Pedestrian Fall Safety Assessments (eBook)

Dr In-Ju Kim is an Assistant Professor in the Department of Industrial Engineering and Engineering Management at the University of Sharjah, United Arab Emirates.He received his Ph.D. degree from the University of Sydney, Australia. After earning a Ph.D. degree, he has worked for broad areas of Ergonomics, Human Factors, Industry and Occupational Safety and Health, Applied Biomechanics, and Sports Engineering and Technology through a number of research and industry projects from Australia, the UK, the USA, and Saudi Arabia over the last fifteen years.He is an active researcher in the fields of industry and occupational safety, ergonomics/human factors engineering, biomechanics, injury prevention, sports engineering, and rehabilitation science and technology. He also has served as an editor and editorial board member of four journals in the disciplinary areas of Industrial Engineering, Safety Science and Technology, and Rehabilitation Science and Technology.div>

Foreword I 6
Foreword II 8
Preface 9
Background and Motivation 9
Main Aims of This Book 10
Construction of This Book 10
Final Remarks 15
Contents 16
Glossary Terms, Abbreviations and Acronyms 21
List of Figures 24
List of Tables 29
1 Introduction 31
1.1 Backgrounds 31
1.2 Major Issues on Slip Resistance Measurements 34
1.3 Surface Finishes Versus Slip Resistance Performance 36
1.4 Wear Development Versus Slip Resistance Performance 36
1.5 Optimal Floor Surface Finishes 38
1.6 Major Significances and Contributions 38
1.7 Specific Aims 39
1.8 Limitations 40
1.9 Summary 41
References 42
2 Pedestrian Fall Incidence and Slip Resistance Measurements 46
2.1 Brief Overview of Slip and Fall Incidences 46
2.2 Injuries Owing to Slips and Falls 47
2.3 Improvements of Fall Prevention 48
2.4 Factors Influencing Pedestrian Fall Incidence 49
2.4.1 Intrinsic Fall Risk Factors 50
2.4.2 Extrinsic Fall Risk Factors 51
2.4.3 Mechanics of Human Walking 51
2.5 Human Gait and Its Impacts on Fall Incidents 52
2.6 Observation of Human Gait 54
2.7 Gait Analysis and Fall Risk Prediction 55
2.8 Measuring Devices for Slip Resistance Properties 57
2.8.1 Articulated Strut Devices 57
2.8.2 Drag and Towed-Sled Devices 57
2.8.3 Pendulum Type Devices 60
2.8.4 Other Type Devices 60
2.8.5 Slip Measuring Testers Used in This Book 63
2.8.6 Comparisons of Slip Measuring Devices 66
2.9 Testing Standards and Safety Criteria for Slip Resistance Performance 68
2.9.1 Slip Resistance Test Methods and Safety Criteria 68
2.9.1.1 The Pendulum Slip Resistance Tester 69
2.9.1.2 Tortus Digital Tribometer 70
2.9.1.3 BOT 3000 Slip Tester 71
2.9.1.4 Variable Angle Ramp 73
2.9.1.5 SlipAlert Slip Tester 74
2.9.2 Undependable Test Methods and Removed Standards 75
2.9.2.1 ASTM C1028-07 75
2.9.2.2 Brungraber Mark II (PIAST) and English XL (VIT) Tribometers 75
2.9.3 Clean and Dry and Wet Slip Resistance Measurements 76
2.9.3.1 Importance of Dry Slip Resistance Measurement 76
2.9.3.2 The Sine Qua Non for Slip Safety Assessments 77
2.10 Relationships Between Human Gait and Slip Resistance Properties 79
2.11 Chapter Summary 83
References 84
3 Pedestrian Slip Resistance Measurements: Verities and Challenges 95
3.1 Introduction 95
3.2 Brief Overview 96
3.3 Theoretical Backgrounds 98
3.4 Mislead Issues on Slip Resistance Measurements 100
3.5 Definition of a COF 101
3.6 Friction Development Between Two Solid Surfaces 103
3.7 What Does a COF Quantity Mean?—Misconception and Restraint 107
3.8 A Concept of Average COF—Case Study No. 1 108
3.9 A Concept of Average COF—Case Study No. 2 110
3.10 Issues of Frictional Force and Heel Strike Angle 112
3.10.1 Frictional Force 112
3.10.2 Heel Strike Angle 115
3.11 Maintenance Issues 116
3.12 Conclusions 117
3.13 Chapter Summary 118
References 119
4 Tribological Approaches for the Pedestrian Safety Measurements and Assessments 123
4.1 Introduction 123
4.2 Tribo-Physical Approaches 123
4.2.1 Overview 123
4.2.2 Limitations and Issues 124
4.2.3 Main Problems 128
4.3 Studies on Surface Roughness Measurements 130
4.3.1 Background 130
4.3.2 Measuring Devices for Surface Roughness 132
4.4 Understanding of the Shoe-Floor Sliding Friction Interface 134
4.4.1 Significance of Friction Process 135
4.4.2 Measuring Slipperiness 135
4.4.3 Measuring Devices for Slip Resistance 136
4.5 Basic Tribology for the Shoe-Floor Sliding Friction Mechanism 137
4.5.1 Pedestrian Slip Resistance Requirements 137
4.5.2 Shoe-Floor Friction and COF Measurements 137
