Introducing the
Relationship Diagramming MethodVariant of the Critical Path Method of Planning & Scheduling Analysis
Fredric L. Plotnick, Esq., P.E.Engineering & Property Management Consultants, Inc.Benson Manor #117 ā 101 Washington Lane ā Jenkintown, PA 19046
www.fplotnick.com [email protected] 215-885-3733
ā¢ RECENT DEVELOPMENTS highlighted in the professional and technical societies and in academia, relating to the field of CPM Planning and Scheduling, have drawn attention to the focus upon information relating to individual and groups of activities and the lack of focus upon the relationships between these activities that was the hallmark of the original ADM and PERT methodologies
Gantt Charts are Easy to Read
But if you want to make even a small change...
...to the duration of one activity ...you have a great deal of work to perform to determine the impact
??
CPM requires you to record the relationships between activities ...
... and allows the computer to recalculate the impact of changes made ...
... reducing the 40%+ rework effort to that of a keystroke
Logic Network Based Methods
ā¢ CPM ā Critical Path Methodā 1956 E. I. du Pont de Nemours Company, Newark DEā and later known as
ā¢ ADM = Arrow Diagramming Method ā or as AOA = Activity on Arrowā¢ PERT ā Program Evaluation Review Technique
ā 1958 Special Projects Office of the Navy Bureau of Ordinance ā for Research and Development of the Polaris Missile Programā also known as the Program Evaluation Research Task method
ā¢ PDM ā Precedence Diagramming Methodā 1964 IBM implementation for H.B. Zachry Co.ā and also known as AON = Activity on Node
ADMK.I.S.S.
ActivityDescriptioni jduration of
activityES EFLS LF__TF
__TF
TE = = TL
PERT
logic onlyEvent #1Description duration
betweeneventsTE
TLTETL__TF
__TF
Event #2Description
PDM?ActivityDescriptioni jduration of
activity
finish-to-startstart-to-start
finish-to-finishstart-to-finish
start-to-startstart-to-finish
finish-to-startfinish-to-finish
durationbetweenactivities
logic only
ES=TEiLSā„TLi__
TF__TF
EFā¤TEjLF=TLj
PDM
Activityi jduration ofactivity
ES EFLS LF__TF
__TF
finish-to-startstart-to-start
finish-to-finishstart-to-finish
start-to-startstart-to-finish
finish-to-startfinish-to-finish
durationbetweenactivities
logic only
issues with proper usage of non-traditional restraints
A 10
C 10
SS 5
A
B
B 10 FF 5
need never finish
C may start anytime
C may start before NTPA is not required for project completion
visible open endshidden open ends
PDM
Activityi jduration ofactivity
ES EFLS LF__TF
__TF
finish-to-startstart-to-start
finish-to-finishstart-to-finish
start-to-startstart-to-finish
finish-to-startfinish-to-finish
durationbetweenactivities
logic only
issues with continuous versus
interruptible activities
continuous durationinterruptible duration
A 20
B 10
FF5
SS5
A 20
B 10
FF5
SS5
SS5 SS5
PDM
Activityi jduration ofactivity
ES EFLS LF__TF
__TF
finish-to-startstart-to-start
finish-to-finishstart-to-finish
start-to-startstart-to-finish
finish-to-startfinish-to-finish
durationbetweenactivities
logic only
issues with an activity based methodology
Drywall 10
Elect 5PS2 FR2
Drywall 10
Elect 5SS2 FF2
Loop Error Detected
activity A to activity B to activity A loopevent 1 to event 2 no loop
PDM
Activityi jduration ofactivity
ES EFLS LF__TF
__TF
finish-to-startstart-to-start
finish-to-finishstart-to-finish
start-to-startstart-to-finish
finish-to-startfinish-to-finish
durationbetweenactivities
logic only
A OD=10 3 RD=3
B 10
Seven days completeSeven days passed
SS7 Calculated early start of activity B desired when A is 70% complete
A OD=10 5 RD=5
B 10
Five days completeSeven days passed
