling with Uncertain Durations
7
Themostcommonformalapproachtoincorporateuncertaintyinthescheduling
processistoapplythecriticalpathschedulingprocessandthenanalyzethe
resultsfromaprobabilisticperspectivereferredtoastheProgramEvaluationand
ReviewTechnique(PERT).
Usingexpectedactivitydurationsandcriticalpathscheduling,acriticalpathof
activitiescanbeidentified.
Thiscriticalpathisthenusedtoanalyzethedurationoftheprojectincorporating
theuncertaintyoftheactivitydurationsalongthecriticalpath.
Theexpectedprojectdurationequaltothesumoftheexpecteddurationsofthe
activitiesalongthecriticalpath.

125. by Melese M. DDU, SCEA
Program Evaluation and Review Technique(PERT)
8
BothCPMandPERTwereintroducedatapproximatelythesametime
and,despitetheirseparateorigins,theywereverysimilar.
ThePERTmethodsharesmanysimilaritieswithCPM.
Bothrequirethataprojectbebrokendownintoactivitiesthatcouldbe
presentedintheformofanetworkdiagramshowingtheirsequential
relationshipstooneanother.
Bothrequiretimeestimatesforeachactivity,whichareusedinroutine
calculationstodetermineprojectdurationandschedulingdataforeach
activity.

126. by Melese M. DDU, SCEA
Cont…
9
CPMrequiresareasonablyaccurateknowledgeoftimeandcostfor
eachactivity.
Inmanysituations,however,thedurationofanactivitycannotbe
accuratelyforecasted,andadegreeofuncertaintyexists
ContrarytoCPM,PERTintroducesuncertaintyintotheestimatesfor
activityandprojectdurations.

127. by Melese M. DDU, SCEA
Cont…
10
Itiswellsuitedforthosesituationswherethereiseitherinsufficient
backgroundinformationtospecifyaccuratelytimeandcostorwhere
projectactivitiesrequireresearchanddevelopment.
Themethodisbasedonthewell-known“centrallimittheorem”.
Thetheoremstatesthat:“Whereaseriesofsequentialindependent
activitieslieonthecriticalpathofanetwork,thesumoftheindividual
activitydurationswillbedistributedinapproximatelynormalfashion,
regardlessofthedistributionoftheindividualactivitiesthemselves.

128. by Melese M. DDU, SCEA
Cont…
11
PERT,unlikeCPM,usesthreetimeestimatesforeachactivity.
Thesedurationestimatesare:
Optimisticduration(o);anestimateoftheminimumtimerequiredfor
anactivityifexceptionallygoodluckisexperiencedorundermost
favorableconditions.
Mostlikelyormodaltime(m);thetimerequirediftheactivityis
repeatedanumberoftimesunderessentiallythesameconditions.
Pessimisticduration(p);anestimateofthemaximumtimerequiredif
unusuallybadluckisexperiencedorundermostunfavorableconditions

129. by Melese M. DDU, SCEA
Cont…
12
Thesethreetimeestimatesbecometheframeworkonwhichtheprobability
distributioncurvefortheactivityiserectedandManyauthorsarguethatbeta
distributionismostlyfitconstructionactivities.

130. by Melese M. DDU, SCEA
Example: Construction Company Project
13
TheConstructionCompanyhasjustmadethewinningbidof$5.4millionto
constructanewplantforamajormanufacturer.Thecontractincludesthefollowing
provisions:Apenaltyof$300,000ifContractorhasnotcompletedconstruction
within47weeksandAbonusof$150,000ifContractorhascompletedtheplant
within40weeks.
1.How can the project be displayed graphically to better visualize the activities?
2.What is the total time required to complete the project if no delays occur?
3.When do the individual activities need to start and finish?
4.Identify critical path & how much delay can be tolerated for each activity?
5.What is the probability the project can be completed in 47 weeks?

131. by Melese M. DDU, SCEA
Activity
o m p Immediate
Predecessors
A 1 2 3 —
B 2 3.5 8 A
C 6 9 18 B
D 4 5.5 10 C
E 1 4.5 5 C
F 4 4 10 E
G 5 6.5 11 D
H 5 8 17 E, G
I 3 7.5 9 C
J 3 9 9 F, I
K 4 4 4 J
L 1 5.5 7 J
M 1 2 3 H
N 5 5.5 9 K, L

132. by Melese M. DDU, SCEA
Mean and Standard Deviation
An approximate formula for the variance (
2
) of an activity is
An approximate formula for the mean (m) of an activity is

2

po
6






2

o4mp
6

133. by Melese M. DDU, SCEA
Time Estimates for Construction Project
Activity o m p Mean Variance
A 1 2 3 2
1
/
9
B 2 3.5 8 4 1
C 6 9 18 10 4
D 4 5.5 10 6 1
E 1 4.5 5 4
4
/
9
F 4 4 10 5 1
G 5 6.5 11 7 1
H 5 8 17 9 4
I 3 7.5 9 7 1
J 3 9 9 8 1
K 4 4 4 4 0
L 1 5.5 7 5 1
M 1 2 3 2
1
/
9
N 5 5.5 9 6
4
/
9

134. by Melese M. DDU, SCEA
Activity List for Construction
ActivityActivity Description
Immediate
Predecessors
Estimated
Duration (Weeks)
A Excavate — 2
B Lay the foundation A 4
C Put up the rough wall B 10
D Put up the roof C 6
E Install the exterior plumbing C 4
F Install the interior plumbing E 5
G Put up the exterior siding D 7
H Do the exterior painting E, G 9
I Do the electrical work C 7
J Put up the wallboard F, I 8
K Install the flooring J 4
L Do the interior painting J 5
M Install the exterior fixtures H 2
N Install the interior fixtures K, L 6

135. by Melese M. DDU, SCEA
Project Network

A
START
G
H
M
F
J
K L
N
Activity Code
A. Excavate
B. Foundation
C. Rough wall
D. Roof
E. Exterior plumbing
F. Interior plumbing
G. Exterior siding
H. Exterior painting
I. Electrical work
J. Wallboard
K. Flooring
L. Interior painting
M. Exterior fixtures
N. Interior fixtures
2
4
10
746
7
9
5
8
4 5
6
2
0
0FINISH
D IE
C
B

136. by Melese M. DDU, SCEA
ES and EF Times for Construction project

A
START
G
H
M
F
J
FINISH
K L
N
D IE
C
B
2
4
10
746
7
9
5
8
4 5
6
2
ES = 0
EF = 2
ES = 2
EF = 6
ES = 16
EF = 22
ES = 16
EF = 20
ES = 16
EF = 23
ES = 20
EF = 25
ES = 22
EF = 29
ES = 6
EF = 16
ES = 0
EF = 0
ES = 25
EF = 33
ES = 33
EF = 38
ES = 38
EF = 44
ES = 33
EF = 37
ES = 29
EF = 38
ES = 38
EF = 40
ES = 44
EF = 44
0
0

137. by Melese M. DDU, SCEA
LS and LF Times for construction Project

A
START
G
H
M
F
J
FINISH
K L
N
D IE
C
B
2
4
10
746
7
9
5
8
4 5
6
2
LS = 0
LF = 2
LS = 2
LF = 6
LS = 20
LF = 26
LS = 16
LF = 20
LS = 18
LF = 25
LS = 20
LF = 25
LS = 26
LF = 33
LS = 6
LF = 16
LS = 0
LF = 0
LS = 25
LF = 33
LS = 33
LF = 38
LS = 38
LF = 44
LS = 34
LF = 38
LS = 33
LF = 42
LS = 42
LF = 44
LS = 44
LF = 44
0
0

138. by Melese M. DDU, SCEA
Project Network

A
START
G
H
M
F
J
FINISH
K L
N
D IE
C
B
2
4
10
746
7
9
5
8
4 5
6
2
S = (0, 0)
F = (2, 2)
S = (2, 2)
F = (6, 6)
S = (16, 20)
F = (22, 26)
S = (16, 16)
F = (20, 20)
S = (16, 18)
F = (23, 25)
S = (20, 20)
F = (25, 25)
S = (22, 26)
F = (29, 33)
S = (6, 6)
F = (16, 16)
S = (0, 0)
F = (0, 0)
S = (25, 25)
F = (33, 33)
S = (33, 33)
F = (38, 38)
S = (38, 38)
F = (44, 44)
S = (33, 34)
F = (37, 38)
S = (29, 33)
F = (38, 42)
S = (38, 42)
F = (40, 44)
S = (44, 44)
F = (44, 44)
0
0

139. by Melese M. DDU, SCEA
Spreadsheet to Calculate ES, EF, LS, LF, SlackActivityDescription Time ES EF LS LFSlackCritical?
AExcavate 2 0 2 0 2 0 Yes
BFoundation 4 2 6 2 6 0 Yes
CRough Wall 10 6 16 6 16 0 Yes
DRoof 6 16 22 20 26 4 No
EExterior Plumbing4 16 20 16 20 0 Yes
FInterior Plumbing5 20 25 20 25 0 Yes
G Exterior Siding 7 22 29 26 33 4 No
HExterior Painting9 29 38 33 42 4 No
IElectrical Work 7 16 23 18 25 2 No
JWallboard 8 25 33 25 33 0 Yes
KFlooring 4 33 37 34 38 1 No
LInterior Painting5 33 38 33 38 0 Yes
M Exterior Fixtures2 38 40 42 44 4 No
NInterior Fixtures6 38 44 38 44 0 Yes
Project Duration44

140. by Melese M. DDU, SCEA
Calculation of Project Mean and Variance
Activities on Mean Critical PathMean Variance
A 2
1
/
9
B 4 1
C 10 4
E 4
4
/
9
F 5 1
J 8 1
L 5 1
N 6
4
/
9
Project duration m
p= 44 s
2
p= 9

141. by Melese M. DDU, SCEA
Probability of Meeting Deadline

142. by Melese M. DDU, SCEA
Probability of Meeting a Deadline
P(T≤d) P(T≤ d)
–3.0 0.0014 0 0.50
–2.5 0.0062 0.25 0.60
–2.0 0.023 0.5 0.69
–1.75 0.040 0.75 0.77
–1.5 0.067 1.0 0.84
–1.25 0.11 1.25 0.89
–1.0 0.16 1.5 0.933
–0.75 0.23 1.75 0.960
–0.5 0.31 2.0 0.977
–0.25 0.40 2.5 0.9938
0 0.50 3.0 0.9986
d
p

p
d
p

p

143. by Melese M. DDU, SCEA
Spreadsheet for PERTTime EstimatesOn Mean
Activityo m pCritical Pathm s
2
A 1 2 3 * 20.1111Mean Critical
B 23.58 * 4 1 Path
C 6 918 * 10 4 m = 44
D 45.510 6 1 s
2
= 9
E 14.55 * 40.4444
F 4 410 * 5 1P(T<=d) = 0.8413
G 56.511 7 1 where
H 5 817 9 4 d = 47
I 37.59 7 1
J 3 9 9 * 8 1
K 4 4 4 4 0
L 15.57 * 5 1
M 1 2 3 20.1111
N 55.59 * 60.4444

144. by Melese M. DDU, SCEA
27
Time-cost Trade-off
Lecture # 5

145. by Melese M. DDU, SCEA
Project Time-cost Trade-off
Reducingbothconstructionprojects’costandtimeiscriticalintoday’smarket-
driveneconomy.
Thisrelationshipbetweenconstructionprojects’timeandcostiscalledtime-cost
trade-off.
Theobjectiveofthetime-costtrade-offanalysisistoreducetheoriginalproject
duration,determinedformthecriticalpathanalysis,tomeetaspecificdeadline,
withtheleastcost.
Time-costtrade-off,infact,isanimportantmanagementtoolforovercoming
oneofthecriticalpathmethodlimitationsofbeingunabletobringtheproject
scheduletoaspecifiedduration.

