Transcript Lecture 9 Deterministic Planning Part II 1.040/1.401 Spring 2007

1.040/1.401
Project Management
Spring 2007
Lecture 9
Deterministic Planning Part II
Dr. SangHyun Lee
[email protected]
Department of Civil and Environmental Engineering
Massachusetts Institute of Technology
Project Management Phase
FEASIBILITY
Fin.&Eval.
Risk
DESIGN
PLANNING
DEVELOPMENT CLOSEOUT
Organization
Estimating
Planning & Scheduling
OPERATIONS
Outline
 Network Techniques
CPM
PDM
 Linear Scheduling Method
Precedence Diagram Method (PDM)
A (10)
Gantt chart
B (10)
A
10
CPM (AON)
Activity B will start right
after Activity A finishes
B
10
A (10)
Activity B will start right
after Activity A starts
B (10)
Precedence Diagram Method (PDM)

PDM Extends CPM to include

Multiple relationships beyond Finish-to-Start

Finish-to-Finish

Start-to-Start

Start-to-Finish
PDM – Types of Relationships

FS Finish-to-start

SS Start-to-start

FF Finish-to-finish

SF Start-to-finish
A
A
A
B
B
B
A
B
Precedence Diagram Method (PDM)
Gantt chart
A (10)
B (10)
CPM (AON)
A
10
B
10
A (10)
Activity B will start 5 days
later after Activity A finishes
(5)
B (10)
A
10
A’
5
Activity B will start after
Activity A finishes
B
10
Precedence Diagram Method (PDM)

