cpm scheduling best practicies within the construction indistry
TRANSCRIPT
FUNDAMENTALS OF CPM SCHEDULING FOR
CONSTRUCTION PROJECT MANAGERS
Presented By: Michael A. Pink
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ABOUT THE PRESENTER: MICHAEL PINK
Founder of Construx Solutions, LLC
Inventor of the SmartPM Technology
15 Years of Advisory Experience in Commercial Construction Industry
Specialization in Project Controls, Risk Management, Dispute Avoidance
Advisory Board Member for the School of Building Construction at GT
Certified Planning and Scheduling Professional
Certified Cost Engineer
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COURSE OBJECTIVES
Critical Path Method (CPM) Scheduling Explained
Baseline CPM Schedules – Recommendations for Strong Schedules
Schedule Updates – Best Practices for Generating “Usable” Updates
Lean Construction Planning 101
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THE BASICS – WHAT IS CPM?
CPM Stands for “Critical Path Method”
What is the “Critical Path”?
Why are CPM Schedule’s Useful?
Schedules in Excel and Visio are not CPM
Critical Path Method scheduling is a mathematically based technique (or algorithm)that is used for scheduling an interdependent set’s of activities. The CPM methodfirst requires that all activities, durations, constraints and relationships are defined.Once established, the algorithm generates a schedule based on the aboveinformation. Within that schedule, there are 2 types of paths: “Critical” and “NonCritical” Paths. The “Critical” path is the only path that extends from start to finish ofthe project – with no room for delay. Every other path is considered “Non Critical”
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THE BASICS – WHAT IS CPM?
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THE BASICS – CPM SCHEDULING TERMINOLOGY
Activity (or Task) – A discrete scheduled component of work to be performed during the
course of a project.
Milestone – A significant event in the project schedule, such as an event restraining
future work (watertight milestone) or marking the completion of a major milestone
(substantial completion).
Planned Duration – The total number of working days estimated to complete a
schedule activity.
Resource Estimates – The estimated quantity (and types) of resources required to
perform each schedule activity.
Logical Relationship – A dependency between two schedule activities, or between a
schedule activity and a schedule milestone.
Predecessor – An activity required to be completed prior to the start of a
(successor) activity.
Successor – An activity that follows the start/completion of a (predecessor) activity.
Float – The number of days an activity can be delayed before impacting a successor (or
the end date of the project)
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THE BASICS – BUILDING A CPM “BASELINE” SCHEDULE
Step 1: Choose a CPM Scheduling Technology (NOT Excel)
Step 2: List All Activities/Tasks Necessary to Build the Project
Step 3: Set Durations for Each Activity (Risk Adjusted if Possible)
Step 4: Apply Necessary Relationships amongst Activities
Step 5: Apply Necessary Constraints (Date, Crew, Calendars, etc.)
Additional Recommended Best Practices:
Step 6: Set Organizational Structure (Activity Codes or WBS)
Step 7: Resource/Cost Load Activities
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THE BASICS – PREPARING THE ACTIVITY LIST
Include all activities required to complete the work (this is a no brainer,
but still requires quite a bit of thought)
This includes discussions with PM’s and Superintendents
Subcontractor Schedule Submissions are useful prior to finalizing
Activities should not be too broad and not to detailed
5 (min) – 20 (max) working days each (1 week to 1 month durations)
A maximum of 100 activities per trade for the project
Don’t exceed 2000 activities
Crews and/or process/order are very important
Early coordination discussions between CM’s and Subs is useful
Must have achievable crew sizes
Give some thought to the Activity Code / WBS Structure
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THE BASICS – ESTIMATING ACTIVITY DURATIONS
Consider Resources Required to estimate “Best Case” Durations:
Visualize the Space and Estimate an Efficient Crew Size
Use Estimate to Determined Planned Man-hours/days for the Activity at hand
Divide Number of Estimated Man-days / Estimated Crew Size to get “Best
Case Scenario” Activity Duration.
Enter into First Draft of CPM Schedule
Review CPM Schedule and modify Durations to Account for Risk items:
Need to Consider Crew Restraints
Need to Consider Trade-Stacking
Need to Consider Delay Issues that could arise
Important: The more “Best Case” Durations that exist in the Schedule, the
higher the risk of budget overruns and delays.
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THE BASICS – SETTING ACTIVITY RELATIONSHIPS
“Logic” is the building blocks for a CPM schedule.
Understanding of the Various Relationship Types:
Finish to Start Relationship
Start to Start Relationship
Finish to Finish Relationship
Start to Finish Relationship
What is Lag?
All activities should have a predecessor and successor
(except for the first and last activities/milestones)
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EXAMPLES OF RELATIONSHIP TYPES – FINISH TO START
Predecessor
Successor
Finish-to-Start, Lag 0
Predecessor
Successor
Finish-to-Start, Lag 2
Predecessor
Successor
Finish-to-Start, Lag -2
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EXAMPLES OF RELATIONSHIP TYPES – START TO START
Predecessor
Successor
Start-to-Start, Lag 0
Predecessor
Successor
Start-to-Start, Lag 2
Predecessor
Successor
Start-to-Start, Lag -2 Not Recommended
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EXAMPLES OF RELATIONSHIP TYPES – FINISH TO FINISH
Predecessor
Successor
Finish-to-Finish, Lag 0
Predecessor
Successor
Finish-to-Finish, Lag 2
Predecessor
Successor
Finish-to-Finish, Lag -2
Not Recommended
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THE BASICS – UNDERSTANDING CONSTRAINTS
Start/Finish Constraints Availability Constraints
Government Requirements
Contractual
No Real Predecessors/Successors
Crew Management Crew Leveling
Availability of Area
Trade Stacking
Calendar Constraints Union Requirements
Acceleration Requirement
Seasonal Constraints
Preference
Mandatory Start
Mandatory Finish
Start On or After
Start On or Before
Finish On or After
Finish On or Before
As Late as Possible
Constraint Types Examples
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QUESTIONS?