146. by Melese M. DDU, SCEA
Cont…
Itmightbenecessarytofinishtheprojectinaspecifictimeto:
Finishtheprojectinapredefineddeadlinedate.
Recoverearlydelays.
Avoidliquidateddamages.
Freekeyresourcesearlyforotherprojects.
Avoidadverseweatherconditionsthatmightaffectproductivity.
Receiveanearlycompletion-bonus.
Improveprojectcashflow

147. by Melese M. DDU, SCEA
Reducingprojectdurationcanbedonebyadjustingoverlapsbetween
activitiesorbyreducingactivities’duration.
Whatisthereasonforanincreaseindirectcostastheactivityduration
isreduced?Asimplecasearisesintheuseofovertimework.
Byschedulingweekendoreveningwork,thecompletiontimeforan
activityasmeasuredincalendardayswillbereduced.
However,extrawagesmustbepaidforsuchovertimework,sothecost
willincrease.
Also,overtimeworkismorepronetoaccidentsandqualityproblemsthat
mustbecorrected,socostsmayincrease.
Cont…

148. by Melese M. DDU, SCEA
The activity duration can be reduced by one of the following actions:
Applying multiple-shifts work.
Working extended hours (over time).
Offering incentive payments to increase the productivity.
Working on week ends and holidays.
Using additional resources.
Using materials with faster installation methods.
Using alternate construction methods or sequence

149. by Melese M. DDU, SCEA
Illustration of linear time/cost trade-off
The limit beyond which an activity time cannot be shortened is known as the crash limit.
Crash Limit = D –D’ where: D = normal time (duration) D’ = crash time (duration)
Slope = (C’ –C)/(D –D’) = Crash Cost Per Unit Time

150. by Melese M. DDU, SCEA
It can be reduced by reducing the normal times of critical activities.
Reducingthecriticalactivitywiththeminimumcost-durationslopewill
yieldtheminimumcostuptothecrashlimit.
Thisdoesnotguaranteethattheprojecttimewillalsobereducedbythe
samelength,sincetheabovereductionmayhaveledtotheanew
criticalpath.
Reduction of the Project Completion Time

151. by Melese M. DDU, SCEA
Detection of New Critical Path
Tofindwhetheranewcriticalpathmayoccur,checkwhetherapositivefreefloat
ofanynon-criticalactivitybecomeszero.
Byreducingthedurationofthecriticalactivitybyonetimeunit,computethenew
freefloatsofthenon-criticalactivities.
Checkwhichoneshavereducedtheiroldpositivefreefloatsbyoneunit.
Theonewiththesmallestoldpositivefreefloatgivesthepositivefreefloatlimit.
ReductionLimit=min{crashlimit,positivefreefloatlimit}
Continuetoproceedintheabovefashionuntilallcriticalactivitiesinthelatest
criticalpathareattheircrashlimits.

152. by Melese M. DDU, SCEA
Example 1
Considerthefollowingarrowdiagramwithactivitytimesgivenin
dayswithnoindirectcostpaidondailybase.
1 4
2
3
A
D
CB
4 10
86

153. by Melese M. DDU, SCEA
The normal and crash data
Find the critical path
Find the project completion time and the corresponding cost.
If we want to complete the project in 18 days, find the best crash
time and cost.
Note our aim is to reduce completion time for various reasons
such as, to escape from liquidated damage, to recover fro
delays, to save a time for other works, and etc…ActivityNormal Time (Days)Crash Time (Days)Normal Cost ($)Crash Cost ($)
A 4 3 80 105
B 6 4 180 250
C 8 5 200 320
D 10 6 350 530

154. by Melese M. DDU, SCEA
Solution for the Critical Path
1 4
2
3
{FF = 10} A
D
CB
4 10
86
0
0
10,0
6
6
24
24
14
14
4,14

155. by Melese M. DDU, SCEA
Solution
(a)Critical Path is B, C, D.
(b)Project completion time = 24 days Project cost = 80 +
180 + 200 + 350 = $810
(c)From the given data, construct the following crash time-
cost table:Activity (I,j)Crash Limit (D - D')
Crash Cost/Day
(C' -C)/(D - D')
A(1,3) 4 - 3 = 1 (105 - 80)/(4 - 3) = 25
B(1,20 6 - 4 = 2 (250 - 180)/(6 - 4) = 35
C(2,3) 8 - 5 = 3 (320 - 200)/(8 - 5) = 40
D(3,4) 10 - 6 = 4 (530 - 350)/(10 - 6) = 45

156. by Melese M. DDU, SCEA
Cont…
Since the critical activity B has the lowest “crash cost per
day,” it becomes the first candidate for crash. The length
by which B can be reduced is found as follows:
Reduction Limit = min {crash limit,
positive FF limit}
= min {2, 10} = 2Activity (I,j)A (1,3)B (1,2)C (2,3)D (3,4)
Critical … yesyesyes
Free Float10 … … …

157. by Melese M. DDU, SCEA
Crash activity B by 2 days
1 4
2
3
{FF = 8} A
D
CB
4 10
8
6
0
0
8,0
4
4
22
22
12
12
4,12
4

158. by Melese M. DDU, SCEA
Cont…
Critical path is still B, C, D.
Project completion time = 22 days
Project cost = 810 + 2*35 = $880
Since the crash limit for critical activity B is reached,
consider activity C with the next lowest “crash cost per
day” for crash.Activity (I,j)A (1,3)B (1,2)C (2,3)D (3,4)
Critical … yesyesyes
Free Float8 … … …

159. by Melese M. DDU, SCEA
Crash C
Reduction Limit = min { 3, 8} = 3
Hence, crash activity C by 3 days.
1 4
2
3
{FF = 5} A
D
CB
4 10
86
0
0
0,5
4
4
19
19
9
9
9,4
4 5

160. by Melese M. DDU, SCEA
Cont…
Critical path is still B, C, D.
Project completion time = 19 days.
Project cost = 880 + 3*40 = $1000.
Since the crash limit for critical activity C is reached,
consider activity D with the next lowest “crash cost per
day” for crash.Activity (I,j)A (1,3)B (1,2)C (2,3)D (3,4)
Critical … yesyesyes
Free Float5 … … …

161. by Melese M. DDU, SCEA
Crash D
Reduction Limit = min {4, 5} = 4
Although we can reduce D by 4 days, it is only necessary to
reduce it by 1 day to reach our project completion goal of 18
days.
1 4
2
3
A
D
CB
4 10 9
86
0
0
5,0
4
4
18
18
9
9
9,4
4 5

162. by Melese M. DDU, SCEA
Final Answer
From the critical path calculations, we have the
following information:
Critical path is still B, C, D.
Project completion time = 18 days
Project cost = 1000 + 1*45 = $1045

163. by Melese M. DDU, SCEA
Example.Considerthefollowingtime-costrelationshipdatafora
project.Findtheleastcostschedule(optimumduration)iftheindirect
costis100birrperday.
ActivityNormal
time
Normal
cost, Birr
Crash
time,
Days
Crash
cost,
Birr
1-2
1-3
2-4
2-5
3-4
4-5
8
4
2
10
5
3
100
150
50
100
100
80
6
2
1
5
1
1
200
350
90
400
200
100
580 1340
46
Example 2

164. by Melese M. DDU, SCEA
Activit
y
Norma
l time
Normal
cost,
Birr
Crash
time,
Days
Crash
cost,
Birr
Cost
slope
A
B
C
D
E
F
4
8
5
2
10
3
150
100
100
50
100
80
2
6
1
1
5
1
350
200
200
90
400
100
100
50
25
40
60
10
18 580 1340
Solution:
The critical path = B and E. Normal duration = 18days
Total cost = Indirect cost + direct cost = 18*100 + 580 = 2380 birr
47
Cont…
start
A,4
B,8
D, 2
C,5
F,3
E,10
END

165. by Melese M. DDU, SCEA
Stage 1.
Bis the critical activity of least cost slope &Crash Bby 2 days.
Current Project Duration = 18-2 = 16 days & Current critical path: B and E
Current Total cost = (16*100) +580+(2*50) = 2280 birr
Stage 1
48
Cont…
Activit
y
Normal
time
Normal
cost,
Birr
Crash
time,
Days
Crash
cost,
Birr
Cost
slope
A
B
C
D
E
F
4
8
5
2
10
3
150
100
100
50
100
80
2
6
1
1
5
1
350
200
200
90
400
100
100
50
25
40
60
10
18 580 1340

166. by Melese M. DDU, SCEA
Stage 2.
Band E are critical activities.
Now, crash Eby 4 days only since the duration of the path A-C-F is 12 days.
Current Duration = 16-4 = 12days Current critical paths: i) B and and ii) A,C and F
Current Total cost = (12*100)+680+ (60*4) = 2120 birr
Stage 2
49
Cont…
ActivityNorma
l time
Normal
cost,
Birr
Crash
time,
Days
Crash
cost,
Birr
Cost
slope
A
B
C
D
E
F
4
8
5
2
10
3
150
100
100
50
100
80
2
6
1
1
5
1
350
200
200
90
400
100
100
50
25
40
60
10
18 580 1340

167. by Melese M. DDU, SCEA
Stage 3.
Criticalactivities:A,B,C,E,F,CrashEby1dayandCrashFby1dayeach(sincethe
durationofthepathB,DandFis11daysandalsotheactivityEcanbecrashedonly
byoneday).Currentcriticalpaths:i)BandEandii)A,CandFCurrentDuration
=12-1=11dysandCurrentTotalcost=(11*100)birr+920+
(1*300/5)+(1*20/2)=2090birr
Stage 3
50
Cont…
ActivityNorma
l time
Normal
cost,
Birr
Crash
time,
Days
Crash
cost,
Birr
Cost
slope
A
B
C
D
E
F
4
8
5
2
10
3
150
100
100
50
100
80
2
6
1
1
5
1
350
200
200
90
400
100
100
50
25
40
60
10
18 580 1340

168. by Melese M. DDU, SCEA
No further crushing is possible (since all the activities on the critical path
B and E have been crashed to the maximum extent).
Answer:Hence the optimum duration is 11 days and the least cost is 2090birr
Stage Crash Current durationDirect costIndirect costTotal cost
0 0 18 580 1800 2380
1 B by 2days 16 680 1600 2280
2 E by 4days 12 920 1200 2120
3 E and F by 1
day each
11 990 1100 2090
Table : Crashing schedule
51
Cont…

169. by Melese M. DDU, SCEA
Determinetheleastcostforexpeditingandoptimumdurationofthecontract
assumingtheindirectcostisLE125/day.
Example 3

170. by Melese M. DDU, SCEA
Solution
Boththecrashabilityandthecostslopeareshownbeneatheachactivity.
ThecriticalpathisA-C-G-Iandthecontractdurationin59days.

