planning and scheduling - cpm

7/24/2019 Planning and Scheduling - CPM

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Planning and Scheduling

Dr. Ir. HM. Agung Wibowo, MM, MSc

Jati Utomo Dwi Hatmoko, ST, MM, MSc, PhD


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Gantt Chart(Mawdesley, 1997)


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Linked Bar Chart(Mawdesley, 1997)


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Techniques of Scheduling

List of Activities

Bar chart / Gantt Chart

Critical Path Method (CPM)

Precedence Diagram Network (PDM)

PERT (Programme Evaluation & ReviewTechnique)

Line of Balance Method

Time Chainage Diagram (Mass HaulDiagram)


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Network

A network is a diagram showing allactivites which are needed to complete aproject and the order of which theymust be done.It therefore comprises two parts :

The activitiesSome method of displaying thetechnological logic of construction.


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Scheduling techniques

1. Bar chart (Gantt chart)2. Network Activity on Arrow (CPM - Critical Path Method)

Arrow Diagramming Method (ADM)

Activity on Node (PDMPrecedence DiagramMethod)


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Network (Mawdesley, 1997)Activity on Arrow


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Activity on Arrow (CPM - Critical Path Method)

North

base

South

base

South

stem

North

stem

North

wwalls

North

backfill

South

wwallsSouth

backfill

Deck

KerbsSurfacing

1 2

3

4

5

6 7 8 9 106 6

15

15

12

12

6

6

20

2 2

0 6

21

21

33

36 48 56 58 60

6058565036

36

21

21

60


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N & S

bases

N

stem

N

wwall

S

stem

S

wwall

S

b/fill

Deck

KerbsSur-

facing

12

15 12

15 12 6 2 21

2

3

4

5

6 20

7 9 10

0

6

activity

name

durationactivity

reference

earlieststart

earliest

finish

KEY

N

b/fill

68

12

6 21 21 33

21 36 36

33 39

48 48 54 56 58 58 60

5636

N

b/fill

68

33 39

0

6 21

21 36

26 38

38 50

36 56

50 56 56 58

50 56

58 6021

latest

start

latest

finish

50 56

12

Activity on Node

(PDMPrecedence Diagram Method)


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Project Scheduling

Steps

Define activities

Sequence activities

Estimate time /duration

Develop schedule

Excavate base

Blind base

Formwork

Reinforcement

Concrete

(4d)

(2d)

(5d)

(4d)

(1d)

Excavate base Blind base Formwork Reinforcement Concrete

4 d 2d 5d 4d 1d


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Linking Activities in the project

A B

A

B

Bar ChartActivity on the arrow

network

A B

Precedence diagram

Activity on B depends on activity A

predecessor successor


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networkPrecedence diagram

AC

A

B

A

CCB B

Activity on C depends on activities A and B



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A CA

B

A C

C

B BDD D

Activity on C and D depends on activities A and B



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A C

A

B

A C

C

B BDD D

Activity on C depends on activity A and D depends on both activities A and B


Dummy


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Only one activity is allowed for two events


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Copyright 2006 John Wiley& Sons, Inc. 9-16

Concurrent Activities

2 3

Lay foundation

Order material

(a) Incorrect precedencerelationship

(b) Correct precedencerelationship

3

42

DummyLay

foundation

Order material

1

2 0


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Using dummies in the network

Excavate (A) Foundation (B) Wall (C)

The Project : 100 m Brickwall

Excavate (A)

Foundation (B)

Wall (C)


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A1 = Excavate base (40m)A2 = Excavate base (30m)A3 = Excavate base (30m)

B1 = Foundation (40m)

B2 = Foundation (30m)B3 = Foundation (30m)

C1 = Wall (40m)C2 = Wall (30m)C3 = Wall (30m)

Activity A(Excavate base 100m)

Activity B(Foundation 100m)

Activity C(Wall 100m)

Excavate (A)

Foundation (B)

Wall (C)


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Only one event at the start, and at the end of the network


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PM

Event i Eventj

i j

iES

jEFActivity A

Duration (d)LS LF

(ES) Early start : the earliest the event i (activity A) can start

(EF) Early finish : the earliest the event j can start or - the earliest the activity A can finish

(LS) Latest start : the latest the event i (activity A) can start without delaying the project

(LF) Latest finish : the latest the event j can start or the latest the activity A can finishwithout delaying the project


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iES

jEFActivity A

Duration (d)LS LF

(ES) Early start = EST (Early Start Time) = EETi (Early Event Time)

(EF) Early finish= EFT (Early FinishTime) = EETj (Early Event Time j)

(LS) Latest start = LST (Latest Start Time) = LETi (Latest Event Time i )