4.5.3 Function of Shoes on Slip Resistance 138
4.5.4 Function of Floors on Slip Resistance 138
4.5.5 Factors Affecting Film Formations 139
4.6 Slip Resistance Measurement and Reaction 140
4.7 Conflict over Slip Resistance, Hygiene, and Maintenance 141
4.8 Chapter Summary 142
References 142
5 Friction and Wear Mechanisms 148
5.1 Introduction 148
5.2 Friction Mechanism 149
5.2.1 Definition of Friction 149
5.2.2 The Laws of Friction 150
5.2.3 The Origins of Friction 153
5.2.3.1 Introduction 153
5.2.3.2 The Amonton’s Laws 153
5.2.3.3 Sliding Friction 154
5.2.3.4 Adhesion Force 155
Simple Adhesion Theory 155
Extension of Simple Adhesion Theory 157
5.2.3.5 Deformation Force 157
Deformation 157
Deformation Theories 158
5.3 Friction Mechanism at the Shoe-Floor Sliding Interface 160
5.3.1 Introduction 160
5.3.2 Adhesion Component 161
5.3.3 Deformation Component 164
5.4 Wear Mechanism 166
5.4.1 Introduction 166
5.4.2 Main Considerations 166
5.5 Wear Model for the Shoe-Floor Sliding Friction System 168
5.6 Chapter Summary 171
References 172
6 Surface Measurement and Analysis 176
6.1 Introduction 176
6.2 Nature of Surfaces and Their Contact Mechanism 177
6.2.1 Fundamental Concepts 177
6.2.2 Contact Mechanism Between Two Surfaces 178
6.2.3 Simple Theory of Rough Surface Contact 179
6.2.4 Statistical Theories of Rough Surface Contact 182
6.3 Some Geometrical Properties of Surface Texture 184
6.3.1 Introduction 184
6.3.2 Surface Texture 184
6.4 Measurement of Surface Topography 187
6.4.1 Surface Texture Analysis 187
6.4.2 Surface Profilometry 187
6.4.3 Laser Scanning Confocal Microscope 192
6.4.3.1 Introduction 192
6.4.3.2 The Principles of Confocal Imaging 192
6.4.3.3 Laser Scanning Confocal Microscope (LSCM) 195
6.5 Importance of Surface Analysis for Slip Resistance Assessment 196
6.6 Effects of Surface Roughness on Slip Resistance Performance 197
6.7 Quantifying Surface Roughness 198
6.7.1 Introduction 198
6.7.2 Measuring Lengths 199
6.7.3 Reference Line 199
6.7.4 Traditional Surface Roughness Parameters 200
6.8 Statistical Analysis of Surface Finishes 201
6.8.1 Background 201
6.8.2 Statistical Analysis of Surface Roughness 202
6.8.3 Height Distribution of Surface Texture 202
6.8.3.1 CLA and RMS Roughness 203
6.8.3.2 Extreme Value Roughness Parameters 205
6.8.3.3 Shape Parameters 207
6.8.4 Spatial Distribution of Surface Texture 209
6.8.4.1 Average Wavelength 209
6.8.4.2 RMS Wavelength 210
6.8.4.3 High Spot Count (HSC) 210
6.8.5 Hybrid Parameters 210
6.8.5.1 Mean Slope (?a and ?q) 211
6.9 Relationships Amongst Surface Roughness Parameters 212
6.10 Surface Analysis for the Shoe-Floor Friction System 213
6.11 Development of a Contact Model Between the Shoe and Floor Surface 214
6.11.1 Introduction 214
6.11.2 Main Hypotheses for Contact Model Development 215
6.11.3 Model Development 217
6.11.3.1 Consideration of Normal Loading 218
6.11.3.2 Consideration of Frictional (or Tangential) Loading 219
6.12 Conclusions 219
6.13 Chapter Summary 220
References 221
7 A Practical Design Search for Optimal Floor Surface Finishes—A Case Study 226
7.1 Introduction 226
7.2 Theory Development 228
7.2.1 Main Hypothesis 228
7.2.2 A Floor-Surface Model for Optimal Operational Levels 229
7.3 A Case Study—Experimental Methods and Materials 230
7.3.1 Dynamic Friction Tester 230
7.3.2 Test System Conditions 232
7.3.2.1 Test Speed 232
7.3.2.2 Contact Angle 233
7.3.2.3 Normal Force 233
7.3.2.4 Dynamic Friction Test Output 233
7.3.3 Floor and Shoe Specimens 234
7.3.4 Environmental Conditions 235
7.3.5 Floor Surface Roughness Measurements 235
7.3.6 Statistical Analysis and Design 235
7.4 Results of the Case Study 236
7.4.1 Slip Resistance Performance 236
7.4.2 Interactions Between Floor Types and Environments 236
7.4.3 Interactions Between Shoe Types and Environments 239
7.4.4 Operational Ranges of Floor Surface Roughness 240
7.5 Assessments and Verifications of Findings 244
7.5.1 Interactions Between Floor Types and Environments 244
7.5.2 Interactions Between Shoe Types and Environments 245
7.5.3 Operational Ranges of Floor Surface Roughness 245
7.6 Study Limitations 246
7.7 Conclusions 247
7.8 Chapter Summary 247
References 248
8 Future Works 252
8.1 Introduction 252
8.2 Review of Overall Aims 253
8.3 Recommendations for the Future Studies 254
8.3.1 Necessary Advancements in the Tribo-physical Model 254
8.3.2 Long Term Plan for the Tribo-physical Model 255
8.3.3 Improvement for Slip Measuring Concepts 255
8.4 Conclusions 257
Reference 257
Index 258