171. by Melese M. DDU, SCEA
Step 1
Crash“G”,by5days,butifitiscrashedbymorethan2daysanothercriticalpathwillbe
generated.Therefore,activity“G”willbecrashedby2daysonly.
AnewcriticalpathA-C-F-H-I,durationis57daysandthecostincreaseis2x60=LE120

172. by Melese M. DDU, SCEA
Step 2
CrashEither“A”atcostLE100/day,Or“C”atcostLE200/day,Or“I”at
costLE75/dayOr
“F&G”atcostLE360/day,Or“H&G”atcostLE100/day.
Activity“I”ischosenbecauseithastheleastcostslope,anditcanbe
crashedby2days.
Becauseitislastactivityinthenetwork,ithasnoeffectonotheractivities.

173. by Melese M. DDU, SCEA
Cont…
duration is 55 days
Cumulative cost increase = 120 + (2 x 75)= LE 270

174. by Melese M. DDU, SCEA
Step 3
Now,wecouldselect“A”orboth“H&G”,becausetheyhavethesamecostslope.
Activity“A”ischosentobecrashed.
New contract duration is 53 days
cumulative cost increase = 270 + (2 x 100) = LE 470.

175. by Melese M. DDU, SCEA
Step 4
Now, activities “H & G” can be crashed by 2 days each. “A” new critical path AB-D-
I will be formed.
New contract duration is 51 day.
cumulative cost increase = 470 + (2 x 100) = LE 670

176. by Melese M. DDU, SCEA
Step 5
Atthisstage,thenetworkhasthreecriticalpaths.
CrashEitherC&BatcostLE350/dayorF,G&BatcostLE510/dayActivitiesC&
Barechosenbecausetheyhavetheleastcostslope.
durationis49days.
Cumulativecostincrease=670+(2x350)
=LE1370
Now,thereisnofurthershorteningispossible

177. by Melese M. DDU, SCEA
Contract Duration and Corresponding Cost
Final answer

178. by Melese M. DDU, SCEA
End of Chapter 4 and 5
Stochastic Scheduling and
Project Time-cost Trade-off
Lecture # 3
Thank You!!!
Construction Management [CENG 5194]

179. Construction Management [CENG 5194]
Civil Engineering Department
By: Melese Mengistu (MSc. Construction Engineering and Management)
Lecturer at Dire Dawa University Institute Of Technology-School Of
Civil Engineering & Architecture
E-mail: [email protected]

180. by Melese M. DDU, SCEA
Construction Management [CENG 5194]
Chapter 6
Construction Resources management
Lecture # 6
2

181. by Melese M. DDU, SCEA
Construction Resources
3
Wehavestatedthattheprojectmanagermustcontrolcompany
resourceswithintime,cost,andperformance.Mostcompanieshave
sixresources.
Money
Manpower
Equipment
Facilities
Materials
Information/technology

182. by Melese M. DDU, SCEA
Human resource (Labour or Workmen)
4
Theseincludeprofessional,skilled,semiskilledandunskilledlaborers.
Humanresourcescanbeunderstoodintwovalues:CapacityandCapability.
Capacity-referstothequantityoflaborforthescopedefined.
Capability-referstoknowledge,technologyknow-howandskillasperthedemands
ofthescopesability.
ConstructionManagersneedtobecapableof:
Communication-Inter-personal,groupinteraction-skills
Problemsolving/Conflictresolution/NegotiationSkills
Facilitating/Decision-makingSkills
WritingskillsforProposals/Reports/ToRsand
HardSkills-Planning,Implementing,LeadingandMonitoringtools.

183. by Melese M. DDU, SCEA
Cont…
5
FinancialResources(Fund):UsuallyfundsareavailablefromamongGovernmental
institution,PrivateinstitutionsandDonorsintheformofloanorassistance.
InformationResources:Informationcanbeunderstoodintwoterms:datawhetherprocessed
ornot;anditstechnology
PhysicalResources
Materials:Materialcovers55-70%ofthetotalconstructioncost.
Equipment:Thoughtheirinitialcostishighusingequipmentarefarmorebetterthanusing
labor.
Otherassets:PhysicalInfrastructuresandOwnedLandareassetswhichcanbecollaterals
forcapitalbaseenhancementandcreditfacilitiesandareusefultodevelopthescarce
financialresourcesandgettingintobusinessaccess.

184. by Melese M. DDU, SCEA
Cont…
6
ServiceandManagement
Service
Servicessuchasacquisitionofland,provisionsofwatersupply,electric
power,communicationsystems,etc.,areverymuchnecessaryinthe
constructionindustry.
Management
Managementhascometoemployadisciplinedapproachtotheuseof
availableresources.

185. by Melese M. DDU, SCEA
Cont…
Resourcesmaybeclassifiedaccordingtotheirimportance:
ConsumableResource:suchasmaterialsthatmaybeusedonceandonceonly,or
Non-consumableResource:suchaspeople,whichmaybeusedagainandagain.
Keyresources:mostimportant,expensiveandnon-availableresourcesinthe
projectsuchasskilledlabors,orequipment.Thesetypesofresourceswillhavea
greatattentionintheresourceschedulingprocess.
Secondaryresources:resourceswhichhavenoconstraintsontheiravailability,such
asnormallabor.
Generalresources:usedbyallormostoftheactivitiesontheprojectsuchassite
overheads.Generalresourceswillnotbeincludedintheresourcemanagement

186. by Melese M. DDU, SCEA
Resources Management
Aswehaveseeninnetworkscheduling,thebasicinputstocritical-pathanalysis
aretheindividualprojectactivities,theirdurations,andtheirdependency
relationships.
TheCPMalgorithmisduration-drivenandassumesthatalltheresources
neededforthescheduleareavailable.
Thisassumption,however,isnotalwaystrueforconstructionprojectsUnder
resourceconstraints,theschedulebecomesimpractical,costandtimearenot
accurate,andresourcesmaynotbeavailablewhenneeded.
Inordertodealwithsuchissue,apropermanagementofavailableresourcesis
requiredtoadjustthescheduleaccordingly.

187. by Melese M. DDU, SCEA
Themostimportantresourcesthatprojectmanagershavetoplanandmanageon
day-to-daybasisarepeople,machines,materials,andmoney.
Obviously,iftheseresourcesareavailableinabundancethentheprojectcouldbe
acceleratedtoachieveshorterprojectduration.
Ontheotherhand,iftheseresourcesareseverelylimited,thentheresultmore
likelywillbeadelayintheprojectcompletiontime.
Ingeneral,fromaschedulingperspective,projectscanbeclassifiedaseithertime
constrainedorresourceconstrained.
Cont…

188. by Melese M. DDU, SCEA
Resource scheduling
Resourceschedulingisprioritizingandallocatingresourcesinsucha
mannerthatthereisminimalprojectdelay.
Aprojectisresourceconstrainedifthelevelofresourceavailabilitycannot
beexceeded.
Inthosesituationswhereresourcesareinadequate,projectdelayis
acceptable,butthedelayshouldbeminimal.
However,itisalsoimportanttoensurethattheresourcelimitisnot
exceededandthetechnicalrelationshipsintheprojectnetworkare
respected.

189. by Melese M. DDU, SCEA
Resource leveling (smoothing)
Theprimaryfocus,forpurposesofscheduling,intimeconstrainedprojectsis
toimproveresourceutilization.
Thisprocessiscalledresourcelevelingorsmoothing.
Itapplieswhenitisdesiredtoreducethehiringandfiringofresourcesandto
smooththefluctuationinthedailydemandofaresource,asshowninFigure
below.
Inthiscase,resourcesarenotlimitedandprojectdurationisnotallowedtobe
delayed.
Theobjectiveinthiscaseistoshiftnon-criticalactivitiesoftheoriginal
schedule,withintheirfloattimessothatabetterresourceprofileisachieved.

190. by Melese M. DDU, SCEA
Cont…
Figure : Resource leveling (smoothing)

191. by Melese M. DDU, SCEA
Resource Allocation
Resourceallocation,alsocalledresourceloading,isconcernedwithassigningthe
requirednumberofresourcesidentifiedforeachactivityintheplan.
Morethanonetypeofresourcemaybeassignedtoaspecificactivity.
Forexample,fixingsteelplatesonabridgedeckmayrequiredifferenttypesofresources
suchas:welders,laborersandacertaintypeofweldingmachine.
Fromapracticalview,resourceallocationdoesnothavetofollowaconstantpattern;
someactivitiesmayinitiallyrequirefewerresourcesbutmayrequiremoreofthesame
resourcesduringthelaterstagesoftheproject.

192. by Melese M. DDU, SCEA
Resource Aggregation
Resourceaggregationissimplythesummation,onaperiod-by-periodbasis,ofthe
resourcesrequiredtocompleteallactivitiesbasedontheresourceallocationcarriedout
previously.
Theresultsareusuallyshowngraphicallyasahistogram.
Suchaggregationmaybedoneonanhourly,daily,orweeklybasis,dependingonthetime
unitusedtoallocateresources.
Whenabarchartisused,theresourceaggregationisfairlysimpleandstraightforward.
Foragivenbarchart,aresourceaggregationchartcanbedrawnunderneaththebarchart.
However,aseparategraphwillberequiredforeachresourcetype.
Therequiredresourceunitsforeachtimeperiodarewrittenonthebarchart.

193. by Melese M. DDU, SCEA
Cont…
Thetotalnumberofresourceunitsforeachtimeperiodcanthenbesummedanda
resourceaggregationorloadchartcanbeproducedaspresentedunderneaththe
barchart.
Example

194. by Melese M. DDU, SCEA
Cont…
Thenoncriticalactivities,donothavefixedstartingandfinishingtimesbutareconstrainedby
theearliestandlateststartingandfinishingtimes.
Thissituationofferstheplannerchanceforadjustingthedemandforresources.
TheaboveFigureillustratessuchsituation,whichshowstheresourceaggregationwhenthe
activitiesscheduledontheirearlytimesandlatetimes.
Itcanbeseenthattheresourcerequirementsthatarisewhenbothearliestandlateststarttimes
areconsideredaredifferent.
Theshadedarearepresentstheresourcesrequiredbythecriticalactivities,astheseactivities
haveafixedpositionbecausetheirearlytimesequaltheirlatetime.
Resourcesaccumulateatthebeginningoftheprojectwhentheactivitiesscheduledontheirearly
time.
Resourcesaccumulateattheendoftheprojectwhentheactivitiesscheduledontheirlatetimes.

