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 xiii

Preface to the First Edition xvii

Chapter 1 Introduction 1

Planning and Scheduling 2

What is a Project? 2

Are Projects Unique? 4

Project Management Plan 7

Project Control 8

Why Schedule Projects? 8

The Scheduler 11

Certification 11

The Tripod of a Good Scheduling System 12

Scheduling and Project Management 12

Chapter 1 Exercises 13

Chapter 2 Bar (Gantt) Charts 15

Definition and Introduction 16

Advantages of Bar Charts 18

Disadvantages of Bar Charts 20

Chapter 2 Exercises 21

Chapter 3 Basic Networks 23

Definition and Introduction 24

Arrow Networks 24

Brief Explanation 24

The Logic 25

Notation 25

Dummy Activities 26

Redundancies 31

Node Networks 31

Lags and Leads 32

Recommendations for Proper Node Diagram Drawing 35

Comparison of Arrow and Node Networks 37

Networks versus Bar Charts 39

Effective Use of Bar Charts with CPM 40

Time-Scaled Logic Diagrams 40

Chapter 3 Exercises 41

Chapter 4 The Critical Path Method (CPM) 45

Introduction 46

Steps Required to Schedule a Project 47

Main Steps 47

Supplemental Steps 55

Resource Allocation and Leveling 57

Beginning-of-Day or End-of-Day Convention 59

The CPM Explained through Examples 59

Example 4.1: Logic Networks and the CPM 59

The CPM with Computer Software Programs 63

The Critical Path 64

Definitions 65

Examples 4.2 and 4.3: Node Diagrams and the CPM 66

Free Float 67

More Definitions 70

Float Check 71

Node Format 72

Lags and Leads in CPM Networks 73

Lags and Leads in Computer Software 76

Further Discussion of Float 76

Effect of Date Choices on Cash Flow 78

Project Schedule “Health Check” 78

Event Times in Arrow Networks 79

Effect of the Imposed Finish Date on the Schedule 81

Discussion of Example 4.7 82

Logic and Constraints 84

The “Hub” Concept 85

The Critical Path Method and Scheduling 85

Chapter 4 Exercises 86

Chapter 5 Precedence Networks 93

Definition and Introduction 94

The Four Types of Relationships 97

Important Comments about the Four Types of Relationships 98

The Percent Complete Approach 98

Fast-Track Projects 99

A Parallel Predecessor? 101

CPM Calculations for Precedence Diagrams 102

Interruptible Activities 102

The Simplistic Approach 105

Alternative Approach 107

The Detailed Approach 110

Contiguous (Uninterruptible) Activities 113

Remedy for Interruptible Activities 117

Multistage Activities 120

Types of Lags 121

Final Discussion 123

Chapter 5 Exercises 124

Chapter 6 Resource Allocation and Resource Leveling 129

Introduction 130

The Three Categories of Resources 130

Labor 130

Equipment and Materials 130

What is Resource Allocation? 131

Resource Leveling 131

What is Resource Leveling? 131

Why Level Resources? 131

Do All Resources Have to Be Leveled? 132

Multiproject Resource Leveling 132

Assigning Budgets in Computer Scheduling Programs 134

Leveling Resources in a Project 136

Resource Leveling from the General Contractor’s Perspective 153

Materials Management 155

Chapter 6 Exercises 159

Chapter 7 Schedule Updating and Project Control 163

Introduction 164

The Need for Schedule Updating 164

Project Control Defined 164

Schedule Updating 165

What is a Baseline Schedule? 165

What is an Updated Schedule? 167