SS7 Activity A starts on time but loses two days in first weekCalculated early start of activity B is two days early ā when A is 50% complete
issues with measuring from start versus from
partial performance
passage versus progress
PDM
Activityi jduration ofactivity
finish-to-startstart-to-start
finish-to-finishstart-to-finish
start-to-startstart-to-finish
finish-to-startfinish-to-finish
durationbetweenactivities
logic only
partial-to-startpartial-to-finish
finish-to-remainderstart-to-remainder
ES=TELSā¤TL__
TF
TETL__TF
TETL__TF
EFā¤TELF=TL__
TF
āā¦ but what we meant to say ā¦ā
passage versus progress
PDM
ā¢ start B 7 days after A has startedā¢ start B when 7 days of A are completeā¢ start B when 70% of A is completeā¢ start B when 35cy of 50cy is excavated
ā¢ finish B 4 days after A is finishedā¢ finish last 4 days of B after A is finishedā¢ finish last 40% of B after A is finishedā¢ finish last 20cy of 50cy after A is finished
Activityi jduration ofactivity
finish-to-startstart-to-start
finish-to-finishstart-to-finish
start-to-startstart-to-finish
finish-to-startfinish-to-finish
durationbetweenactivities
logic only
partial-to-startpartial-to-finish
finish-to-remainderstart-to-remainder
ES=TELSā¤TL__
TF
TETL__TF
TETL__TF
EFā¤TELF=TL__
TF
āā¦ but what we wanted to say ā¦ā
passage versus progress
Notice toProceed0
FoundationExcavation5
North FDNForm6
South FDNForm6
North FDNStrip1
East FDNForm6
East FDNRebar2
East FDNPour1
East FDNStrip1
North FDNPour1
South FDNPour1
West FDNPour1
South FDNStrip1
West FDNStrip1
FoundationBackfill2
FS 2FS 2 FS 2 FS 2
North FDNRebar2
West FDNForm6
South FDNRebar2
West FDNRebar2
Resources
Scheduling Resources is Not CPM
What can we do?ā¢ Maths of 50s watered down to 50s computersā¢ PCs provide tools (but not skills) to the massesā¢ More powerful PCs benefit glitz ā not mathsā¢ GUI and WYSIWYG i/o favors bar chartingā¢ Wizards further reduce need for skillsā¢ Where is the logic?
Notice toProceed
0
FoundationExcavation
5
North FDNForm
6
North FDNRebar
2
North FDNPour
1
North FDNCure
2
North FDNStrip
1East FDNForm
6
East FDNRebar
2
East FDNPour
1
East FDNCure
2
East FDNStrip
1South FDNForm
6
South FDNRebar
2
South FDNPour
1
South FDNCure
2
South FDNStrip
1West FDNForm
6
West FDNRebar
2
West FDNPour
1
West FDNCure
2
West FDNStrip
1
FoundationBackfill
2
Plan ā then Schedule
Notice toProceed0
FoundationExcavation5
North FDNForm6
North FDNRebar2
North FDNPour1
North FDNStrip1
East FDNForm6
East FDNRebar2
East FDNPour1
East FDNStrip1
South FDNForm6
South FDNRebar2
South FDNPour1
South FDNStrip1
West FDNForm6
West FDNRebar2
West FDNPour1
West FDNStrip1
FoundationBackfill2
FS 2
FS 2
FS 2
FS 2
Notice toProceed
0
FoundationExcavation
5
North FDNForm
6
North FDNRebar
2
North FDNPour
1
North FDNCure
2
North FDNStrip
1East FDNForm
6
East FDNRebar
2
East FDNPour
1
East FDNCure
2
East FDNStrip
1South FDNForm
6
South FDNRebar
2
South FDNPour
1
South FDNCure
2
South FDNStrip
1West FDNForm
6
West FDNRebar
2
West FDNPour
1
West FDNCure
2
West FDNStrip
1
FoundationBackfill
2
Plan ā then Schedule
Notice toProceed0
FoundationExcavation5
North FDNForm6
North FDNRebar2
North FDNPour1
North FDNStrip1
East FDNForm6
East FDNRebar2
East FDNPour1
East FDNStrip1
South FDNForm6
South FDNRebar2
South FDNPour1
South FDNStrip1
West FDNForm6
West FDNRebar2
West FDNPour1
West FDNStrip1
FoundationBackfill2
FS 2
FS 2
FS 2
FS 2
Relationship Diagramming Method
Fredric L. Plotnick, Esq., P.E.Engineering & Property Management Consultants, Inc.Benson Manor #117 ā 101 Washington Lane ā Jenkintown, PA 19046
www.fplotnick.com [email protected] 215-885-3733
RDM
CPM requires you to record the relationships between activities ... ... and allows the computer to recalculate the impact of changes made ...