195. by Melese M. DDU, SCEA
Theproblemofresourcefluctuationappearsaftertheinitialschedulingofthe
projectwithoutconsideringtheresources.
Thepeaksandvalleysintheresourceprofileindicatehighday-to-dayvariation
intheresourcedemand.
Resourcesmoothingistheprocessthatattemptstodeterminearesource
requirementthatis"smooth"andwherepeaksandvalleysareeliminated.
Resourcelevelingheuristicsshiftnon-criticalactivitieswithintheirfloattimes
soastomoveresourcesfromthepeakperiods(highusage)tothevalleyperiods
(lowusage),withoutdelayingtheproject(i.e.,areaunderneaththeresource
profileremainsconstant).
Cont…

196. by Melese M. DDU, SCEA
Preferred resource usage

197. by Melese M. DDU, SCEA
Heuristic Procedure for Resource Smoothing
steps:
Prepare a complete activity schedule.
Draw a bar chart of the project under study based on ES timing of the
activities.
Critical activities to be drawn first (as these activities will not be moved).
Write the resource usage above each bar of the related activity.
Draw the FF as dashed line beside the upper side of the bar and the TF
beside the lower side.
Aggregate (determine the resource sum) the resources in each time period.
Calculate the total usage of resources = Σunit period usage.

198. by Melese M. DDU, SCEA
Calculatetheaverageresourceusage=Σusage/utilizationperiod.
Shiftnon-criticalactivitieswithintheirFFfirst,thentheirTFtodecreasethe
peaksandraisethevalleys.
Reviseactivitiesfloats.
Aggregateresourcesineachtimeperiodaftershiftinganyactivity.
Whenshiftingactivities,itispreferredtostartwiththeactivitiesthathave
nosuccessors,asshiftingtheseactivitieswillnotaffectotheractivities.
Also,byshiftingtheseactivities,afloatwillbecreatedforits
predecessors.
Shiftactivitiesonlythatwillenhancetheresourceprofile.
Cont…

199. by Melese M. DDU, SCEA
Example
Activity Activity Duration
(Weeks)
PredecessorsResource
(units/week)
A
B
C
D
E
F
G
H
I
J
K
L
M
N
0
2
5
3
2
6
6
6
4
2
7
3
2
2
-
A
A
A
B
B
C
D
D
E, F
F, G
B, H
B, H, I
J, K, L,M
0
0
2
2
1
2
3
1
0
4
2
2
4
0

200. by Melese M. DDU, SCEA
Cont…

201. by Melese M. DDU, SCEA
Activity ES EF FF TF
A
B
C
D
E
F
G
H
I
J
K
L
M
N
0
0
0
0
2
2
5
3
3
8
11
9
9
18
0
2
5
3
4
8
11
9
7
10
18
12
11
20
0
0
0
0
4
0
0
0
2
8
0
6
7
0
0
3
0
6
12
3
0
6
9
8
0
6
7
0
Cont…

202. by Melese M. DDU, SCEA
Cont…

203. by Melese M. DDU, SCEA
Cont…

204. by Melese M. DDU, SCEA
Cont…
26
TheaboveFigureshowsthebarchartandtheresourcehistogramof
theprojectandtheweeklyusageoftheresourcesandthetotalusage
of90resourceunits.
Asshownintheresourcehistogram,thepeakresourceusageis13
unitsandtheminimumusageis2units.
Thetotalresourceusageequals90unitswithutilizationperiodof18
weeks.Then,theaverageresourceusageequals5units(=90/18=5).

205. by Melese M. DDU, SCEA
Cont…
27
Theresourcedemandonweeks9,10,and11ishigh,whileitislowin
weeks13through18.
Accordingly,thesolutionprocesswilltrytosifttheresourcesfromthat
peakperiodtotheperiodoflowusage.
Thefollowingactivitieswillbeshifted:
ActivityMhasafreefloatof7weeks.ShiftingactivityMby7weeks
willreducethepeakusageoftheresourceonweeks10and11and
increasetheusageonweeks17and18.Also,shiftingactivityMwill
givechanceforprecedingactivitiestobeshifted.

206. by Melese M. DDU, SCEA
Cont…
28
ActivityJcanbeshiftedby6,howeverithas8weeksfreefloat.
ByshiftingactivityJ,thefreefloatofbothactivitiesEandFarechanged.
ShiftactivityLby2weekstooptimizetheresourceusage.
Thefreefloatofactivitywillbechangedto2weeks.
Next,shiftactivityEby10weekstoimprovetheresourceusage.
ShiftactivityHby2weeks.
Finally,shiftactivityFby1week

207. by Melese M. DDU, SCEA
Cont…

208. by Melese M. DDU, SCEA
Cont…

209. by Melese M. DDU, SCEA
Levelled resource histogram

210. by Melese M. DDU, SCEA
Resource-constrained Scheduling
Shortage of resources is a major challenge for construction projects.
Often, the number of skilled labor is limited, related equipment has
to be returned as soon as possible, and / or a limited require our
special consideration.
Scheduling under these resource constraints becomes a complex
problem, particularly when more than one resource is limited.

211. by Melese M. DDU, SCEA
Resource needed exceed resource limit

212. by Melese M. DDU, SCEA
Cont…
Thetechniquethatdealswithlimitedresourceshasbeenreferredtoas
"resourcescheduling“or"resource-constrainedscheduling”.
Theproblemofresource-constrainedschedulingappearsaftertheinitial
networkanalysisisconductedandabarchartisdrawn.
Aresourceconflictoccurswhenatanypointinthescheduleseveralactivities
areinparallelandthetotalamountofrequiredresource(s)exceedsthe
availabilitylimit,foranyoftheresourcesrequiredintheseparallelactivities.
ThesituationisillustratedintheaboveFigurewithactivitiesA,B,andCthat,at
timeperiod3,require5,while4areonlyavailableperday.

213. by Melese M. DDU, SCEA
Cont…
Thesimplesolutiontothatsituationisthatwecanprioritizingtheparallel
activities,giventheresourcetohigherpriorityactivitiesanddelaytheothers
untiltheearliesttimetheresourcebecomeavailableagain.
Noticethatifwedelayanactivityattimeperiod3,tosolvethesituation,we
mayendupwithanotherresourceconflictlaterintime.
Continuingwithidentifyingnextconflictpointsandresolvingthem,determines
thenewscheduleandthenewprojectduration.
Accordingly,theobjectiveinsuchsituationistodelaysomeactivitiessothatthe
resourceconflictisresolvedandtheprojectdelayisminimized.

214. by Melese M. DDU, SCEA
Resource scheduling using least TF rule

215. by Melese M. DDU, SCEA
heuristic rules
Theseheuristicrulesarebasedmainlyonactivitycharacteristics.
Thetwomosteffectiveandcommonlyusedheuristicrulesaretheleast
total-float(LTF)andtheearliestlate-start(ELS).
Thesetworuleshavebeenproventoprovideidenticalresults,withthe
ELSrulebeingadvantageouscomparedtotheLTFrule.
Assuch,theELSrulecanbeappliedwithmuchlesscomputationaleffort
thantheLTFrule,andaccordinglyhasbeenusedasabasisforthe
resourcescheduling.

216. by Melese M. DDU, SCEA
Procedure
Prepare a complete activity schedule
Aggregate the daily resource demand
If demand greater than available then determine activities compete for
resources
Prioritize these activities based on their LS
Allocate resources to some activities and delay the others
Put your solution in table format

217. by Melese M. DDU, SCEA
Example
Activity Duration
(Weeks)
Predecessors Resource (units/week)
R1≤8 R2≤1
A
B
C
D
E
F
G
H
I
J
K
4
6
2
8
4
10
16
8
6
6
10
-
-
-
A
D
B
B
F
E, H
C
G, J
3
6
4
0
4
0
4
2
4
5
2
0
1
0
1
1
1
0
0
1
1
0
Forthefollowingprojectdeterminetheactivitiesschedulestartandfinishtimes
sothattheweeklyresourceusagedoesnotexceedtheresourcelimits.

218. by Melese M. DDU, SCEA
Cont…

219. by Melese M. DDU, SCEA
Cont…

220. by Melese M. DDU, SCEA
Cont…

221. by Melese M. DDU, SCEA
Final Schedule
Project Completion Time =40 Weeks

222. by Melese M. DDU, SCEA
End of Chapter 6
Construction Resources management
Lecture # 6
Thank You!!!
Construction Management [CENG 5194]

223. Construction Management [CENG 5194]
Civil Engineering Department
By: Melese Mengistu (MSc. Construction Engineering and Management)
Lecturer at Dire Dawa University Institute Of Technology-School Of
Civil Engineering & Architecture
E-mail: [email protected]

224. by Melese M. DDU, SCEA
Construction Management [CENG 5194]
Chapter 7 and 8
Project finance & Contract Cash Flow and
Project control
Lecture # 7 and # 8
2

225. by Melese M. DDU, SCEA
Project finance and Contract Cash Flow
Attheprojectlevel,aproject’scashflowisthedifferencebetweentheproject’s
expenseandincome
Cashflow=Cashin–Cashout=Income-Expense
Forecastingcashflowisnecessaryfor:
Toensurethatsufficientcashisavailabletomeetthedemands.
Itshowsthecontractorthemaximumamountofcashrequiredandwhenitwillbe
required.Thus,thecontractorcanmadearrangementstosecuretherequiredcash.
Itprovidesareliableindicatortolendinginstitutionsthatloansmadecanbe
repaidaccordingtoanagreedprogram.
Itensuresthatcashresourcesarefullyutilizedtothebenefitoftheownerand
investorsinthecompany.

226. by Melese M. DDU, SCEA
Thethreemainingredientsindeterminationofcashfloware:
Expenses(cashout):Itistheaggregateofthepaymentswhichthecontractor
willmakeoveraperiodoftimeforallresourcesusedintheprojectsuchaslabor,
equipment,material,andsubcontractors.
Income(cashin):Itrepresentsthereceiptsacontractorwillreceiveovera
periodoftimefortheworkhe/shehascompleted.
Timingofpayments:incashflowanalysis,weareinterestedinthetimingof
paymentsrelatedtotheworkdonebythecontractor.
Cont…

227. by Melese M. DDU, SCEA
Construction Project Cash out
Thecoststhatspentonaspecificactivityorprojectcanbe
classifiedas;
Fixedcost:coststhatspentonceatspecificpointoftime(e.g.,
thecostofpurchasingequipment,etc.)
Time-relatedcost:costsspentalongtheactivityduration(e.g.,
laborwages,equipmentrentalcosts,etc.)
Quantity-proportionalcost:costschangeswiththequantities
(e.g.,materialcost)

228. by Melese M. DDU, SCEA
The cash flow calculation steps
Performprojectschedule.
Drawbarchartbasedonearlyorlatetimings.
Calculatethecostpertimeperiod.
Calculatethecumulativecost.
Adjustthecostaccordingthemethodofpayingittoproducethe
expenses.
Calculatethecumulativerevenue(revenue=costx(1+markup)).
Adjusttherevenuebasedontheretentionanddelayofownerpayment.
Calculatethecashflow(cashflow=income–expense)atthecontract
differenttimes.

