1.040/1.4011.040/1.401Project ManagementProject Management

Spring 2007Spring 2007

Lecture 9Lecture 9Deterministic Planning Part IIDeterministic Planning Part II

Dr. SangHyun Leelsh@mit.edulsh@mit.edu

Department of Civil and Environmental Department of Civil and Environmental EngineeringEngineering

Massachusetts Institute of Technology Massachusetts Institute of Technology

Project Management Project Management PhasePhase

FEASIBILITY

CLOSEOUTDEVELOPMENT OPERATIONS

Fin.&Eval.Risk

Estimating

Planning & SchedulingPlanning & Scheduling

DESIGNDESIGNPLANNING PLANNING

Organization

OutlineOutline

Network TechniquesNetwork Techniques CPMCPM

PDMPDM

Linear Scheduling MethodLinear Scheduling Method

Precedence Diagram Precedence Diagram Method (PDM)Method (PDM)

A (10)

B (10)

A10

B10

Gantt chart

CPM (AON)

Activity B will start right after Activity A finishes

A (10)

B (10)

Activity B will start right after Activity A starts

Precedence Diagram Precedence Diagram Method (PDM)Method (PDM)

PDM Extends CPM to includePDM Extends CPM to include

Multiple relationships beyond Finish-to-StartMultiple relationships beyond Finish-to-Start

Finish-to-FinishFinish-to-Finish

Start-to-StartStart-to-Start

Start-to-FinishStart-to-Finish

PDM – Types of PDM – Types of RelationshipsRelationships

FS Finish-to-startFS Finish-to-start

SS Start-to-startSS Start-to-start

FF Finish-to-FF Finish-to-finishfinish

SF Start-to-finishSF Start-to-finish

A B

A B

A B

A

B

Precedence Diagram Precedence Diagram Method (PDM)Method (PDM)

A (10)

B (10)

A10

B10

Gantt chart

CPM (AON)

Activity B will start after Activity A finishes

A (10)

B (10)

(5)Activity B will start 5 days later after Activity A finishes

A10

A’5

B10

Precedence Diagram Precedence Diagram Method (PDM)Method (PDM)

PDM Extends CPM to includePDM Extends CPM to include

Lag (+) & Lead (-)Lag (+) & Lead (-)

A (10)

B (10)

FS (+5)

A (10)

B (10)

FS (-5)

PDM Relationships w/ Lag & PDM Relationships w/ Lag & LeadLead

Finish-to-StartFinish-to-Start LeadLead

Finish-to-StartFinish-to-Start LagLag

Start-to-StartStart-to-Start LeadLead

Start-to-StartStart-to-Start LagLag

FS FS ++1414

FS FS --11

SS SS --11

SS SS ++11

Lay-Out & Excavate

Install Fuel Tanks

Pour 4th-Floor Slab

Remove 4th Floor Shoring

Backfill Pipe

Install Pipe

Install Fuel Tanks

Install Exterior Conduits

Adapted from: Callahan et al., 1992

Finish-to-FinishFinish-to-Finish LeadLead

Finish-to-FinishFinish-to-Finish LagLag

Start-to-FinishStart-to-Finish LeadLead

Start-to-FinishStart-to-Finish LagLag

FF FF --11

Form Slab on Grade

Reinforce Slab on Grade

SF SF ++1010Install Wood Paneling & Base

Install Carpeting

FF FF ++33Excavate Trench

Lay Pipe

SF SF --11Prepare Wall Shop Drawings

Approve

Adapted from: Callahan et al., 1992

PDM Relationships w/ Lag & PDM Relationships w/ Lag & LeadLead

Slack or Float in PDM

Total Float (TF)

• TF(k) = LF(k) - ES(k) - Dk

Start Float (SF)

• SF(k) = LS(k) - ES(k)

Finish Float (FNF)

• FNF(k) = LF(k) - EF(k)

PDM ExamplePDM Example

Source: Callahan et al., 1992

TFD

ESLS

EFLF

SF FNF

START

1

3

4

BGC

20

2

DEL

40

4

EME

50

6

FGC

60

6

HME

80

3

GEL

70

0

FINISH

100

2

KME

90

11

33

22

11

AGC

10

2

CGC

30

Forward PassForward Pass

Source: Callahan et al., 1992

TFD

0LS

0LF

SF FNF

START

1

3

4

BGC

20

2

DEL

40

4

EME

50

6

FGC

60

6

HME

80

3

GEL

70

0

FINISH

100

2

KME

90

11

33

22

11

AGC

10

2

CGC

300 3 4 6

0 4

30’s ES = 10’s EF + Lag (FS)