What is the Data Date? 168

What Kind of Information is Needed for Updating Schedules? 168

Frequency of Updating 171

Retained Logic or Progress Override 172

Auto-Updating 172

Updating Schedules and Pay Requests 173

“Degressing” an In-Progress Schedule to Create a Baseline Schedule 175

Effect of Adding or Deleting Activities on Logic 176

Steps for Updating a Schedule 180

Change in the Critical Path 191

Float after the Update 191

Contractor-Created Float 192

Data and Information 193

Project Control 194

Measuring Work Progress 194

Earned Value Analysis 208

Chapter 7 Exercises 217

Chapter 8 Schedule Compression and Time-Cost Trade-Off 223

Introduction 224

How Important is It to Finish on Schedule? 225

Setting Priorities 225

Accelerating a Project 226

What is “Accelerating” a Project? 226

Why Accelerate a Project? 226

How Can Project Duration Be Shortened? 227

Acceleration and Fast-Tracking 235

Construction and Modularization 235

How Does Accelerating a Project Work? 236

Direct and Indirect Costs 238

Cost Concepts as They Relate to Schedule Compression 240

Choosing the Best Method for Project Acceleration 240

Effect of Acceleration on Direct Costs 241

Effect of Acceleration on Indirect Costs 242

Effect of Acceleration on Total Cost 243

Issues to Consider When Accelerating a Project 245

Recovery Schedules 247

Accelerating Projects Using Computers 252

Potential Issues with Uncoordinated Project Acceleration 253

Optimum Project Scheduling 254

Project Scheduling and Prevailing Economic Conditions 255

Project Scheduling in Extreme Weather Regions 256

Optimum Scheduling 256

Productivity and Cost Multipliers 258

Chapter 8 Exercises 260

Chapter 9 Reports and Presentations 265

Introduction 266

The Difference between Reports and Presentations 270

Skills Necessary for Giving Good Presentations 272

The Power of Presentations 273

Reviewing Reports before and after Printing 275

General Tips on Printing Reports 276

Summary Reports 277

Paper or Electronic Reports? 277

E-Reports 280

Communications in the International Environment 280

Chapter 9 Exercises 282

Chapter 10 Scheduling as Part of the Project Management Effort 285

Introduction 286

Project Objectives 287

Defining and Measuring Project Success 288

Scheduling and Estimating 290

Evolution of a Cost Estimate and a Schedule for a Project 291

Estimate-Generated Schedules 294

Cost-Loaded Schedules 296

Estimating and Accounting 296

Scheduling and Accounting 298

Scheduling and Change Orders 298

Paperless Project Management 299

Procurement Management 300

Management of Submittals 301

The Master Schedule and Subschedules 303

Multiproject Management 304

Time Contingency and Management Options 305

Chapter 10 Exercises 308

Chapter 11 Other Scheduling Methods 311

Introduction 312

Program Evaluation and Review Technique (PERT) 312

Background 312

Concept of PERT 312

How PERT Works 313

PERT Calculations 313

Graphic Explanation 316

“Most Likely” versus “Expected” Durations 323

Is the Longest Path Still the Most Critical? 323

Using PERT to Calculate the Date of an Event with a Certain Level of Confidence 326

Determining the Probability of a Certain Project Finish Date (Multiple Paths Considered) 327

