Construction Project Scheduling and Control

SALEH MUBARAK, PHD, is an independent consultant in the field of construction project management, based in Tampa, Florida, focusing on training, writing, public speaking, and consulting. He is a former professor at a number of universities and an active member of PMI and AACE International. He served on the PMI committee that created the professional scheduler certification exam, PMI-SP. He has 30 years of diversified and international experience including academia and industry; private and public sectors. He is also the author of How to Estimate with RSMeans Data, published by Wiley.

• Preface xiiiPreface to the First Edition xviiChapter 1 Introduction 1Planning and Scheduling 2What is a Project? 2Are Projects Unique? 4Project Management Plan 7Project Control 8Why Schedule Projects? 8The Scheduler 11Certification 11The Tripod of a Good Scheduling System 12Scheduling and Project Management 12Chapter 1 Exercises 13Chapter 2 Bar (Gantt) Charts 15Definition and Introduction 16Advantages of Bar Charts 18Disadvantages of Bar Charts 20Chapter 2 Exercises 21Chapter 3 Basic Networks 23Definition and Introduction 24Arrow Networks 24Brief Explanation 24The Logic 25Notation 25Dummy Activities 26Redundancies 31Node Networks 31Lags and Leads 32Recommendations for Proper Node Diagram Drawing 35Comparison of Arrow and Node Networks 37Networks versus Bar Charts 39Effective Use of Bar Charts with CPM 40Time-Scaled Logic Diagrams 40Chapter 3 Exercises 41Chapter 4 The Critical Path Method (CPM) 45Introduction 46Steps Required to Schedule a Project 47Main Steps 47Supplemental Steps 55Resource Allocation and Leveling 57Beginning-of-Day or End-of-Day Convention 59The CPM Explained through Examples 59Example 4.1: Logic Networks and the CPM 59The CPM with Computer Software Programs 63The Critical Path 64Definitions 65Examples 4.2 and 4.3: Node Diagrams and the CPM 66Free Float 67More Definitions 70Float Check 71Node Format 72Lags and Leads in CPM Networks 73Lags and Leads in Computer Software 76Further Discussion of Float 76Effect of Date Choices on Cash Flow 78Project Schedule “Health Check” 78Event Times in Arrow Networks 79Effect of the Imposed Finish Date on the Schedule 81Discussion of Example 4.7 82Logic and Constraints 84The “Hub” Concept 85The Critical Path Method and Scheduling 85Chapter 4 Exercises 86Chapter 5 Precedence Networks 93Definition and Introduction 94The Four Types of Relationships 97Important Comments about the Four Types of Relationships 98The Percent Complete Approach 98Fast-Track Projects 99A Parallel Predecessor? 101CPM Calculations for Precedence Diagrams 102Interruptible Activities 102The Simplistic Approach 105Alternative Approach 107The Detailed Approach 110Contiguous (Uninterruptible) Activities 113Remedy for Interruptible Activities 117Multistage Activities 120Types of Lags 121Final Discussion 123Chapter 5 Exercises 124Chapter 6 Resource Allocation and Resource Leveling 129Introduction 130The Three Categories of Resources 130Labor 130Equipment and Materials 130What is Resource Allocation? 131Resource Leveling 131What is Resource Leveling? 131Why Level Resources? 131Do All Resources Have to Be Leveled? 132Multiproject Resource Leveling 132Assigning Budgets in Computer Scheduling Programs 134Leveling Resources in a Project 136Resource Leveling from the General Contractor’s Perspective 153Materials Management 155Chapter 6 Exercises 159Chapter 7 Schedule Updating and Project Control 163Introduction 164The Need for Schedule Updating 164Project Control Defined 164Schedule Updating 165What is a Baseline Schedule? 165What is an Updated Schedule? 167What is the Data Date? 168What Kind of Information is Needed for Updating Schedules? 168Frequency of Updating 171Retained Logic or Progress Override 172Auto-Updating 172Updating Schedules and Pay Requests 173“Degressing” an In-Progress Schedule to Create a Baseline Schedule 175Effect of Adding or Deleting Activities on Logic 176Steps for Updating a Schedule 180Change in the Critical Path 191Float after the Update 191Contractor-Created Float 192Data and Information 193Project Control 194Measuring Work Progress 194Earned Value Analysis 208Chapter 7 Exercises 217Chapter 8 Schedule Compression and Time-Cost Trade-Off 223Introduction 224How Important is It to Finish on Schedule? 225Setting Priorities 225Accelerating a Project 226What is “Accelerating” a Project? 226Why Accelerate a Project? 226How Can Project Duration Be Shortened? 227Acceleration and Fast-Tracking 235Construction and Modularization 235How Does Accelerating a Project Work? 236Direct and Indirect Costs 238Cost Concepts as They Relate to Schedule Compression 240Choosing the Best Method for Project Acceleration 240Effect of Acceleration on Direct Costs 241Effect of Acceleration on Indirect Costs 242Effect of Acceleration on Total Cost 243Issues to Consider When Accelerating a Project 245Recovery Schedules 247Accelerating Projects Using Computers 252Potential Issues with Uncoordinated Project Acceleration 253Optimum Project Scheduling 254Project Scheduling and Prevailing Economic Conditions 255Project Scheduling in Extreme Weather Regions 256Optimum Scheduling 256Productivity and Cost Multipliers 258Chapter 8 Exercises 260Chapter 9 Reports and Presentations 265Introduction 266The Difference between Reports and Presentations 270Skills Necessary for Giving Good Presentations 272The Power of Presentations 273Reviewing Reports before and after Printing 275General Tips on Printing Reports 276Summary Reports 277Paper or Electronic Reports? 