Forward PassForward Pass

Source: Callahan et al., 1992

TFD

0LS

0LF

SF FNF

START

1

3

4

BGC

20

2

DEL

40

4

EME

50

6

FGC

60

6

HME

80

3

GEL

70

0

FINISH

100

2

KME

90

11

33

22

11

AGC

10

2

CGC

300 3 4 6

0 4

7 9

4 8

6 12 12 15

9 15 15 17 17 17

100’s ES = 90’S EF100’s ES = 70’s EFMAX

Backward PassBackward Pass

Source: Callahan et al., 1992

TFD

0 0

SF FNF

START

1

3

4

BGC

20

2

DEL

40

4

EME

50

6

FGC

60

6

HME

80

3

GEL

70

0

FINISH

100

2

KME

90

11

33

22

11

AGC

10

2

CGC

300 3 4 6

0 4

7 9

4 8

6 12 12 15

9 15 15 17 17 1717 1715 17

14 17

9 15

70’s LF = 100’S LS70’s LS = 80’s LF - 1

MIN

Backward PassBackward Pass

Source: Callahan et al., 1992

TFD

00

00

SF FNF

START

1

3

4

BGC

20

2

DEL

40

4

EME

50

6

FGC

60

6

HME

80

3

GEL

70

0

FINISH

100

2

KME

90

11

33

22

11

AGC

10

2

CGC

300 3 4 6

0 4

7 9

4 8

6 12 12 15

9 15 15 17 17 1717 1715 17

14 17

9 157 9

8 14

5 9

4 6

1 5

0 3

1’s LF = 10’S LS1’s LF = 20’s LS

MIN

Total Slack or FloatTotal Slack or Float

Source: Callahan et al., 1992

0D

00

00

SF FNF

START

1

3

4

BGC

20

2

DEL

40

4

EME

50

6

FGC

60

6

HME

80

3

GEL

70

0

FINISH

100

2

KME

90

11

33

22

11

AGC

10

2

CGC

300 3 4 6

0 4

7 9

4 8

6 12 12 15

9 15 15 17 17 1717 1715 17

14 17

9 157 9

8 14

5 9

4 6

1 5

0 30 0

0 0 0 0

22

11

TS or TF = LF - ES - D

Critical PathCritical Path

Source: Callahan et al., 1992

0D

00

00

SF FNF

START

1

3

4

BGC

20

2

DEL

40

4

EME

50

6

FGC

60

6

HME

80

3

GEL

70

0

FINISH

100

2

KME

90

11

33

22

11

AGC

10

2

CGC

300 3 4 6

0 4

7 9

4 8

6 12 12 15

9 15 15 17 17 1717 1715 17

14 17

9 157 9

8 14

5 9

4 6

1 5

0 30 0

0 0 0 0

22

11

Start & Finish Slack or Start & Finish Slack or FloatFloat

Source: Callahan et al., 1992

0D

00

00

0 0

START

1

3

4

BGC

20

2

DEL

40

4

EME

50

6

FGC

60

6

HME

80

3

GEL

70

0

FINISH

100

2

KME

90

11

33

22

11

AGC

10

2

CGC

300 3 4 6

0 4

7 9

4 8

6 12 12 15

9 15 15 17 17 1717 1715 17

14 17

9 157 9

8 14

5 9

4 6

1 5

0 30 0

0 0 0 0

22

11

0 0 0 0

0 0 0 0 0 0 0 0

2 22 2

1 11 1

PDM Caveat: Vanishing PDM Caveat: Vanishing Critical PathCritical Path

Tracing critical path can be difficultTracing critical path can be difficult Finish-finish constraints with leads can lead to Finish-finish constraints with leads can lead to

“vanishing” critical path“vanishing” critical path

FF -5

Total float

Duration

PDM Caveat - Counter-PDM Caveat - Counter-IntuitiveIntuitive

A30

A20

FF 2

A10

SS 0

Tracing critical path can be difficultTracing critical path can be difficult Can be counter-intuitiveCan be counter-intuitive

The longer A20 is, the smaller the critical path duration and quicker can complete!

Slack or Float Slack or Float “Ownership”“Ownership”

Tension between owner and contractorTension between owner and contractor

Significant legal implicationsSignificant legal implications

Problem: Problem:

Owners seek to push contractors on tight schedule Owners seek to push contractors on tight schedule

Too many late starts risk overall project durationToo many late starts risk overall project duration

Contractors seek flexibilityContractors seek flexibility

Flexibility has valueFlexibility has value

OutlineOutline

Network TechniquesNetwork Techniques CPMCPM

PDMPDM

Linear Scheduling MethodLinear Scheduling Method

Linear Scheduling Method Linear Scheduling Method (LOM)(LOM)

Line-of-BalanceLine-of-Balance

Time + LocationTime + Location

Repetitive Linear ActivitiesRepetitive Linear Activities

Rate of Progress (production rate)Rate of Progress (production rate)

LSM DiagramLSM Diagram

Source: Callahan et al., 1992

Plotting Activity Progress Plotting Activity Progress LinesLines

Source: Callahan et al., 1992

Use of Restraint on LSM Use of Restraint on LSM DiagramDiagram

Source: Callahan et al., 1992

Activity InterferenceActivity Interference

Source: Callahan et al., 1992

Use of Activity Buffers in LSM Use of Activity Buffers in LSM SchedulesSchedules

Source: Callahan et al., 1992

LSM – ExampleLSM – Example

LinearPlus

LSM – ExampleLSM – Example

Tilos