... reducing the 40%+ rework effort to that of a keystroke
Relationship Diagramming MethodRDM requires you to record the relationships between activities ...
... and allows the computer to recalculate the impact of changes made ...... reducing the 40%+ rework effort to that of a keystroke
more about
Relationship Diagramming Method
ā¢ Four classes of new coding:ā¢ The Event Code ā¢ The Reason Why Codeā¢ The Expanded Lead Lag Codeā¢ The Restraint Relationship Code
Relationship Diagramming Method
ā¢ Four classes of new coding:ā¢ The Event Code ā¢ The Reason Why Codeā¢ The Expanded Lead Lag Codeā¢ The Restraint Relationship Code
Event Codes
ā¢ Internally record and base calculations upon eventsā¢ Events are at start, finish and possibly within an activity
i jEvents ā External and Internal
Event Codes
1440Main Bldg - Install Roofing
10 1 C R 6 RFA12 S23
CrewRoofers
FS 0 1RF1
2440Garage ā Install Roofing
5 1 C R 6 RFA15 S231450Main Bldg ā Studs & Drywall
10 1 I M 4 CPS06 S071460Main Bldg ā Roof HVAC
4 1 I M 4 SMS23 M14
Physical--
FS 0 1--PhysicalPenetrations at 50%
PS 50%
Building Watertight
2440i
1450i
1460i
1440i01 at 2500 SY of 5000 SY
1440i
ā¢ TE ā TJL ā TL ā TV ā T50% ā T90% ā¢ TF ā JTF ā FF ā IF ā¢ TA ā TACOST
ā¢ total v exclusive preds / succsā¢ RDM ā PDM ā ADM ā PERT ā¢ event descriptions or titlesā¢ true milestones
i jEvents ā External and Internal
TETLTF
TETLTF
TETLTF
TETLTF
Event Codes
Relationship Diagramming Method
ā¢ Four classes of new coding:ā¢ The Event Code ā¢ The Reason Why Codeā¢ The Expanded Lead Lag Codeā¢ The Restraint Relationship Code
Reason/Why Codesā¢ Record the reason why the restraint exists
ā physical ā how important ā description ā resource ā crew/craft/equipment/forms/materials/etc.
SS 2 & FF 2Excav 1000 feet - 10 days
Stone 1000 feet - 10 days
Pave 1000 feet - 10 daysSS 2 & FF 2
P ā 1st / last 50 feet P ā 1st / last 50 feet Open Section of Highway
P ā Required
Pave Next Location
R ā Move MachineType of restraint ā P=physical, R=resource ā and reason for restraint and duration between activities
Reason/Why Codesā¢ Record the reason why the restraint exists
ā physical ā how important ā description ā resource ā crew/craft/equipment/forms/materials/etc.
SS 2 & FF 2Excav 1000 feet - 10 days
Stone 1000 feet - 10 days
Pave 1000 feet - 10 daysSS 2 & FF 2
P ā 1st / last 50 feet P ā 1st / last 50 feet Open Section of Highway
P ā Required
Pave Next Location
R ā Move MachineType of restraint ā P=physical, R=resource ā and reason for restraint and duration between activities
Check for:ā¢ physical open endsā¢ duplicative resource logicWhat if:ā¢ add crews/equip/formsā¦?ā¢ add falsework/relax code?
Reason/Why Codesā¢ Special reason why codesā¢ resource ā leveling
ā must suppress (ignore) āRā reason coded restraints for same resourceā L coded restraints are deleted each time the leveling routine is run
Reason/Why Codesā¢ Special reason why codesā¢ physical ā junior or subordinate support
ā calculate latest dates to not delay early start of successor to restraint
Rig & Set
Procure Submit Approve Fabricate Deliver
Pour FdnRebar FdnForm FdnExcavateSurvey P P P P P
P P P PJ = Junior
Junior Late Date & Float Attribute
Legend ā Top Line (Green) is Early Dates, Middle Line (Yellow) is Junior Dates, Bottom Line (Purple) is Late Dates
ā¢ Reason = J / Why = Junior or Subordinate Supportā¢ calculate new attributes JLS, JLF, JTF
Junior Late Date & Float Attribute
Legend ā Top Line (Green) is Early Dates, Middle Line (Yellow) is Junior Dates, Bottom Line (Purple) is Late Dates
Relationship Diagramming Method
ā¢ Four classes of new coding:ā¢ The Event Code ā¢ The Reason Why Codeā¢ The Expanded Lead Lag Codeā¢ The Restraint Relationship Code
Distinguish Passage v Progress ā¢ Interpretation of Start to Start restraint
ā what is meant by start to start?ā start Activity B when 3 days have passed since Activity A was started?ā or start Activity B when 3 days of Activity A have been performed?