277E-Reports 280Communications in the International Environment 280Chapter 9 Exercises 282Chapter 10 Scheduling as Part of the Project Management Effort 285Introduction 286Project Objectives 287Defining and Measuring Project Success 288Scheduling and Estimating 290Evolution of a Cost Estimate and a Schedule for a Project 291Estimate-Generated Schedules 294Cost-Loaded Schedules 296Estimating and Accounting 296Scheduling and Accounting 298Scheduling and Change Orders 298Paperless Project Management 299Procurement Management 300Management of Submittals 301The Master Schedule and Subschedules 303Multiproject Management 304Time Contingency and Management Options 305Chapter 10 Exercises 308Chapter 11 Other Scheduling Methods 311Introduction 312Program Evaluation and Review Technique (PERT) 312Background 312Concept of PERT 312How PERT Works 313PERT Calculations 313Graphic Explanation 316“Most Likely” versus “Expected” Durations 323Is the Longest Path Still the Most Critical? 323Using PERT to Calculate the Date of an Event with a Certain Level of Confidence 326Determining the Probability of a Certain Project Finish Date (Multiple Paths Considered) 327PERT and the Construction Industry 328PERT and Computer Project-Scheduling Software 328Graphical Evaluation and Review Technique (GERT) 329Linear Scheduling Method (LSM) 330Steps to Build a Schedule Using the LSM 331How the LSM Works 331LSM and Project Schedule Acceleration 337LSM Computer Software Programs 337Graphical Path Method (GPM) 338Relationship Diagramming Method (RDM) 342The Critical Path Segments (CPS) Scheduling Technique 346Chapter 11 Exercises 348Chapter 12 Dynamic Minimum Lag Relationship 353Introduction 354Why DML? 354Similarity between the DML Concept and the Linear Scheduling Method (LSM) 355How Does DML Work? 356DML Relationship in CPM Calculations 358Can the Lag in the DML Relationship Be a Percentage? 359Conclusion 365Chapter 12 Exercises 366Chapter 13 The Critical Path Definition: Revisited 367Introduction 367What is the “Longest Path”? 368The Critical Path through Examples 369The Simple Case 369Imposed Finish Date 370Activities with Lags 370Activities with Constraints 371Activities with Different Calendars 373Precedence Diagrams 373Further Discussion of Example 7 375Resource Constraints 377Resource Allocation and Resource Leveling 378Risk and Probabilistic Durations 379Risk, Consequences, or Both? 379The AACE Recommended Practices No. 49R-06 and 92R-17 381Proposed Definition of the Critical Path 381Changes in the Critical Path 382Chapter 14 Construction Delays and Other Claims 383Introduction 384Delay Claims 384Reasons for Claims 386Force Majeure 388Types of Delays 389Scheduling Mistakes Related to Delay Claims 390Project Documentation 393Delay Claims Resolution 396The Importance of CPM Schedules in Delay Claims 399Methods of Schedule Analysis 399As-built Schedule 400Updated Impact Schedule 400As-Planned Schedule 400Comparison Schedule 400Accelerated Schedule 400Who Owns the Float 401Chapter 14 Exercises 406Chapter 15 Schedule Risk Management 409Introduction 410Types of Risk in Construction Projects 411Schedule Risk Types 412General Duration Uncertainty 414Specific Risk Events 416Network Logic Risks 417Definition of Risk Terms 418Importance of Good Planning for Risk Management 420Importance of Good CPM Scheduling Practices for Risk Assessment 420Risk Shifting in Contracts 422Schedule Risk Management Steps 4241. Risk Management Planning 4252. Identifying Schedule Risks 4273. Performing Qualitative Analysis 4274. Performing Risk Prioritization for the Qualitative Analysis (Quantitative Analysis) 4295. Responding to and Addressing Risks 4296. Monitoring and Updating the Risk Management Plan 430Expected Value 430Application in Scheduling 432Examples of Risk Adjustment 433Conclusion 434Chapter 15 Exercises 435Chapter 16 BIM-Based 4D Modeling and Scheduling 437Overview of Building Information Modeling (BIM) 437Definition and Benefits of BIM 437Differences between BIM and CAD 438Definition and Benefits of 3D Modeling 440Definition and Benefits of 4D Modeling 441Steps for Creating 4D Models 442Definition and Benefits of 5D Modeling 443Case Study 445Project Information 445Creating and Linking the 3D Model 445Information about the TimeLiner Tab 446Creating and Importing Project Schedules 447Defining Task Types 451Creating Selection Sets 453Creating the 4D Model and Project Animation 453Exporting Snapshots and Animation 457Using Integrated Systems 461Lean Construction 462Chapter 16 Exercises 464Chapter 17 Project Scheduling for Owners 467Introduction 467Project Initiation Process 468The Owner’s Organization 471Project Planning 471Using Available Tools 473Best Value 473The Evolution of the Schedule 474Choosing the Contract Type and Delivery Method 475Contract Templates 476Owner-Contractor Trust Relationship 477Project Financing 477Requiring and Approving a Schedule 478Owning and Managing Float 479Managing the Contractor 480Managing Scope/Changes 480Schedule Updating and Percent Complete 482Delay Claims: Avoidance and Resolution 482Chapter 17 Exercises 483Appendix A Computer Project 485General Guidelines 485Assignment 1 488Cost Loading 489Assignment 2 491Updating the Project 491Assignment 3 492Change Order 492Assignment 4 493Resource Leveling 493Assignment 5 493Schedule Compression 1 494Assignment 6 494Schedule Compression 2 496Assignment 7 496Delay Claim 1: Unforeseen Conditions 496Assignment 8 497Delay Claim 2: Change in the Owner’s Requirements 497Assignment 9 497Appendix B Sample Reports 499Tabular Reports 499Graphic Reports 517Abbreviations 529Glossary 535Bibliography 559Index 567