229. by Melese M. DDU, SCEA
Considertheconstructionof8-weekfoundationactivitywithoperationcostof
LE8800.Theoperationcostisbrokendownintothefollowingelements:
LaborLE1600paidweekly,PlantLE4000paidweeklyafter4weeks
creditfacility,MaterialsLE800paidweeklyafter5weekscredit
facility,SubcontractorsLE2400paidweeklyafter3weekscredit
facility.Determinetheexpenses(cashout)ofthisactivity.
Solution
Atime-scaledplanisdevelopedforthisactivityforthepaymentsforlabor,
plant,material,andsubcontractors.Thecotwillbeplottedweeklywiththe
delayspecifiedinExample
Example1

230. by Melese M. DDU, SCEA
Cont…

231. by Melese M. DDU, SCEA
The S-Curve
Thecurverepresentsthecumulativeexpendituresofaprojectdirectandindirect
costsovertimeiscalledtheS-curveasittaketheS-shape.
Inmanycontracts,theownerrequiresthecontractortoprovideanS-curveofhis
estimatedprogressandcostsacrossthelifeoftheproject.
ThisS-shapedofthecurveresultsbecauseearlyintheproject,activitiesare
mobilizingandtheexpenditurecurveisrelativelyflat.
Asmanyotheractivitiescomeon-line,thelevelofexpendituresincreasesandthe
curvehasasteepermiddlesection.
Towardtheendofaproject,activitiesarewindingdownandexpendituresflatten
again.
TheS-Curveisoneofthemostcommonlytechniquestocontroltheprojectcosts.

232. by Melese M. DDU, SCEA
Cont…

233. by Melese M. DDU, SCEA
Example 2
ConsidertheprojectshowninthefollowingFigure.Thecostsofactivitiesare
assumedasshowninThefollowingTable.Theindirectcostsoftasksarecalculated
consideringadailycostofLE500.ItisrequiredtodrawtheS-curveofthetotalcost
oftheproject.

234. by Melese M. DDU, SCEA
Cost data

235. by Melese M. DDU, SCEA
Cont…

236. by Melese M. DDU, SCEA
Project Income (Cash-in)
Theflowofmoneyfromtheownertothecontractorisintheformofprogress
payments,Advancedpaymentandretentionmoney.
Estimatesofworkcompletedaremadebythecontractorsperiodically(usually
monthly),andareverifiedbytheowner'srepresentative.
Dependingonthetypeofcontract(e.g.,lumpsum,unitprice,etc.),theseestimates
arebasedonevaluationsofthepercentageoftotalcontractcompletionoractual
fieldmeasurementsofquantitiesplaced.
Ownersusuallyretain10%ofallvalidatedprogresspaymentwhichisusuallypaid
withthelastpayment.
Whenthecontractorcollectshis/hermoneyitisnamedprojectincome(cashin).

237. by Melese M. DDU, SCEA
The S-Curve for the Example Project
Project revenue and income curves

238. by Melese M. DDU, SCEA
Calculating Contract Cash Flow
Ifweplottedthecontractexpenseandincomecurvesagainsteachother,
thenthecashflowisthedifferencebetweenthepointsofbothcurves.
Thecontractormayrequestanadvancedormobilizationpaymentfromthe
ownerandthepositionoftheincomeprofileisshiftedsothatnooverdraft
occurs.

239. by Melese M. DDU, SCEA
Effect of advanced payment on improving cash flow

240. by Melese M. DDU, SCEA
Example 3
Inthisproject,themarkupequals5%andthecontractorwillpayhisexpensesimmediately.
Retentionis10%andwillbepaidbackwiththelastpayment.Thecalculationswillbemade
every8days,i.e.,thecontractorwillreceivehis/herpaymentevery8-days(timeperiod).
Owner’spaymentisdelayedoneperiod,whilethecontractorwillsubmitthefirstinvoiceafter
thefirstperiod.Noadvancedpaymentisgiventothecontractor.

241. by Melese M. DDU, SCEA
Project cost and revenue

242. by Melese M. DDU, SCEA
Solution
Revenueofeachactivityiscalculatedasrevenue=cost(1+markup)
Bysumminguptheactivitiescostandrevenue,
Totalcost=LE150,000&
Totalrevenue=LE157,500.
Byconsideringthatboththecostandtherevenueareevenlydistributed
overtheactivitiesdurations.
Calculationswillbemadeevery8-daysandprojectdurationisdividedinto
fourperiodseachoneequals8days.
Inaddition,oneperiodisaddedafterprojectcompletionbecauseof
paymentdelayedbyoneperiod(8days)

243. by Melese M. DDU, SCEA
Cont…
Summingupthecostsitbecamedirectexpensestothecontractorasthere
isnodelayinpayingthem.
Theexpectedownerpaymentsarethenaddeduptofromtheproject
revenue.
Theretentionissubtractedfromtheownerpaymentandwillbepaidback
tothecontractorwiththelastpayment.
AsthecontractorreceivesapaymentofLE43,470,thecashflowimproves
andbecomes-54,530(43,470–98,000).

244. by Melese M. DDU, SCEA
Then,therevenueisdelayedbyoneperiodtoformthecontractorincome.
Thecalculationsinthelastrowarethedifferencebetweentheproject
incomeandprojectexpense.
Havingtwovaluesinsomeperiodsshowsthesuddenchangeofthecash
flowasthecontractorreceivesmorepaymentsfromtheowner.
Forexample,inthesecondperiod,justbeforethecontractorreceive
his/herpaymentthecashflowwas(0–98,000=-98,000LE).
Cont…

245. by Melese M. DDU, SCEA
Themaximumoverdraftmoney(maximumcash)isLE98,000andwillbe
neededatthe16thdayoftheproject.
Henceitshowstheimportanceofstudyingthecontractcashflow.
Accordingly,thecontractorcanmadehisarrangementstosecurethe
availabilityofthisfundonthespecifiedtime.
BelowFigureshowsthecontractexpenseandincomecurves.
Thesecurveswillbeneededtocalculatethecontractorcostofborrowing
orinvestmentoftheoverdraftmoney(areabetweenexpenseandincome).
Cont…

246. by Melese M. DDU, SCEA
Cash flow

247. by Melese M. DDU, SCEA
Cash flow

248. by Melese M. DDU, SCEA
Minimizing Contractor Negative Cash Flow
Figure : Expense and income curves

249. by Melese M. DDU, SCEA
Contract net cash flow for example 3

250. by Melese M. DDU, SCEA
Procedures to minimize contractor negative cash flow
Adjustmentofworkscheduletolatestarttiminginordertodelay
paymentsandbeawarethatcompletiontimedelaymighthappenand
maysubjectedtoliquidateddamages.
Reductionofdelaysinreceivingrevenues.
Askingforadvancedormobilizationpayment.
Achievingmaximumproductioninthefieldtoincreasethemonthly
payments.
Adjustthetimingofdeliveryoflargematerialorderstobewiththe
submittalofthemonthlyinvoice.
Delayinpayingequipmentrentals,materialsuppliersandsubcontractors.

251. by Melese M. DDU, SCEA
Cost of Borrowing (Return on Investment)
Cashrequirements(negativecashflows)duringaprojectresultina
contractoreitherhavingtoborrowmoneytomeethis/herobligationor
usingfundsfromthecompanyreserves.
Accordingly,thereshouldbeachargeagainsttheprojectfortheuseof
thesefunds.
Chargeagainsttheprojectistheareabetweentheexpensesandincome
curvesintermsofunitsofLExtimeperiod(moneyxtime)multiplyingby
interestrate.
Cost of borrowing = net area x interest rate

252. by Melese M. DDU, SCEA
Cont…
Notethat,thetimemaybeindays,weeks,months,etc.,theinterest
rateshouldbecalculatedinthesametimeperiodasthetime
periodoftheunitareas.
Forexample,iftheunits’areasarecalculatedinLE.month,thenthe
interestrateshouldbeinmonths.

253. by Melese M. DDU, SCEA
Example 3
Considertheaboveexample,itisrequiredtocalculatethecostofborrowing
iftheinterestrateis1%everytimeperiod(8-days).
Solution
Referringtoexpensesandincomecurves,theapproximatenumberofunit
areasbetweentheexpenseandtheincomecurvesequals24units.
EachunitequalsLE10,000timeperiod.
Then,thecostofborrowing=24x10,000x0.01=LE2400.
Thisvaluemustbeaddedtothecontractprice.

254. by Melese M. DDU, SCEA
Project Cash Flow
Theprojectcashflowdealswiththewholelifeoftheprojectnottheconstruction
periodonly.
projectcashflowstudiestheprojectfinancefromthefeasibilitystudiesphasetill
theoperationphase.
Inthiscase,thetimeismuchlongerthanthatofthecontract.
Attheearlystageofaproject,theprojectexperiencenegativecashflowas
thereisnoincome.
Intheoperationstage,therevenuewillincreasethantheexpenses.
Whencomparingtheeconomicsofprojects,thecumulativecashflowprovides
indicatorsforsuchcomparisonaspaybackperiod,profit,andthemaximum
capital.

255. by Melese M. DDU, SCEA
Typical project cash flow

256. by Melese M. DDU, SCEA
Project Profitability Indicators
Profit:Itisthedifferencebetweentotalpaymentsandtotalrevenuewithoutthe
effectoftimeonthevalueofmoney,theprojectwiththemaximumprofitis
rankedthebest.
Maximumcapital:Itisthemaximumdemandofmoney,i.e.,thesummationofall
negativecash(expenditures)andTheprojectwithminimumcapitalrequiredis
rankedthebest.
Paybackperiod:Itisthelengthoftimethatittakesforacapitalbudgeting
projecttorecoveritsinitialcost,wherethesummationofbothcashoutandcashin
equalszero.
Whencomparingalternatives,theprojectwiththeshortestpaybackperiodis
rankedthebest.

257. by Melese M. DDU, SCEA
Example 4
TwoprojectsAandBhaveannualnetcashflowsasshowinbelowTable.Assumeall
cashflowsoccurattheyear-end.Establishtherankingoftheprojectsinorderof
attractivenesstothecompanyusing:
a)Maximumcapitalneeded
b)Profit
c)Paybackperiod

258. by Melese M. DDU, SCEA
Solution
Cont…
Cumulative cash flow

259. by Melese M. DDU, SCEA
Maximumcapital:projectA(LE80,000)isbetterthanprojectB(LE110,000)
becauseitneedslesscapital.
Profit:ProjectB(LE80,000)ismoreprofitablethanprojectA(LE65,000).
Paybackperiod:ProjectA(5years)isbetterthanprojectB(6years)becauseis
hasshorterpaybackperiod.
Cont…

260. by Melese M. DDU, SCEA
Project Control
Lecture # 8

261. by Melese M. DDU, SCEA
Project Control
Duringtheactualconstruction,changesarelikelytodelaytheprojectand
leadtoinordinatecostincreases.
Asaresult,thefocusofprojectcontrolisonfulfillingtheoriginaldesign
plansorindicatingdeviationsfromtheseplans,ratherthanonsearching
forsignificantimprovementsandcostsavings.
Inconstruction,noproject,almost,isexecutedasplanned.
Controlneedstobecarriedoutduetothedynamicnatureofthe
constructionprocess.
Controllingafterprojectfinishistrivial/unimportantandupdatesare
usuallydoneperiodically.

262. by Melese M. DDU, SCEA
Thecauseofdelays/costoverruns:
Changeinactivitydurationsandquantities.
Suddenchangesoftheavailabilityofresources.
Changeorders.
Paymentdelay
Dispute
Accidents.
Procurementdelaysand
Cont…

263. by Melese M. DDU, SCEA
Schedule Updating
A procedure for manual schedule updating.
Changethedurationofallcompletedactivitiestozero.
IdentifyallactivitiesonwhichworkiscurrentlyprocessingasLive
Activities
Putearlystarttimeofliveactivitiesequalstheupdatingdateand
theirdurationsequalremainingduration.
Changedurationoffutureactivitiesasgivenintheupdatereport.
Carry-outnetworkanalysisinthenormalwayandprepareanew
activityschedule.