PDM Extends CPM to include

Lag (+) & Lead (-)
A (10)
FS (+5)
B (10)
A (10)
FS (-5)
B (10)
PDM Relationships w/ Lag & Lead
Lay-Out & Excavate
Finish-to-Start Lead
Install Fuel Tanks
FS -1
Pour 4th-Floor Slab
Finish-to-Start Lag
Remove 4th Floor Shoring
FS +14
Start-to-Start Lead
SS -1
Backfill Pipe
Install Pipe
Start-to-Start Lag
Install Fuel Tanks
Install Exterior Conduits
SS +1
Adapted from: Callahan et al., 1992
PDM Relationships w/ Lag & Lead
Finish-to-Finish Lead
Form Slab on Grade
FF -1
Reinforce Slab on Grade
Finish-to-Finish Lag
Excavate Trench
FF +3
Lay Pipe
Start-to-Finish Lead
Approve
SF -1
Prepare Wall Shop Drawings
Start-to-Finish Lag
SF +10
Install Wood Paneling & Base
Install Carpeting
Adapted from: Callahan et al., 1992
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 Example
30
10
A
GC
1
C
GC
2
3
40
3
D
EL
2
1
80
90
100
H
ME
K
ME
FINISH
6
1
ES START EF
LS
LF
D SF FNF TF
20
50
B
GC
E
ME
4
2
0
4
2
6
60
70
F
GC
G
EL
3
Source: Callahan et al., 1992
Forward Pass
0
A
GC
30’s ES = 10’s EF + Lag (FS)
30
10
3
1
4
C
GC
6
2
3
40
3
D
EL
2
1
80
90
100
H
ME
K
ME
FINISH
6
1
0 START 0
LS
LF
D SF FNF TF
20
0
B
GC
2
0
50
4
E
ME
4
4
2
6
60
70
F
GC
G
EL
3
Source: Callahan et al., 1992
Forward Pass
30
10
0
A
GC
3
1
4
C
GC
6
MAX
2
3
3
40
7
D
EL
80
9
9
2
1
H
ME
6
0
B
GC
90
15
15
1
0 START 0
LS
LF
D SF FNF TF
20
100’s ES = 90’S EF
100’s ES = 70’s EF
2
K
ME
100
17
17
FINISH
17
0
50
4
4
4
E
ME
8
4
60
2
6
6
F
GC
70
12
12
G
EL
15
3
Source: Callahan et al., 1992
Backward Pass
30
10
0
A
GC
3
1
4
C
GC
6
2
3
3
40
7
D
EL
9
9
6
9
2
1
0
START
D
SF FNF TF
80
0
B
GC
15
15
1
0
20
15
15
2
K
ME
100
17
17
17
17
FINISH
17
17
0
50
4
4
4
E
ME
8
4
60
2
MIN
H
ME
90
70’s LF = 100’S LS
70’s LS = 80’s LF - 1
6
6
F
GC
70
12
12
14
3
G
EL
15
17
Source: Callahan et al., 1992
Backward Pass
30
10
0
0
3
A
GC
3
3
1
4
4
2
C
GC
6
6
3
40
7
7
2
1
0
0
D
D
EL
80
9
9
6
9
9
H
ME
20
0
1
4
MIN
B
GC
15
15
1
0
0
FNF TF
START
SF
90
15
15
2
K
ME
100
17
17
17
17
FINISH
17
17
0
50
4
5
1’s LF = 10’S LS
1’s LF = 20’s LS
4
5
4
E
ME
8
9
60
2
6
8
6
F
GC
70
12
14
12
14
3
G
EL
15
17
Source: Callahan et al., 1992
Total Slack or Float
30
10
0
0
3
A
GC
3
3
0
1
4
4
2
C
GC
6
6
0
TS or TF = LF - ES - D
3
40
7
7
2
1
0
0
D
START
SF FNF
D
EL
80
9
9
6
9
9
0
H
ME
0
0
0
20
0
1
4
B
GC
90
15
15
0
1
15
15
2
K
ME
100
17
17
0
17
17
FINISH
17
17
0
0
50
4
5
1
4
5
4
E
ME
8
9
1
60
2
6
8
6
F
GC
70
12
14
2
12
14
3
G
EL
15
17
2
Source: Callahan et al., 1992
Critical Path
30
10
0
0
3
A
GC
3
3
0
1
4
4
2
C
GC
6
6
0
3
40
7
7
2
1
0
0
D
START
SF FNF
D
EL
80
9
9
6
9
9
0
H
ME
0
0
0
20
0
1
4
B
GC
90
15
15
0
1
15
15
2
K
ME
100
17
17
0
17
17
FINISH
17
17
0
0
50
4
5
1
4
5
4
E
ME
8
9
1
60
2
6
8
6
F
GC
70
12
14
2
12
14
3
G
EL
15
17
2
Source: Callahan et al., 1992
Start & Finish Slack or Float
30
10
0
0
3
A
GC
0
0
3
3
0
1
4
4
2
6
6
0
C
GC
0
0
3
40
7
7
2
1
0
0
D
START
0
0
0
9
9
6
9
9
0
D
EL
0
80
90
15
15
0
H
ME
0
0
0
0
0
20
0
1
4
B
GC
1
1
1
15
15
2
K
ME
0
0
100
17
17
0
17
17
FINISH
17
17
0 0 0 0
50
4
5
1
4
5
4
E
ME
1
1
8
9
1
60
2
6
8
6
F
GC
2
2
70
12
14
2
12
14
3
G
EL
2
2
15
17
2
Source: Callahan et al., 1992
PDM Caveat: Vanishing Critical Path

Tracing critical path can be difficult

Finish-finish constraints with leads can lead to “vanishing” critical path
FF -5
Total float
Duration
PDM Caveat - Counter-Intuitive

Tracing critical path can be difficult

Can be counter-intuitive

The longer A20 is, the smaller the critical path duration and quicker can complete!
A30
FF 2
A20
SS 0
A10
Slack or Float “Ownership”

Tension between owner and contractor

Significant legal implications

Problem:

Owners seek to push contractors on tight schedule


Too many late starts risk overall project duration
Contractors seek flexibility

Flexibility has value
Outline
Network Techniques
CPM
PDM
Linear Scheduling Method
Linear Scheduling Method (LOM)

Line-of-Balance

Time + Location

Repetitive Linear Activities

Rate of Progress (production rate)
LSM Diagram
Source: Callahan et al., 1992
Plotting Activity Progress Lines
Source: Callahan et al., 1992
Use of Restraint on LSM Diagram
Source: Callahan et al., 1992
Activity Interference
Source: Callahan et al., 1992
Use of Activity Buffers in LSM Schedules
Source: Callahan et al., 1992
LSM – Example
LinearPlus
LSM – Example
Tilos