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SCHEDULE UPDATES – BASICS
What is a Schedule Update?
Why are Schedule Updates Useful?
Recommended Scheduling Updating Process:
1. Activity Status Discussions between Schedulers and Project Management
2. Scheduler to upload activity status into the schedule and study results
3. Delays need to be discussed with Project Mgt., Supers and Subs
4. Conduct Planning/Mitigation Meetings with Site Team (PM’s, Supers, Subs)
5. Update go forward schedule based on discussions held (incl. mitigation Strategy)
Schedulers who have limited knowledge on what’s going on in the field
should not modify logic or durations (ie. mitigate) “on the fly”
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SCHEDULE UPDATING – DO’S AND DON’TS
DO DON’T
Status Schedules Updates in Real Time Issue Schedule Updates 1+ Months late
Update Schedules on a consistent basis (Week/Month) Update Schedules less than once per Month
Modify Plan based on Discussion’s Held in Coordination/Strategy Meetings
Modify Plan without Field Input
Adjust Plan based on Historical PerformanceLeave Incomplete Activity Durations pegged to the
Original Anticipated Durations
Incorporate Resource/Trade Constraints when Updating Crash the Schedule
Document (and substantiate) all modifications to activity status, logic, durations, etc.
Update Activity Status and modify Logic, duration, etc. w/o substantiating
Perform a Monthly Delay Analysis and Mitigation Summary
Save Delay Analysis until the end of the Project
Produce and Utilize 3 Week Look-Ahead SchedulesHope that everyone has a copy of the Latest CPM and
will figure it out themselves
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SCHEDULE UPDATES – IMPORTANT RULES
Use Historical Data/Info to Produce Realistic Future Projections
Update Schedule with Data; Review; Modify
Collaborate/Coordinate with Field Personnel to form Mitigation Strategies
Use Feasible Logic Structures when Mitigating Delay
Know the Resource Pool and Incorporate Crew Constraints
Avoid Trade Stacking / Crew Spreading
Have Discussions with other Stakeholders, Be Transparent.
Fear the Crash – Crashing Schedules leads to claims
ALWAYS COMPARE CURRENT SCHEDULE TO THE APPROVED PLAN
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CASE STUDY – UPDATING THE SCHEDULE AND
COMPARING TO THE ORIGINAL PLAN
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UPDATE WEEK 1
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UPDATE WEEK 2
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UPDATE WEEK 3
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QUESTIONS?
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LEAN CONSTRUCTION 101
Lean Construction results from the Toyota Lean Manufacturing System
Lean Construction is belief that cost can be saved by minimizing waste
Lean is a system of effectively organizing time and space in Commercial
Construction
Focuses on Collaboration across all Phases of Construction with all
Stakeholders to minimize waste
Performance Oversight Measures are Integral to Success
http://vimeo.com/63199577
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FOCUS IS ON ELIMINATION OF WASTE
Of the 3, Labor Costs are the largest “Risk” in the Construction Estimate.
Labor Costs are the most highly correlated to cost fluctuations.
Lean Construction is a system designed to minimize labor costs, by adding efficiencies.
Managing Labor Cost Variances result in a Competitive Advantage in Construction
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EXAMPLES OF WASTE
Transportation Material Handling Motion
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LEAN PLANNING
CPM scheduling is not enough, since CPM is Hypothetical;
CPM schedules should be used as a basis for Lean Planning
It is necessary to plan in real time to adjust and account for real world scenarios.
Weekly Collaboration/Review Meetings are Required
Beginning of the Week: 3-6 week look ahead / “Pull Planning” / Collaboration Sessions with Field Team (PM’s, Supers, Foreman, Subs) to figure out near term schedules;
Teams should discuss efficiencies, incorporate risk into activity durations, and determine deliveries to prepare a “collaborated” 6 week plan (that all parties can agree to)
Teams are left to Perform the next week in line with what was discussed; End of the week performance reviews should be held between Scheduler’s, PM’s and Field
members/Subs. Need to discuss impacts, correction measures and Rate Performance (info/data to be used for
following week’s meeting).
Understanding Impacts is imperative to achieve for Lean Planning
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LEAN SCHEDULING – ASSESSING BREAKDOWNS
Coordination
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LEAN ASSEMBLY – SITE PLANNING
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LEAN ASSEMBLY – DAILY HUDDLES
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LEAN SUPPLY
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PRESENTED BY: MICHAEL PINK
Contact Info:
C: 404 277 4387
O: 404 329 3000
Feel free to contact me directly if
you have any additional questions
Sign up for our upcoming courses:
— Data Management and Performance Analysis
— Delay Analysis in Construction
— Construction Claims Review/Prep
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