Activity A 10 days
Activity B 15 days
Activity A 10 days
Activity B 15 days
versus3 days 3 days
ā¢ Interpretation of Start to Start restraintā what is meant if Lag > OD of Activity A?
ā¢ Interpretation of Start to Start restraintā what is meant if Lag < 0 (negative Lag)?
ā Activity B can be started only after ... two days before Activity A has started?ā Are we modeling what will be observable in the field or just moving bars?
Activity A 10 days
Activity B 15 days
Activity A 10 days
Activity B 15 days
versus
12 days
12 days?
Distinguish Passage v Progress
Activity A 10 days
Activity B 15 days?
Expanded Lead/Lag Codes
use the language of the superintendentā¢ activity āBā may start 7 days after start of activity āAāā¢ activity āBā may start when 7 days of activity āAā completeā¢ activity āBā may start when 70% of activity āAā completeā¢ activity āBā may start when 700 units of activity āAā completeā¢ activity āBā may start when 3 days of activity āAā remainā¢ activity āBā may start when 30% of activity āAā remainā¢ activity āBā may start when 300 units of activity āAā remain
Activity A 10 daysActivity A 1000 CY
Activity B 15 days
??
calc ES or data dateSS 7 1
Act A10 1
Act B
Act C calc ES or actual startBS 7 2
Act A10 1
Act B
Act C
7 days performedPS 7
Act A10 1
Act B
Act C 3 days remainingRS 3
Act A10 1
Act B
Act C
70% performedPS 70%
Act A10 1
Act B
Act C 30% remainingRS 30%
Act A10 1
Act B
Act C
35 yd3 performedPS 35/50
Act A10 1
Act B
Act C 15 yd3 remainingRS 15/50
Act A10 1
Act B
Act C
ā¢ Record āwhat was saidā ā not translation ā of restraintā 7 days after calculated start of remaining scope of work of āAāā 7 days after reported actual start of āAāā 7 (of 10) days completed ā 70% completed ā 35cy (of 50cy) completedā 3 (of 10) days remaining ā 30% remaining ā 15cy (of 50%) remaining
Start-to-Start Restraints
Record rule for out-of-sequence continued progress
ES or data dateSS 7 1
Act A10 1
Act B5 1
Act C8 2
ES or actual startBS 7 2
Act A10 1
Act B5 1
Act C8 2
Record rule for out-of-sequence continued progress
ES or actual startBS 7
Act C Act D
Act E
Act BAct A1001MAY06 12MAY06
10 515MAY06
10 715MAY06 EF=30MAY06
or 06JUN06?
10ES=24MAY06or 07JUN06?
10ES=31MAY06or 07JUN06?
Data Date = 22MAY06Activity C subject to Progress Override ā BS restraint is Actual StartActivity C subject to Retained Logic ā SS restraint is Early Start
Act C Act D
ES or actual finishEF 7 Act E
Act BAct A1001MAY06 12MAY06
10 515MAY06
10ES=22MAY06or 29MAY06?
12 115MAY06EF=29MAY06or 05JUN06?
Data Date = 22MAY06Activity D subject to Progress Override ā EF restraint is Actual FinishActivity D subject to Retained Logic ā FF restraint is Early Finish
10 15MAY06 18MAY06
ā¢ Interpretation of Finish to Finish restraintā what is meant by finish to finish?ā complete Activity B when 2 days have passed since Activity A was completed
ā one second after the two day hiatus?ā but we didnāt say which portion of Activity B could not finish until that time!