264. by Melese M. DDU, SCEA
Example

265. by Melese M. DDU, SCEA
At the end of the 7th week, new filed data are collected and the project
status activities is as follows:
Activities A, B, D, and E have been completed.
Remaining Duration of activity C is one week.
Remaining Duration of activity H is 4 weeks.
Activity G will not start until beginning of week 10.
Overlap between activities K and G is one week only
Volume of work of activity L has been increased by 33%.
Activity J has been omitted.
Cont…

266. by Melese M. DDU, SCEA
Scheduling data

267. by Melese M. DDU, SCEA
Theupdatedprecedencenetworkandthecorrespondingupdated
scheduleareshownintheaboveFigure.
Itisshownthatanewcriticalpathisdeveloped.Thenewproject
completiontimeis21weekswhichindicatesthatadelayofoneweekis
encountered.
Correctiveactionsshouldbetakentoimproveprojectperformanceduring
theremainingportion.
Cont…

268. by Melese M. DDU, SCEA
Updated network

269. by Melese M. DDU, SCEA
Delays Analysis
Workchangesmeanchangesinthevolumeanddurationofworktobe
performedfromthatenvisagedatthestartofthecontract.
Variationintheformofadditionanddeductionresultinmoreorless
costandtimetoexecutethevarieditem.
Ontheotherhand,omissionsmeanlesscostbutnotnecessarilyless
time.
Itmightresultinwastingresources.
Forinstance,ifthequantityofworkinacriticalactivityisincreasedby
x%thenthedurationoftheactivitywillbeextendedbyx%.

270. by Melese M. DDU, SCEA
Cont…
The direct cost of the activity should be increased by the same ratio
while the indirect cost of the contract might be increased for the
extended period
Itistypicalforconstructioncontractstobedelayed.
Adelaythatoccurredonanoncriticalactivitydoesnotparticipate
tothedelayingcompletiondateofthecontract.
Therefore,delaysonnon-criticalpathsarenotconsidered

271. by Melese M. DDU, SCEA
Compensabledelays:Thoseoverwhichtheclienthascontrol:
Non-excusabledelays:Thoseoverwhichthecontractorhascontrol
Excusabledelays:Thoseoverwhichtheneitherpartyhasanycontrol;;
and
Concurrent delays:two or more delays that occur at the same time,
either of which, if it occurred alone, would have affected contract
completion date.
Types of Delays

272. by Melese M. DDU, SCEA
Compensable delays
Adelayisdeemedcompensabletothecontractorwhenit’swithinthecontrolof,is
thefaultof,orisduetothenegligenceoftheclient.
Examplesinclude:
•latepossessionofsite;andfaultydesign;
•incompletedrawingsandspecification;
•changesinscopeandsuspensionofwork;
•differingsiteconditions;latedeliveryofclient-suppliedmaterials;and
•client’sfailuretodiscloseinformationvitaltothecontractor.
Forthistypeofdelays,theconditionsofcontractshouldallowthecontractortobe
entitledtoatimeextensionandtomonetaryrecompenseforextracosts
associatedwiththedelay.

273. by Melese M. DDU, SCEA
Inthiscategory,thecontractor’sownactionsorinactionshavecaused
thedelay.
Thecontractorisentitledneithertimeextensionsnormonetary
recompensefromtheclient.
He/shemaypayliquidateddamagesaccordingtothecontract.
Non-excusable delays

274. by Melese M. DDU, SCEA
Excusable delays
Theseareoccurrencesoverwhichneithertheclientnorthecontractorhas
anycontrol.
Exampleincludes:
Unforeseenfutureeventswhichthecontractorhasnotbeenaware;
Impracticablethingswhichthecontractorcanonlydoatanexcessive
cost;
Eventsinwhichthecontractorisblameless,suchasmaterialshortage
beyondwhatwasexpectedatthetimeofbidding.
Thecontractorshoulddeclaretheexcusabledelays.
Thesolereliefforthesedelaysisatimeextension.

275. by Melese M. DDU, SCEA
Concurrent delays
Concurrentdelaysaretwoormoredelaysthatoccuratthesametime.
They can be classified as follows:
Excusable delays and non-excusable delays;
Excusable delays and compensable delays;
Excusable delays and compensable delays and non-excusable delays; and
Compensable delays and non-excusable delays.
Concurrentdelayswithanexcusabledelaywillgenerallybeconsideredas
excusabledelays.

276. by Melese M. DDU, SCEA
Cont…
Forthesedelays,thecontractorisentitledtotimeextensionifthedelays
areonthecriticalpath.
Thisprotectshimfromanyresultingliquidateddamages.
Forconcurrentcompensableandnon-excusabledelays,thecontractoris
allowedatimeextensionforcompletionwitheachpartysufferinghis/her
ownlosses.
Thetermsofthecontractshoulddeclarethemethodofevaluationofsuch
claims.

277. by Melese M. DDU, SCEA
End of Chapter 7 and 8
Project finance & Contract Cash Flow and
Project control
Lecture # 7 and # 8
Thank You!!!
Construction Management [CENG 5194]

278. Construction Management [CENG 5194]
Civil Engineering Department
By: Melese Mengistu (MSc. Construction Engineering and Management)
Lecturer at Dire Dawa University Institute Of Technology-School Of
Civil Engineering & Architecture
E-mail: [email protected]

279. by Melese M. DDU, SCEA
Construction Management [CENG 5194]
Chapter 9
Construction Safety and Insurance
Lecture # 9
2

280. by Melese M. DDU, SCEA
Major hazards of construction
Falls
Electric-shock
Being struck by
falling objects
Confined during
excavation

281. by Melese M. DDU, SCEA
Fall Protection
This section will discuss:
Conditions that required use of fall protection
Options available to protect workers

282. by Melese M. DDU, SCEA
Fall Protection
Falls are the leading cause of fatalities in the
construction industry
Conditions that required use of fall protection
A fall from as little as 4-6 feet
Can cause loss of work
In some cases death

283. by Melese M. DDU, SCEA
When fall protection is needed?
Walkways &
ramps
Open sides &
edges
Holes
Concrete forms &
rebar
Excavations
Roofs
Wall openings
Bricklaying
Residential
Construction

284. by Melese M. DDU, SCEA
Safety Nets
Hand Rails
Safety Harness
(PFAS)
Equipment guards
Fall protection systems
must be in place
before work start
Fall protection and prevention
options

285. by Melese M. DDU, SCEA
Must be properly
trained
Key requirements
No free fall more
than 6 feet
Must be inspected
prior to use
Safety line must be
able to support 5000
lbs
Personal Fall Arrest System, PFAS

286. by Melese M. DDU, SCEA
Guardrails
Top rail between 39
to 45 inches tall
Toeboards at least
3 inches tall
Top rail
Mid Rail
Toe board

287. by Melese M. DDU, SCEA
Safety Nets
Used to catch
falling workers
Placed not more
than 30 FT below
work area
Placed not more
than 8-13 ft from
edge of working
area

288. by Melese M. DDU, SCEA
Falling Objects
Hardhats are required
Use of canopies is
authorized
Barricade the area to
prevent unauthorized
entry

289. by Melese M. DDU, SCEA
SUMMARY
A fall of 6 ftor more protection is needed
Use fall protection on:
Walkways, ramps, open sides, edges, excavations,

290. by Melese M. DDU, SCEA
Electrical Safety
This section will discuss:
Safety requirement
Hazard prevention and control
Most common injuries
Personal Protective Equipment

291. by Melese M. DDU, SCEA
How it works
Electricity is the flow of
energy from one place
to another
Requires a source of
power (generating
station, power station or
portable generator)
Travels in a close circuit

292. by Melese M. DDU, SCEA
Electrical Safety
Always assume that all overhead wires are energized
Never touch a down power line
Never operate electrical equipment while standing in
water
Coming in contact with an electrical voltage can cause
current to flow through the body, resulting in electrical
shock and burns. Serious injury or even deathmay occur.

293. by Melese M. DDU, SCEA
ELECTRICAL ACCIDENTS
Most Frequent Causes
Contact with Power Lines
Lack of Ground Fault Protector
Missing Ground on electric cords
Improper use of equipment
Improper use of electric cords

294. by Melese M. DDU, SCEA
Electrical Hazards
•Electrical accidents are caused by a combination
of three factors:
•Unsafe equipment and/or installation,
•Workplaces made unsafe by the environment,
and
•Unsafe work practices

295. by Melese M. DDU, SCEA
Hazard: Exposed electrical parts
Isolate electrical parts
Use guards or barriers
Replace covers

296. by Melese M. DDU, SCEA
HAZARD:Conductorsentering boxes
Shall be protected
from abrasion
All openings shall be
closed to prevent
access

297. by Melese M. DDU, SCEA
HAZARD:
Overhead Power Lines
Usually not insulated
Carry extremely high voltage
80% of all lineman deaths were caused by contacting
a live wire with a bare hand.

298. by Melese M. DDU, SCEA
HAZARD:
Overhead Power Lines (Cont)
Equipment that could
contact power lines:
Cranes
Scaffolds
Ladders
Scissor lift

299. by Melese M. DDU, SCEA
MOST COMMON INJURIES
DIRECT
Electrocution or death
Shock
Burns
INDIRECT
Falls

300. by Melese M. DDU, SCEA
Most Common injuries
Electric shock/Electrocution
Electric shock is received when electrical current
passes through the body.
Can cause severe damage or death.
You will get an electrical shock if a part of your
body completes an electrical circuit by…
Touching a live wire and an electrical ground,
Touching a live wire and another wire at a
different voltage.

301. by Melese M. DDU, SCEA
Most Common injuries:
Burns
Most common shock-related injury
*Electrical Burns, Arc or Flash Burns,
Thermal Burns
Occurs when you touch electrical wiring
or equipment that is improperly used or
maintained
Very serious injury that needs Immediate
attention

302. by Melese M. DDU, SCEA
Most Common injuries
Falls
Caused by involuntary electric shock
Occurs on personnel working in
elevated locations (ladder,
scaffolds, etc)
May result in serious injury or death

303. by Melese M. DDU, SCEA
PERSONAL PROTECTIVE: EQUIPMENT
PPE should always be first line
of defense
Rubber gloves
Rubber Insulated work boots,
Hoods, sleeves or blankets

304. by Melese M. DDU, SCEA
SAFETY WORK PRACTICES
Only qualify person should work on electrical
equipment
Use special insulated tools when working on fuses
with energized terminals
Don’t use worn or frayed cords and cables
Don’t fasten extension cords with staples, hang
from nails, or suspend by wire.

305. by Melese M. DDU, SCEA
SAFETY WORK PRACTICES
De-energize live parts before commencing
work
Lock or Tag out circuits (or both)
Inspect extension cords
Avoid contact with overhead lines
Avoid wet conditions
Check switches and insulation

306. by Melese M. DDU, SCEA
SUMMARY
Electrical equipment must be:
Listed and labeled
Free from hazards
Used in the proper manner
If you use electrical tools you must be:
Protected from electrical shock
Provided necessary safety equipment

307. by Melese M. DDU, SCEA30
Are You Working On A Trench Or Digging Your Grave?