(LF) Latest finish = LFT (Latest FinishTime) = LETi (Latest Event Time j )


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Forward Pass

iES

jEFActivity A

Duration (d)

EF = ES + duration


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Backward Pass

i jActivity A

Duration (d)LS LF

LS = LF - duration


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embankmentalready

constructed

existing ground

profile

existing ground

profile

finished ground

profile

NORTH ABUTMENT SOUTH ABUTMENT

wingwalls stem

base

deck

backfill

embankmentalready

constructed

Activity Name Activity Reference Activity duration (days)

North base 1 6

South base 2 6North abutment stem 3 15

South abutment stem 4 15

North wingwalls 5 12

South wingwalls 8 12

North backfill 7 6

South backfill 6 6

Deck 9 20Kerbs 10 2

Surfacing 11 2

Resource constraint: only one set of formwork is available for

base, one set for abutment stems and one set for wingwalls

12


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North

base

South

base

South

stem

North

stem

North

wwalls

North

backfill

South

wwallsSouth

backfill

Deck

KerbsSurfacing

1 2

3

4

5

6 7 8 9 106 6

15

15

12

12

6

6

20

2 2

0 6

21

21

33

36 48 56 58 60

6058565036

36

21

21

60

FORWARD PASS


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North

base

South

base

South

stem

North

stem

North

wwalls

North

backfill

South

wwallsSouth

backfill

Deck

KerbsSurfacing

1 2

3

4

5

6 7 8 9 106 6

15

15

12

12

6

6

20

2 2

0 6

21

21

33

36 48 56 58 60

6058565036

36

21

21

60

BACKWARD PASS


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North

base

South

base

South

stem

North

stem

North

wwalls

North

backfill

South

wwallsSouth

backfill

Deck

KerbsSurfacing

1 2

3

4

5

6 7 8 9 106 6

15

15

12

12

6

6

20

2 2

0 6

21

21

33

36 48 56 58 60

6058565036

36

21

21

60

Free float (FF) : the maximum time an activity can be delayed without delaying any subsequent

activities that are starting at their earliest times

FF = EFjduration - ESi

iES

jEFActivity A

Duration

(d)LS LF

FF = 0TF= 0

FF =9TF=9

FF =0TF=0

FF =0TF=2

FF =2TF=2

FF =0TF =0

FF =0TF=0

FF =0TF =0

FF =17TF=17FF =0

TF=3FF = 0TF=0


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North

base

South

base

South

stem

North

stem

North

wwalls

North

backfill

South

wwallsSouth

backfill

Deck

KerbsSurfacing

1 2

3

4

5

6 7 8 9 106 6

15

15

12

12

6

6

20

2 2

0 6

21

21

33

36 48 56 58 60

6058565036

36

21

21

60

Total float (TF) : the maximum time an activity can be delayed without delaying the whole project

TF = LFjduration - ESi

iES

jEFActivity A

Duration

(d)LS LFThe Total float is shared by activities in the network.

FF = 0TF= 0

FF =9TF=9

FF =0TF=0

FF =0TF=2

FF =2TF=2

FF =0TF =0

FF =0TF=0

FF =0TF =0

FF =17TF=17FF =0

TF=3FF = 0TF=0

Interferent float (TF) = TF FF


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Activity

Name

Activity

Reference

Activity

duration

(days)

ES i LSi EFj LFj FF TF IF

North base 1 6

South base 2 6

North

abutment

stem

3 15

South

abutment

stem

4 15

North

wingwalls

5 12

South

wingwalls

8 12

North

backfill

7 6

South

backfill

6 6

Deck 9 20

Kerbs 10 2

Surfacing 11 2

We can use a table for this


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Critical Path

North

base

South

base

South

stem

North

stem

North

wwalls

North

backfill

South

wwallsSouth

backfill

Deck

KerbsSurfacing

1 2

3

4

5

6 7 8 9 106 6

15

15

12

12

6

6

20

2 2

0 6

21

21

33

36 48 56 58 60

6058565036

36

21

21

60

The longest path It determines the programme Any delay on the critical path means that the project will be delayed There could be > 1 critical path in the network

Path 1 = NB+SB+SS+SW+SB+K+S = 49Path2 = NB +NS+NW+NB+K+S= 43Path 3 = NB+SB+SS+D+K+S=51Path 4 = NB+NS+SS+SW+SB+K+S=58Path 5 = NB+NS+NW+SW+SB+K+S=55Path 6 = NB+NS+NW+D+K+S=57

Path 7 = NB+NS+SS+D+K+S=60 the critical path

planning and scheduling - cpm

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