ā by the way -- can we split Activity B into two sections?ā or should the start be also delayed to assure a continuous effort?ā note a continuous effort or contiguous portions of an activity are the default in P3
Activity B 10-2 days
Activity A 15 days
2 days
2 days
Activity B 10-4 days
Activity A 15 days
4 days
2 days
Distinguish Passage v Progress
Activity B 10-2 days
Activity A 15 days
2 days
2 days
Finish-to-Finish Restraintsā¢ similar issue of FF v EF restraintā¢ if predecessor to āAā not finished
but A is finished, do we count from the calculated early finish or reported actual finish of āAā
ā¢ note need to choose calendar for FF and EF restraints
ā¢ FR and FP restraints are linked to calendar of activity āCā
ā¢ FF matches retained logic of āCāā¢ EF matches P or M logic override
7 days remaining of CFR 7
Act A Act B
Act C12 1 I M
5 days performed of CFP 5
Act A Act B
Act C12 1 I M
EF or data dateFF 7 2
Act A Act B
Act C12 1 C R
EF or actual finishEF 7 2
Act A Act B
Act C12 1 I M
ā¢ Interpretation of Finish to Start restraintā what is meant by finish to start?ā what is meant by start Activity B when Activity A is complete?ā what is meant by start Activity B 7 days after Activity A is complete?ā what is meant if Lag > OD of Activity A or OD of Activity B?
ā what is meant if Lag < 0 (negative Lag)?ā what part of Activity A is not yet complete?ā what part of Activity A is complete?ā ā what happens if A is never completed?ā ā do we have another hidden open end?
ā what would be meant by FS-12?
Activity A 10 days Activity B 15 days7 days
Activity A 10 days Activity B 15 daysActivity A+ 7 days
Distinguish Passage v Progress
Activity A 10 days
Activity B 15 daysSS+7 FS-3
i j
i j
SS2 PS2 FR3 FF3
RD CPMā¢
Compliance Certified
Relationship Diagramming Critical Path Method
Recap ā SS ā PS ā FR ā FF
2 of 10 days
15 days 3
ā¢ SF ā Start-to-Finish optionally supporting a āpassage of timeā style lag of any durationā While this restraint is generally used merely to āmove the bars on the screen,ā
it occasionally may be used to represent the relationship between the two activities to the best knowledge of the project manager
ā¢ A āprogress of performanceā style of lag is not easily supported ā such would require two lags to represent ā the portion of work performed of the predecessor activity ā prior to ā completion of work of the successor activityā Possible Lead/Lag codes where two lags are provided may include
ā¢ PR ā Progressed-to-Remainingā¢ PP ā Progressed-to-Progressedā¢ RR ā Remaining-to-Remainingā¢ RP ā Remaining-to-Progressed
ā The complexity and additional data entry of two lags one measuring work on the predecessor and one measuring work on the successor required for the above codes may make such impractical.
ā In the event that a SF restraint is used because a āprogressā style restraint is not supported details of the restraint may be noted in the restraint description field.
RD CPMā¢
Compliance Certified
Relationship Diagramming Critical Path Method
7 days performed5 days remainingFS 12 versus PR 7 5
note start of B unimpeded
Activity A 10 days
Activity B 15 days
ā¢ CT ā Contiguousā representing a Finish-to-Start restraint ā where the preceding activity may not start until ā a contiguous and continuous flow of work may occur ā from the start of the predecessor to the finish of the successor
ā¢ The lag portion of this Lead/Lag code ā represents the longest āweekendā permitted between activities
ā¢ The use of this restraint code will be similar to ā assigning a Zero Free Float constraint to the predecessorā affecting the successor activity of THIS restraint only
RD CPMā¢
Compliance Certified
Relationship Diagramming Critical Path Method
Activity A Activity B
ā¢ CC ā Concurrent ā representing the two activities must be performed in lock-stepā this is more than saying two activities joined with SS+FF or PS+FR
RD CPMā¢
Compliance Certified
Relationship Diagramming Critical Path Method
ā¢ CC ā Concurrent ā representing the two activities must be performed in lock-stepā this is more than saying two activities joined with SS+FF or PS+FR
ā¢ Examples include:ā erecting a MSE wall and backfilling during placementā pouring a concrete slab with embedded electrical conduit ā coordination of surgeon and anesthesiologist during an operationā in each instance possibly being performed by separate subcontractors
but under the daily control of only one individual
ā the proper logical means to depict the combination is by only one activity, however the needs for separate rollups by subcontractors and the general desire for such a splitting of this ONE activity indicate a need for this type of restraint code
RD CPMā¢
Compliance Certified
Relationship Diagramming Critical Path Method
ā¢ DS ā Duplicate SS+FF restraints sharing the same lag durationā the MSCS program of the 1960s and 1970s included a popular āZā code = combination of SS+FFā indicates that the early (but not necessarily the late) start of the two activities would start together
or that the two activities (if having the same duration) would be staggeredā note predecessor and successor activities should have the same duration and calendar
An error code should be generated for violations.