308. by Melese M. DDU, SCEA
TRENCHING & EXCAVATION
HAZARDS
Risks of excavation
How to protect employees from cave-ins
Factors that pose a hazard to employees
working in excavation
Role of competent person

309. by Melese M. DDU, SCEA
EXCAVATION HAZARDS
Risks
Most hazardous construction operation
Cave-ins are the greatest risk
Most accidents occurred in
5-15 ft deep

310. by Melese M. DDU, SCEA
EXCAVATION HAZARDS
Employee Protection
Employees should be protected from caves-in by
using a well designed protective system
Systems must be able to support expected loads to
the system

311. by Melese M. DDU, SCEA
EXCAVATION HAZARDS
Protective System Design
A well designed system will have a correct design of
sloping and benching systems
Correct design of support systems
Handle materials and equipment

312. by Melese M. DDU, SCEA
EXCAVATION HAZARDS
Employee Protection
Protect employees from potential
cave-ins
Slope or bench sides of excavation
Place shields between the side
of the excavation and work area

313. by Melese M. DDU, SCEA
Inadequate Worker Protection

314. by Melese M. DDU, SCEA
Factors that pose hazards to
employees
Soil classification
Depth of cut
Water content of soil
Changes due to weather and climate
Other operations in the vicinity

315. by Melese M. DDU, SCEA
38
Types of Protection
Trench Shield
A trench shield was
built around this work
area

316. by Melese M. DDU, SCEA
39
Hydraulic Jacks
Hydraulic Jacks
Easily dropped in
place and adjusted
Trench pins installed
in case of hydraulic
failure

317. by Melese M. DDU, SCEA
40
Egress Systems
A stairway, ladder, or
ramp must be present
in excavations that are
4 or more feet deep,
and within 25 feet of
the employees
Must extend 3FT
above excavation
This ladder does not meet the
requirements of the standard

318. by Melese M. DDU, SCEA
EXCAVATION HAZARDS Competent Person
•Must have had specific training in and be
knowledgeable about:
•Soils classification
•The use of protective systems
•The requirements of the standard
•Must be capable of identifying hazards, and
authorized to immediately eliminate hazards

319. by Melese M. DDU, SCEA
EXCAVATION HAZARDS
Competent Person
•A competent person must make daily inspections of
excavations, areas around them and protective systems:
•Before work starts and as needed
•After rainstorms, high winds or other occurrence which
may increase hazards
•When you can reasonably anticipate an employee will
be exposed to hazards.

320. by Melese M. DDU, SCEA
SUMMARY
•The greatest risk in an excavation is a cave-in.
•Employees can be protected through sloping, shielding,
and shoring the excavation.
•A competent person is responsible to inspect the
excavation.
•Other excavation hazards include water accumulation,
oxygen deficiency, toxic fumes, falls, and mobile
equipment

321. PERSONAL PROTECTIVE EQUIPMENT
IN THE CONSTRUCTION INDUSTRY
29 CFR 1926.95-106

322. by Melese M. DDU, SCEA
What is PPE?
Equipment that creates a barrier against workplace
hazards
Examples include hard hats, goggles, gloves, hearing
protection, etc.
A temporary measure

323. by Melese M. DDU, SCEA
Personal protective equipment
The employer is responsible for requiring wear of
appropriate personal protective equipment in all
operations where there is exposure to hazardous
conditions…
1926.28(a)
General Safety and Health
Provisions

324. by Melese M. DDU, SCEA
Personal protective equipment
Regulations governing the use, selection, and maintenance
of personal protective and lifesaving equipment are
described under subpart E of this part.
General Safety and Health
Provisions

325. by Melese M. DDU, SCEA
Criteria for PPE
Protective equipment, including PPE for eyes, face, head
and extremities etc. … shall be provided, used, and
maintained in a sanitary condition and reliable
condition.

326. by Melese M. DDU, SCEA
Criteria for PPE
Employee-owned equipment
Where employees provide their own protective equipment,
the employer shall be responsible to assure its adequacy,
including proper maintenance, and sanitation of such
equipment.
1926.95(b)

327. by Melese M. DDU, SCEA
Criteria for PPE
Design
All personal protective equipment shall be of safe design
and construction for work to be performed.
1926.95(c)

328. by Melese M. DDU, SCEA
Training
Employer shall instruct each employee in the recognition
and avoidance of unsafe conditions and the regulations
applicable to his work environment to control or
eliminate any hazards or other exposure to illness or
injury.
1926.21(b)

329. by Melese M. DDU, SCEA
Basic Hazard Categories
Impact
Penetration
Compression
Chemical
Heat
Harmful dust
Light radiation
Falls

330. by Melese M. DDU, SCEA
Hazard Sources
Motion
Temperature
Chemical exposure
Light radiation
Elevation
Sharp objects
Rolling/pinching
Electrical hazards
Workplace layout
Worker Location

331. by Melese M. DDU, SCEA
Employer Requirements
Conduct hazard assessment
Insure adequacy of PPE
Provide employee training
Maintain written certification

332. by Melese M. DDU, SCEA
Head Protection
Employees working in areas where there is a possible
danger of head injury from impact, or from falling or
flying objects, or from electrical shock and burns, shall
be protected by helmets.
1926.100(a)

333. by Melese M. DDU, SCEA
Head Protection
Helmets for the protection of employees against impact and
penetration of falling and flying object shall meet the
specification contained in American National Standard Institute
(ANSI), Z89.1-1969, Safety Requirements for Industrial Head
Protection.
1926.100(b)

334. by Melese M. DDU, SCEA
Head Protection
Helmets for the protection of employees exposed to
high voltage electrical shock and burns shall meet the
specifications contained in American National
Standards Institute (ANSI), Z89.2-1971.
1926.100(c)

335. by Melese M. DDU, SCEA
Hearing Protection
Wherever it is not feasible to reduce the noise levels or
duration of exposure to those specified in Table D-2,
Permissible Noise Exposures, in 1926.52, ear protection
devices shall be provided and used.
1926.101(a)

336. by Melese M. DDU, SCEA
Hearing Protection
Ear protection devices inserted in the ear shall be fitted
or determined individually by competent persons.
Plain cotton is not an acceptable protective device.
1926.101(b)-(c)

337. by Melese M. DDU, SCEA
Eye and Face Protection
Employees shall be provided with eye and face
protection equipment when machines or operations
present potential eye or face injury from physical,
chemical, or radiation agents.
1926.102(a)(1)

338. by Melese M. DDU, SCEA
Eye and Face Protection
Eye and face protection equipment required by this
Part shall meet the requirements specified in American
National Standards Institute (ANSI), Z89.1-1968,
Practice for Occupational and Education Eye and Face
Protection.
1926.102(a)(2)

339. by Melese M. DDU, SCEA
Eye and Face Protection
Employees whose vision requires the use of
corrective lenses in spectacles, when required by
this regulation to wear eye protection, shall be
protected by goggles or spectacles.
1926.102(a)(3)

340. by Melese M. DDU, SCEA
Eye and Face Protection
Spectacles whose protective lenses provide optical
correction
Goggles that can be worn over corrective spectacles
without disturbing the adjustment of the spectacles
Goggles that incorporate
corrective lenses mounted
behind the protective lenses
1926.102(a)(3)

341. by Melese M. DDU, SCEA
Foot Protection
Safety-toe footwear for employees shall meet the
requirements and specifications in American National
Standard for Men’s Safety-Toe Footwear, Z41.1-1967.
1926.96

342. by Melese M. DDU, SCEA
Respiratory Protection
Identical to 29 CFR 1910.134
Written program
Medical evaluation
Fit testing
Selection and use
Maintenance and care
Training
Program evaluation
Recordkeeping
1926.103

343. by Melese M. DDU, SCEA
Safety Belts, Lifelines, Lanyards
Lifelines, safety belts, and
lanyards shall be used only
for employee
safeguarding.
1926.104(a)

344. by Melese M. DDU, SCEA
Safety Belts, Lifelines, Lanyards
Lifelines shall be secured
above the point of operation
to an anchorage or structural
member capable of
supporting a minimum dead
weight of 5,400 pounds.
1926.104(b)

345. by Melese M. DDU, SCEA
Safety Belts, Lifelines, Lanyards
Lifelines used on rock scaling operations, or in areas where the
lifeline may be subjected to cutting or abrasion, shall be a
minimum of ⅞inch wire core manila rope.
For all other lifeline applications, a
minimum of ¾-inch manila or
equivalent, with a minimum breaking
strength of 5,400 pounds, shall be
used.
1926.104(c)

346. by Melese M. DDU, SCEA
Safety Belts, Lifelines, Lanyards
Safety belts lanyard shall be
a minimum of ½-inch nylon, or
equivalent, with a maximum
length to provide for a fall of
no greater than 6 feet.
The rope shall have a nominal
breaking strength of 5,400
pounds.
1926.104(d)

347. by Melese M. DDU, SCEA
Safety Belts, Lifelines, Lanyards
All safety belt and lanyard
hardware shall be drop forged or
pressed steel, cadmium plated in
accordance with Type 1, Class B
plating specified in Federal
Specification QQ-P-416.
Surface shall be smooth and free of
sharp edges.
1926.104(e)

348. by Melese M. DDU, SCEA
Safety Belts, Lifelines, Lanyards
All safety belts and lanyard hardware, except
rivets, shall be capable of withstanding a tensile
loading of 4,000 pounds without cracking,
breaking, or taking a permanent deformation.
1926.104(f)

349. by Melese M. DDU, SCEA
Working Over or Near Water
Life jacket or buoyant work vests must be U.S. Coast
Guard approved.
Prior to and after each use, the buoyant work vests or
life preservers shall be inspected for defects.
Ring buoys shall be provided for rescue operations.
Lifesaving skiff shall be immediately
available.
1926.106(a)-(d)

350. by Melese M. DDU, SCEA
73

351. by Melese M. DDU, SCEA
Construction insurance
74
Constructioninsuranceencompassesallcontractsofindemnitywithinthe
activitiesoftheconstructionindustrywhereinsuranceischosenasthe
mediumthroughwhichliabilitiesareshifted.

352. by Melese M. DDU, SCEA
End of Chapter 7 and 8
Construction Safety and Insurance
Lecture # 9
Thank You!!!
Construction Management [CENG 5194]

353. Construction Management [CENG 5194]
Civil Engineering Department
By: Melese Mengistu (MSc. Construction Engineering and Management)
Lecturer at Dire Dawa University Institute Of Technology-School Of
Civil Engineering & Architecture
E-mail: [email protected]

354. by Melese M. DDU, SCEA
Construction Management [CENG 5194]
Chapter 9
Construction Site Layout Planning and
Preparation of terms of reference
Lecture # 9
2

355. by Melese M. DDU, SCEA
Introduction
3
Constructionsitelayoutinvolvesidentifying,sizing,andplacingtemporary
facilities(TFs)withintheboundariesofconstructionsite.
Thesetemporaryfacilitiesrangefromsimplelay-downareasto
warehouses,fabricationshops,maintenanceshops,batchplant,and
residencefacilities.Requiredtemporaryfacilitiesandtheirareasare
dependinginmanyfactorsincludingprojecttype,scale,design,location,
andorganizationofconstructionwork.

