cpm scheduling best practicies within the construction indistry

FUNDAMENTALS OF CPM SCHEDULING FOR

CONSTRUCTION PROJECT MANAGERS

Presented By: Michael A. Pink

www.construxsolutions.com 2

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

mpink@construxsolutions.com

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

Follow us on LinkedIn for more info.

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