1.040/1.401 Project Management Spring 2007 Lecture 9 Deterministic Planning Part II Dr. SangHyun Lee Department of Civil and Environmental Engineering Massachusetts Institute of Technology

Project Management Phase FEASIBILITY CLOSEOUT DEVELOPMENT OPERATIONS Fin.&Eval. Risk Estimating Planning & Scheduling DESIGNPLANNING Organization

Outline Network Techniques Network Techniques CPM CPM PDM PDM Linear Scheduling Method Linear Scheduling Method

Precedence Diagram Method (PDM) A (10) B (10) A 10 B 10 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 Method (PDM) PDM Extends CPM to include PDM Extends CPM to include Multiple relationships beyond Finish-to-Start Multiple relationships beyond Finish-to-Start Finish-to-Finish Finish-to-Finish Start-to-Start Start-to-Start Start-to-Finish Start-to-Finish

PDM – Types of Relationships FS Finish-to-start FS Finish-to-start SS Start-to-start SS Start-to-start FF Finish-to-finish FF Finish-to-finish SF Start-to-finish SF Start-to-finish A B A B A B A B

Precedence Diagram Method (PDM) A (10) B (10) A 10 B 10 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 A 10 A5A5 B 10

Precedence Diagram Method (PDM) PDM Extends CPM to include PDM Extends CPM to include Lag (+) & Lead (-) Lag (+) & Lead (-) A (10) B (10) FS (+5) A (10) B (10) FS (-5)

PDM Relationships w/ Lag & Lead Finish-to-Start Lead Finish-to-Start Lag Start-to-Start Lead Start-to-Start Lag FS +14 FS -1 SS -1 SS +1 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-Finish Lead Finish-to-Finish Lag Start-to-Finish Lead Start-to-Finish Lag FF -1 Form Slab on Grade Reinforce Slab on Grade SF +10 Install Wood Paneling & Base Install Carpeting FF +3 Excavate Trench Lay Pipe SF -1 Prepare Wall Shop Drawings Approve Adapted from: Callahan et al., 1992 PDM Relationships w/ Lag & Lead

Slack or Float in PDM n Total Float (TF) TF(k) = LF(k) - ES(k) - D k n Start Float (SF) SF(k) = LS(k) - ES(k) n Finish Float (FNF) FNF(k) = LF(k) - EF(k)

PDM Example Source: Callahan et al., 1992 TF D ES LS EF LF SF FNF START B GC 20 2 D EL 40 4 E ME 50 6 F GC 60 6 H ME 80 3 G EL 70 0 FINISH K ME A GC 10 2 C GC 30

Forward Pass Source: Callahan et al., 1992 TF D 0 LS 0 LF SF FNF START B GC 20 2 D EL 40 4 E ME 50 6 F GC 60 6 H ME 80 3 G EL 70 0 FINISH K ME A GC 10 2 C GC s ES = 10s EF + Lag (FS)

Forward Pass Source: Callahan et al., 1992 TF D 0 LS 0 LF SF FNF START B GC 20 2 D EL 40 4 E ME 50 6 F GC 60 6 H ME 80 3 G EL 70 0 FINISH K ME A GC 10 2 C GC s ES = 90S EF 100s ES = 70s EF MAX

Backward Pass Source: Callahan et al., 1992 TF D 0 0 SF FNF START B GC 20 2 D EL 40 4 E ME 50 6 F GC 60 6 H ME 80 3 G EL 70 0 FINISH K ME A GC 10 2 C GC s LF = 100S LS 70s LS = 80s LF - 1 MIN

Backward Pass Source: Callahan et al., 1992 TF D SF FNF START B GC 20 2 D EL 40 4 E ME 50 6 F GC 60 6 H ME 80 3 G EL 70 0 FINISH K ME A GC 10 2 C GC s LF = 10S LS 1s LF = 20s LS MIN

Total Slack or Float Source: Callahan et al., D SF FNF START B GC 20 2 D EL 40 4 E ME 50 6 F GC 60 6 H ME 80 3 G EL 70 0 FINISH K ME A GC 10 2 C GC TS or TF = LF - ES - D

Critical Path Source: Callahan et al., D SF FNF START B GC 20 2 D EL 40 4 E ME 50 6 F GC 60 6 H ME 80 3 G EL 70 0 FINISH K ME A GC 10 2 C GC

Start & Finish Slack or Float Source: Callahan et al., D START B GC 20 2 D EL 40 4 E ME 50 6 F GC 60 6 H ME 80 3 G EL 70 0 FINISH K ME A GC 10 2 C GC

PDM Caveat: Vanishing Critical Path Tracing critical path can be difficult Tracing critical path can be difficult Finish-finish constraints with leads can lead to vanishing critical path Finish-finish constraints with leads can lead to vanishing critical path FF -5 Total float Duration

PDM Caveat - Counter-Intuitive A30 A20 FF 2 A10 SS 0 Tracing critical path can be difficult Tracing critical path can be difficult Can be counter-intuitive Can be counter-intuitive The longer A20 is, the smaller the critical path duration and quicker can complete!

Slack or Float Ownership Tension between owner and contractor Tension between owner and contractor Significant legal implications Significant 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 duration Too many late starts risk overall project duration Contractors seek flexibility Contractors seek flexibility Flexibility has value Flexibility has value

Outline Network Techniques Network Techniques CPM CPM PDM PDM Linear Scheduling Method Linear Scheduling Method

Linear Scheduling Method (LOM) Line-of-Balance Line-of-Balance Time + Location Time + Location Repetitive Linear Activities Repetitive Linear Activities Rate of Progress (production rate) 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