PERT and the Construction Industry 328

PERT and Computer Project-Scheduling Software 328

Graphical Evaluation and Review Technique (GERT) 329

Linear Scheduling Method (LSM) 330

Steps to Build a Schedule Using the LSM 331

How the LSM Works 331

LSM and Project Schedule Acceleration 337

LSM Computer Software Programs 337

Graphical Path Method (GPM) 338

Relationship Diagramming Method (RDM) 342

The Critical Path Segments (CPS) Scheduling Technique 346

Chapter 11 Exercises 348

Chapter 12 Dynamic Minimum Lag Relationship 353

Introduction 354

Why DML? 354

Similarity between the DML Concept and the Linear Scheduling Method (LSM) 355

How Does DML Work? 356

DML Relationship in CPM Calculations 358

Can the Lag in the DML Relationship Be a Percentage? 359

Conclusion 365

Chapter 12 Exercises 366

Chapter 13 The Critical Path Definition: Revisited 367

Introduction 367

What is the “Longest Path”? 368

The Critical Path through Examples 369

The Simple Case 369

Imposed Finish Date 370

Activities with Lags 370

Activities with Constraints 371

Activities with Different Calendars 373

Precedence Diagrams 373

Further Discussion of Example 7 375

Resource Constraints 377

Resource Allocation and Resource Leveling 378

Risk and Probabilistic Durations 379

Risk, Consequences, or Both? 379

The AACE Recommended Practices No. 49R-06 and 92R-17 381

Proposed Definition of the Critical Path 381

Changes in the Critical Path 382

Chapter 14 Construction Delays and Other Claims 383

Introduction 384

Delay Claims 384

Reasons for Claims 386

Force Majeure 388

Types of Delays 389

Scheduling Mistakes Related to Delay Claims 390

Project Documentation 393

Delay Claims Resolution 396

The Importance of CPM Schedules in Delay Claims 399

Methods of Schedule Analysis 399

As-built Schedule 400

Updated Impact Schedule 400

As-Planned Schedule 400

Comparison Schedule 400

Accelerated Schedule 400

Who Owns the Float 401

Chapter 14 Exercises 406

Chapter 15 Schedule Risk Management 409

Introduction 410

Types of Risk in Construction Projects 411

Schedule Risk Types 412

General Duration Uncertainty 414

Specific Risk Events 416

Network Logic Risks 417

Definition of Risk Terms 418

Importance of Good Planning for Risk Management 420

Importance of Good CPM Scheduling Practices for Risk Assessment 420

Risk Shifting in Contracts 422

Schedule Risk Management Steps 424

1. Risk Management Planning 425

2. Identifying Schedule Risks 427

3. Performing Qualitative Analysis 427

4. Performing Risk Prioritization for the Qualitative Analysis (Quantitative Analysis) 429

5. Responding to and Addressing Risks 429

6. Monitoring and Updating the Risk Management Plan 430

Expected Value 430

Application in Scheduling 432

Examples of Risk Adjustment 433

Conclusion 434

Chapter 15 Exercises 435

Chapter 16 BIM-Based 4D Modeling and Scheduling 437

Overview of Building Information Modeling (BIM) 437

Definition and Benefits of BIM 437

Differences between BIM and CAD 438

Definition and Benefits of 3D Modeling 440

Definition and Benefits of 4D Modeling 441

Steps for Creating 4D Models 442

Definition and Benefits of 5D Modeling 443

Case Study 445

Project Information 445

Creating and Linking the 3D Model 445

Information about the TimeLiner Tab 446

Creating and Importing Project Schedules 447

Defining Task Types 451

Creating Selection Sets 453

Creating the 4D Model and Project Animation 453

Exporting Snapshots and Animation 457

Using Integrated Systems 461

Lean Construction 462

Chapter 16 Exercises 464

Chapter 17 Project Scheduling for Owners 467

Introduction 467

Project Initiation Process 468

The Owner’s Organization 471

Project Planning 471

Using Available Tools 473

Best Value 473

The Evolution of the Schedule 474

Choosing the Contract Type and Delivery Method 475

Contract Templates 476

Owner-Contractor Trust Relationship 477

Project Financing 477

Requiring and Approving a Schedule 478

Owning and Managing Float 479

Managing the Contractor 480

Managing Scope/Changes 480

Schedule Updating and Percent Complete 482

Delay Claims: Avoidance and Resolution 482

Chapter 17 Exercises 483

Appendix A Computer Project 485

General Guidelines 485

Assignment 1 488

Cost Loading 489

Assignment 2 491

Updating the Project 491

Assignment 3 492

Change Order 492

Assignment 4 493

Resource Leveling 493

Assignment 5 493

Schedule Compression 1 494

Assignment 6 494

Schedule Compression 2 496

Assignment 7 496

Delay Claim 1: Unforeseen Conditions 496

Assignment 8 497

Delay Claim 2: Change in the Owner’s Requirements 497

Assignment 9 497

Appendix B Sample Reports 499

Tabular Reports 499

Graphic Reports 517

Abbreviations 529

Glossary 535

Bibliography 559

Index 567