ā¢ DP ā Duplicate PS+FR restraints sharing the same lag durationā Similar to the DS restraint, except the successor activity will be calculated to start after the
remaining duration of the predecessor has been reduced by Lag units of time.
ā¢ DR ā Duplicate RS+FP restraints sharing the same lag durationā Similar to the DS restraint, except the successor activity will be calculated to start when the
remaining duration of the predecessor has been reduced to Lag units of time.
RD CPMā¢
Compliance Certified
Relationship Diagramming Critical Path Method
Relationship Diagramming Method
ā¢ Four classes of new coding:ā¢ The Event Codeā¢ The Reason Why Codeā¢ The Expanded Lead Lag Codeā¢ The Restraint Relationship Code
Relationship Codesā¢ Restraint v Relationship Codesā¢ resource codes ā user defined activity codes
ā¢ Calculation āon the fly?āā¢ conduit ā cable ā connections ā energize ā¢ rig pump ā pipe to pump ā run wire to pump
ā¢ Highlight the Handoffā¢ mechanical to electrical subcontractorā¢ crew movement between job area locationsā¢ is there a handoff or demob/remob duration?
event codes & text reason/why codes & textexpanded lead/lag codes relationship codes
Put it all together ā¦
1440Main Bldg - Install Roofing
10 1 C R 6 RFA12 S23
CrewRoofers
FS 2 1RF1
2440Garage ā Install Roofing
5 1 C R 6 RFA15 S231450Main Bldg ā Studs & Drywall
10 1 I M 4 CPS06 S071460Main Bldg ā Roof HVAC
4 1 I M 4 SMS23 M14
Physical--
FS 0 1--
PhysicalPenetrations at 50%
PS 50%
2440i
1450i
1460i
Building Watertight
1440i01 at 2500 SY of 5000 SY
1440i
Beyond RDMā¢ standardized symbols and nomenclature ā¢ record for each activity if continuous / interruptibleā¢ record for each activity rules for out-of-sequence progressā¢ risk and Monte Carloā¢ trend durationsā¢ GERT and non-inclusive logicā¢ multiple leveling priority schemesā¢ distributed scheduling
ā¢ RDM ā Relationship Diagramming Methodā¢ RDCPMā¢ ā Relationship Diagramming Critical Path Method
RD CPMā¢
Compliance Certified
Event #1 Activity #1 ā 10 days50%
Event #2 Activity #2 ā 12 days
Event #3 Activity #3 ā 8 days
Logic #1
Logic #2
Start @ 50%
Event #4 Activity #4 ā 10 daysLogic #3
Start after 5 days
SS 2 & FF 2
Excav 1000 feet - 10 days
Stone 1000 feet - 10 days
Pave 1000 feet - 10 days
SS 2 & FF 2
P ā 1st / last 50 feet P ā 1st / last 50 feet Open Section of Highway
P ā Required
Pave Next Location
R ā Move Machine
1440Main Bldg - Install Roofing
10 1 C R 6 RFA12 S23
CrewRoofers
FS 0 1RF1
2440Garage ā Install Roofing
5 1 C R 6 RFA15 S231450Main Bldg ā Studs & Drywall
10 1 I M 4 CPS06 S071460Main Bldg ā Roof HVAC
4 1 I M 4 SMS23 M14
Physical--
FS 0 1--PhysicalPenetrations at 50%
PS 50%
Building Watertight
2440i
1450i
1460i
1440i01 at 2500 SY of 5000 SY
1440i
Continuous or Interruptible?