356. by Melese M. DDU, SCEA
4
Mostconstructionsitesthatrunintotroubledosoforreasonsrelatedto
managerialfactorsratherthanbecauseoftechnicalproblems.
Thesite-basedmanagementcanmakesignificantimprovementsinthecost
andtimesavingsduringtheconstructionprocesswithoutinvolvingamass
ofadditionalwork.
Sitemanagementinvolvesmanytasks,suchas:-
siteinvestigationbeforeconstructionprocessstarts,
materialdeliveryandprocurementmanagement,

357. by Melese M. DDU, SCEA
5
keepingbettersiterecords,
keepinggoodsitecommunicationandhighlevelofinformationflow,
monitoringperformanceregularly,
establishingawellco-ordinationsystemamongdifferentparts,and
performingagoodsitelayoutplanning.
Extensivetimelossandcostoverrunscouldresultinlargeprojects,where
thenumberofmanpower,subcontractors,andequipmentinvolvedare
high,ifthereisnoeffectiveandsystematicapproachtositeplanning.

358. by Melese M. DDU, SCEA
6
Adetailedplanningofthesitelayoutandlocationoftemporaryfacilities
canenablethemanagementtomakeconsiderableimprovementby
minimizingtraveltime,waitingtime,andincreasingworkermoraleby
showingbetterandsaferworkenvironment.
Duetoitsimportance,thischapterfocusesonthesitelayoutplanning
problem.

359. by Melese M. DDU, SCEA
7
Theproblemofsitelayoutplanninghasbeensolvedbyresearchersusing
twodistinctlytechniques:optimizationandheuristics.
Mathematicaloptimizationprocedureshavebeendesignedtoproduce
theoptimumsolutions.
Theheuristicmethods,ontheotherhand,usedtoproducegoodbutnot
optimalsolutions.
However,thefirstcategorycannotbeadoptedforlargeprojects,and
thesecondcategoryistheonlyavailablemeanforsolvingthecomplex
reallifeprojects.

360. by Melese M. DDU, SCEA
Problems of Failure to plan the site layout
8
Material
Materials arriving on site should be loaded to be the correct location ant it will
cause double or triple handling of materials to another location. For example:
Stocked over a drainage line or near the edge of excavation;
Too far from the work area;
Too remote from the hoist or not within the radius of the crane;
Obstruct the smooth flow of work traffic across the site;
Wrongly delivered on site and are not needed until much later in the project;
breakable.

361. by Melese M. DDU, SCEA
9
Plant and equipment wrongly located
For example:
Themixerisinaccessibleforthedeliveryofmaterials;
notenoughroomforthestorageofaggregates;
Fixedcranesareunabletoreachallpartsoftheworks;
Hoistshaveinsufficientcapacityorheighttohandletheloadsorbadly
locatedinrelationtothefloorlayout;

362. by Melese M. DDU, SCEA
10
Inadequate space allowed.
Whereinadequatespaceisallowedforthestackingofmaterialsor
activities:
Materialsmaybestackedtohighorstackedonroadwayscausing
hazards.
Workingareasmaybecometoocrampedoradditionalareasmayhave
obeallocatedwiththeconsequentwasteoftimecausedbyhavingto
travelbetweenthem

363. by Melese M. DDU, SCEA
11
Sitehutswronglylocatedinrelationtotheireffectiveuse,suchas:
-Siteofficelocatedtoonearnoisyactivitiessuchasmixer,or
locatedtooneartositeroadsindustyconditions,or
tooremotewithinsufficientoverviewofthesite.
Warehouseshavinginadequateaccessforloadingandunloadingor
locatedininsecurearea.
beforemovingontoasite,itisnecessarytoprepareadetailedsiteplan,
showingthepositionstobetakenbyeveryitemofequipment,
accommodation,ancillaryworkareasandmaterialsstorageareas.

364. by Melese M. DDU, SCEA
Site Layout Planning Elements
12
Safety
Fire prevention: Fire is a major cause of damage on construction sites.
So that, fire extinguishers are basic requirements on a construction project.
Medical services: On construction project a first aid kit is a must.
In remote projects a well-equipped medical room with a doctor and nurse
is important.
Construction safety clothing: Basic safety supplies like safety shoes, hard
hats, gloves, and goggles must be used by workers.

365. by Melese M. DDU, SCEA
13
Site Accessibility
Easy accessibility will keep the morale of the equipment and vehicle
drivers high, minimize the chance of accidents, and save time in
maneuvering to arrive at and leave the project.
In case of large projects, proper planning is required to layout the roads
leading from the nearest highway.
Internal roads are necessary for easy flow of work.
Also, Parking Lots are provided for the owner, office, and craft personnel,
but this facility must be planned where space does exist.

366. by Melese M. DDU, SCEA
14
InformationSigns
Sitemap:Itshouldlocatedetailsoftheproject,anddisplayedinthe
officeofthesitesuperintendentorprojectmanagerandpostedatthe
entrancegate.
Trafficregulatorysigns:Forlargeprojects,trafficregulatorysignshelpin
guidingthetrafficonthesiteandavoidaccidentstoaconsiderable
extent.
Displayoflaborrelations’policyandsafetyrules:Thiswillhelpin
eliminatingdisputesbetweenlaborandmanagement.
Emergencyroutesandundergroundservices:Itisimportanttodisplaythe
emergencyescaperoutesoneveryfloorasthebuildingprogresses.
Locationsofundergroundservicesshouldbemarkedtopreventits
damage.

367. by Melese M. DDU, SCEA
15
Security
Entrance:Itisnecessarytohaveaproperguardentrancetothesite
providedbyabooth.Also,itisnecessarytokeeptrackofallvisitorsto
theproject.
Lighting:Itisnecessarytohaveastandbygeneratortomaintainsite
lighting.
-Fencing:Theboundaryshouldbefencedofffromasecuritypointof
view

368. by Melese M. DDU, SCEA
16
Accommodation
Onlargeconstructionprojects,itisnecessarytoprovidecamp
accommodationforalltypeofstaffinvolvedintheproject.
Offices
Theofficesshouldbeclosetogether,closetothesite,andinasafearea.
Also,providetheofficeswithproperofficeequipment.
Theofficesatthesitemayincludejoboffice,generalcontractoroffice,
andsub-contractorsandconsultantsOffices.

369. by Melese M. DDU, SCEA
17
Water Supply and Sanitation
It is necessary to have water and toilet facilities in convenient locations to
accommodate the work force.
Material Handling
One third or more of all construction operations can be classified as
material handling.
The use of proper equipment for material handling and advance
planning for minimizing multiple handling will result in direct cost and time
savings.

370. by Melese M. DDU, SCEA
18
Storage and site cleaning
It is necessary to plan and reserve storage areas for materials so that
multiple movement of material is avoided.
Laydown areas: Areas reserved for storage of large materials and
equipment and it can be short-term or long-term.
-Warehouses: They are sheltered storage facilities where materials are
stored until they have disbursed to the job.
-Material staging areas: They used when materials are stored near the
work on a short-term basis. They are generally as close to work as
possible.
-Site cleaning: It is necessary at a work place and especially where the
extent of debris produced is high. Regular disposal of debris is necessary

371. by Melese M. DDU, SCEA
19
CraftChange-Houses
Craftchange-housesprovideshelteredspaceforcraftpersonnelto
changeandstoreclothes,wash,andrestduringwaitingperiods.
BatchplantandFabricationShops
Batchplantsareprovidedonprojectswhereitismoreeconomicalto
produceconcreteonsitethantobuyareadymix.
Aggregatestoragepiles,cementsilosandadmixturetankswill
accompanyanon-sitebatchplant.
Shopsareusedwherematerialsandequipmentarefabricatedonsite.
Thisincludeselectrical,mechanical,carpentry,andpaintshops.Also,
testingshopsusedtohousethenecessarytestingequipmentandpersonnel
fortheproject.

372. by Melese M. DDU, SCEA
Temporary Facilities Characteristics
20
Satisfying environmental and safety regulations:
All temporary facilities should satisfy environmental and safety regulations.
Special attention should be paid to temporary facilities like batch plants,
which have high pollution potential. Planners have to make proper
arrangements to control the air, water, and noise pollution from such facilities.

373. by Melese M. DDU, SCEA
21
Availability of diverse solutions for the same problem:
There are many arrangements that can be made to establish a temporary
facility. For example, if a warehouse is required, the planner can build a
warehouse on the site, use existing facilities on the site, rent a building near
the site, or plan a just in time delivery. Based on the usage of the
warehouses, each alternative can be further divided into several sub items.
For example, the material of building the facility can vary from wood, bricks,
to a steel structure.

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Relatively short life span of a specific location:
The life span of temporary facility depends on the duration of the
project. In general, it must be removed as soon as the project is
completed.
Reutilization with a minimum loss for the same or modified function at another
location: Due to the shorter life span of temporary facility on site, planners
consider reutilization of the temporary facilities. This can result in saving the
cost of construction.
With appropriate modifications, most of the temporary facilities can be
used for more different purposes. Therefore, good maintenance, and
storage of the building materials can increase the frequency of
reutilization and decrease construction costs significantly

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Easy of assembly, dismantling, and exploitation: temporary facilities
structures which are easy to assemble and dismantle will reduce both
assembly and disassembly time. As mentioned above, temporary facilities
will need to be removed in a very short period of time after project
completion. Thus, temporary facilities structures should be easy to
assemble and dismantle without any damage to the structure components.
Prefabricated modules are ideal for constructing temporary facilities and
they are usually easy to assemble and dismantle.

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Standardization of design: Standardization of design and construction of
temporary facilities can increase the frequency of reutilization and
reduce the work-hours and cost required for construction the facilities. This
approach makes the maintenance, transportation and storage of
temporary facilities easy. The benefits of the learning curve can be
gained from repetitive field operations, which results in increase of
productivity and quality. Also, benefits are obtained by providing grater
interchangeability of spare parts and reducing the variety of spare parts
stored in the warehouse.

377. by Melese M. DDU, SCEA
Temporary Facilities Selection
25
Construction type: The construction of an industrial plant, such as power
plant, requires more storage and fabrication area for process mechanical
and electrical work than other projects such as a highway project.
Type of contract: For turn-key contract, the contractor can consolidate the
administrative and construction operations, means that fewer but larger
and more efficient temporary facilities can be selected. On the other
hand, if the project is managed under a series of different contracts, this
will translate into a higher number of smaller temporary facilities serving
each individual contractor.

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Project size: A relatively small project can be managed from a trailer or
portable structure. While a five to ten year project may need temporary
facilities of a more permanent nature.
-Project location: Projects located in uninhabited regions or in places
where skilled labor is scarce require additional facilities for eating and
living. Project far from industrial centers require more on site services such
as batch plant, equipment maintenance shops, long term storage area,
and even some other recreational centers for the families.

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380. by Melese M. DDU, SCEA
End of Chapter 9
Construction Site Layout Planning and
Preparation of terms of reference
Lecture #
Thank You!!!
Construction Management [CENG 5194]