ā¢ if continuous ā delays start of activity until all xF restraints completeā¢ if interruptible ā by how much and how often?ā¢ see P3 resource leveling dialog box ā splittingā¢ number of segments ā relate to number of SS or FF restraintsā¢ minimum segment duration ā relate to SS or FF lags
8 10 15 I M
PS 20%
PS 6
FR 3
FS 7 7 10 M
SS 2 3 7 M
PS 7
FF 1 2 5 R
Activityi jdurationES EFLS LF__TF
__TF
ā¢ ESstart = DD = Day 20ā¢ EF = ES + Durā¢ ES = latest EFpredecessors
ā¢ LFfinish = EFfinish
ā¢ LS = LF - Durā¢ LF = earliest LSsuccessors
ā¢ TF = LS - ES ā¢ TF = LF - EF
A B C D
E F
108
5 10 10
7107
20 28 35 45
28 35
35
28 33
35 42
554535
1 2 3
4
5 6
Out-of-Sequence Continued ProgressRetained Logic
Retained Logic vProgress Override
Activity 2-4, āE,ā cannot continue until Activity 1-2, āA,ā is complete
Activityi jdurationES EFLS LF__TF
__TF
ā¢ ESstart = DD = Day 20ā¢ EF = ES + Durā¢ ES = latest EFpredecessors
ā¢ LFfinish = EFfinish
ā¢ LS = LF - Durā¢ LF = earliest LSsuccessors
ā¢ TF = LS - ES ā¢ TF = LF - EF
A B C D
E F
108
5 10 10
7107
20 28 33 43
20 27
27
28 33
27 34
534327
1 2 3
4
5 6
Out-of-Sequence Continued ProgressProgress Override
Retained Logic vProgress Override
Activity 2-4, āE,ā has started and may continue without regard to Activity 1-2
Out-of-Sequence Continued ProgressModified Progress Overrideā¢
Activityi jdurationES EFLS LF__TF
__TF
ā¢ ESstart = DD = Day 20ā¢ EF = ES + Durā¢ ES = latest EFpredecessors
ā¢ LFfinish = EFfinish
ā¢ LS = LF - Durā¢ LF = earliest LSsuccessors
ā¢ TF = LS - ES ā¢ TF = LF - EF
A B C D
E F
108
5 10 10
7107
20 28 33 43
20 28
28
28 33
28 35
534328
1 2 3
4
5 6
Activity 2-4, āE,ā cannot be completeuntil Activity 1-2, āA,ā is complete
Retained Logic vProgress Override- A Third Way? -
Risk and Monte Carlo Simulation
A 10Ā±2
B 10Ā±2
C 10Ā±2
D 10Ā±2
A 10Ā±2B 10Ā±2C 10Ā±2D 10Ā±2ā 40
Project Duration ā 31ā
LATEST DATE 5 JUN 6 EXPECTED DATE 31 MAY 6 EARLIEST DATE 26 MAY 6 TARGET DATE 30 MAY 06
Plot Date 10FEB06 (c) Primavera Systems, Inc.
MONTE CARLO TEST #2Title
Finish Date of Project
MC02MPRJ.MC Sheet 1 of 1
Date Revision Checked Approved
0
10
20
30
40
50
60
70
80
90
100
%
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
%
26 27 28 29 30 31 32 33 34 35 36DAY
Estimating Scheduling
Excerpt from page 142 of CPM in Construction Management
ā¢ for ACTIVITIES āā optimistic, most likely, pessimistic estimate of durationā bell shape, triangular, other distributions
ā¢ for progress style RESTRAINTS āā based upon reference activity
ā¢ for passage style RESTRAINTS āā optimistic, most likely, pessimistic estimate of durationā bell shape, triangular, other distributions
Risk and Monte Carlo Simulation
ā¢ default -15%/+20%, default by group, individual by activity
ā¢ for ACTIVITIES āā based upon any common resourceā based upon any user defined activity code
ā¢ for progress style RESTRAINTS āā based upon reference activity
ā¢ for passage style RESTRAINTS āā based upon any common resourceā based upon any user defined restraint code
Risk and Monte Carlo Simulation
Trend Durationsā¢ for ACTIVITIES ā
ā based upon any common resourceā based upon any user defined activity code
ā¢ for progress style RESTRAINTS āā based upon reference activity
ā¢ for passage style RESTRAINTS āā based upon any common resourceā based upon any user defined restraint code
Notice toProceed
Foundation Excavated
FoundationsPoured
FoundationsBackfilled
3 5 10 1 2 3Select FillCompacted
1 2 4 1 1 2Compaction
Test
PASS
FAIL
0 0 0
1 2 5
ā¢ GERT .or. statementā when Activity A is complete, B .or. C .or. D may startā choosing probability of B, C or D -- random numbersā choosing probability of duration
ā¢ PERT -- Optimistic, Most likely, Pessimisticā¢ extra rock -- Zero to 60 days duration
ā¢ GERT .if. statementā if Activity A is complete when B is complete start C, otherwise start D
ā¢ what other conditions might trigger a decision of which task goes first?
GERT ā Non-Inclusive Logic
multiple leveling priority schemesā¢ no solution to NP Complete problemsā¢ trial and error ā tedium ā rerun for each update
Bestof
Breed
one severalall
Reason = L1 L2 L3 L4 L5
NP CompleteProblem SolutionPatent Pending
Distributed Schedulingā¢ā¢ Issues with hierarchical reporting of projects
Owner
Contractor
Subcontractor
Distributed Schedulingā¢
ā¢activity IDā¢activity descriptionā¢resources assignedā¢resources used TDā¢early start / finishā¢late start / finishā¢sched start / finish
ā¢bid to contractorā¢subcontractor estimateā¢bid from sub-subsā¢cost to dateā¢billed to contractor
ā¢bid to ownerā¢contractor estimateā¢bid from subcontractorā¢cost to dateā¢billed to owner
ā¢commitment by financierā¢engineerās estimateā¢bid from contractorā¢cost to dateā¢paid to contractor
My Project
Owner
Contractor
Subcontractor
Multi-HierarchicalReporting Methodology
Patent Pending
Conclusion
Notice toProceed
0
FoundationExcavation
5
North FDNForm
6
North FDNRebar
2
North FDNPour
1
North FDNCure
2
North FDNStrip
1East FDNForm
6
East FDNRebar
2
East FDNPour
1
East FDNCure
2
East FDNStrip
1South FDNForm
6
South FDNRebar
2
South FDNPour
1
South FDNCure
2
South FDNStrip
1West FDNForm
6
West FDNRebar
2
West FDNPour
1
West FDNCure
2
West FDNStrip
1
FoundationBackfill
2
Notice toProceed0
FoundationExcavation5
North FDNForm6
North FDNRebar2
North FDNPour1
North FDNStrip1
East FDNForm6
East FDNRebar2
East FDNPour1
East FDNStrip1
South FDNForm6
South FDNRebar2
South FDNPour1
South FDNStrip1
West FDNForm6
West FDNRebar2
West FDNPour1
West FDNStrip1
FoundationBackfill2
FS 2
FS 2
FS 2
FS 2
Notice toProceed0 0 0
FoundationExcavation3 5 10
North FDNForm5 6 8
North FDNRebar1 2 3
North FDNPour1 1 2
North FDNCureFS 2 2 2
North FDNStrip1 1 1
East FDNForm5 6 8
East FDNRebar1 2 3
East FDNPour1 1 2
East FDNCureFS 2 2 2
East FDNStrip1 1 1
South FDNForm5 6 8
South FDNRebar1 2 3
South FDNPour1 1 2
South FDNCureFS 2 2 2
South FDNStrip1 1 1
West FDNForm5 6 8
West FDNRebar1 2 3
West FDNPour1 1 2
West FDNCureFS 2 2 2
West FDNStrip1 1 1
FoundationBackfill1 2 3
Physical
Physical
PhysicalPhysical
Physical
Physical
CP Crew
CP Crew
CP Crew
Rod Crew
Rod Crew
Rod Crew
Conc Crew
Conc Crew
Conc Crew
Labor Crew
Labor Crew
Labor Crew
Forms #1
Forms #2
ADM
PDM
RDM
performance of projects is measured by activitiesperformance of projects is driven by relationshipsā¢
RD CPMā¢
Compliance Certified
Questions?Questions?
send further questions to:Fredric L. Plotnick, Esq., P.E.
Benson Manor - Suite #117Jenkintown, PA 19046
or go towww.rdcpm.com
RD CPMā¢
Compliance Certified