Forensic engineering investigation

2 Investigation Pyramid 3 -- 1.3 Eyewitness Information 6 -- 1.4 Role in the Legal System 8 -- 1.5 Scientific Method 9 -- 1.6 Applying the Scientific Method to Forensic Engineering 10 -- 1.7 Scientific Method and the Legal System 12 -- 1.8 A Priori Biases 13 -- 1.9 Engineer as Expert Witness 14 -- 1.10 Reporting the Results of a Forensic Engineering Investigation 16 -- 2 Wind Damage to Residential Structures 23 -- 2.1 Code Requirements for Wind Resistance 23 -- 2.2 Some Basics about Wind 26 -- 2.3 Variation of Wind Speed with Height 32 -- 2.4 Estimating Wind Speed from Localized Damages 33 -- 2.5 Additional Remarks 34 -- 3 Lightning Damage to Well Pumps 37 -- 3.1 Correlation is Not Causation 37 -- 3.2 Converse of Coincidence Argument 38 -- 3.3 Underlying Reasons for Presuming Cause and Effect 39 -- 3.4 A Little about Well Pumps 40 -- 3.5 Lightning Access to a Well Pump 40 -- 3.6 Well Pump Failures 43 -- 3.7 Failure Due to Lightning 44 -- 4 Evaluating Blasting Damage 47 -- 4.1 Pre-Blast and Post-Blast Surveys 47 -- 4.2 Effective Surveys 49 -- 4.3 Types of Damages Caused by Blasting 50 -- 4.4 Flyrock Damage 51 -- 4.5 Surface Blast Craters 53 -- 4.6 Air Concussion Damage 54 -- 4.7 Air Shock Wave Damage 57 -- 4.8 Ground Vibrations 58 -- 4.9 Blast Monitoring with Seismographs 59 -- 4.10 Blasting Study by U.S. Bureau of Mines, Bulletin 442 60 -- 4.11 Blasting Study by U.S. Bureau of Mines, Bulletin 656 61 -- 4.12 Safe Blasting Formula from Bulletin 656 62 -- 4.13 OSM Modifications of the Safe Blasting Formula in Bulletin 656 63 -- 4.14 Human Perception of Blasting Noise and Vibrations 64 -- 4.15 Damages Typical of Blasting 66 -- 4.16 Types of Damage Often Mistakenly Attributed to Blasting 69 -- 4.17 Continuity 72 -- 5 Building Collapse Due to Roof Leakage 75 -- 5.1 Typical Commercial Buildings 1877-1917 75 -- 5.2 Lime Mortar 77 -- 5.3 Roof Leaks 80 -- 5.4 Deferred Maintenance Business Strategy 80 -- 5.5 Structural Damage Due to Roof Leaks 82 -- 5.6 Structural Considerations 84 -- 5.7 Restoration Efforts 87 -- 6 Putting Machines and People Together 89 -- 6.1 Some Background 89 -- 6.2 Vision 92 -- 6.3 Sound 93 -- 6.4 Sequencing 95 -- 6.5 Audi 5000 Example 95 -- 6.6 Guarding 97 -- 6.7 Employer's Responsibilities 99 -- 6.8 Manufacturer's Responsibilities 100 -- 6.9 New Ergonomic Challenges 101 -- 7 Determining the Point of Origin of a Fire 103 -- 7.2 Burning Velocities and "V" Patterns 104 -- 7.3 Burning Velocities and Flame Velocities 107 -- 7.4 Flame Spread Ratings of Materials 110 -- 7.5 A Little Heat Transfer Theory: Conduction and Convection 114 -- 7.6 Radiation 118 -- 7.7 Initial Reconnoiter of the Fire Scene 122 -- 7.8 Centroid Method 124 -- 7.9 Ignition Sources 125 -- 7.10 Warehouse or Box Method 127 -- 7.11 Weighted Centroid Method 128 -- 7.12 Fire Spread Indicators--Sequential Analysis 130 -- 7.13 Combination of Methods 133 -- 8 Electrical Shorting 135 -- 8.2 Thermodynamics of a "Simple Resistive" Circuit 138 -- 8.3 Parallel Short Circuits 146 -- 8.4 Series Short Circuits 149 -- 8.5 Beading 152 -- 8.6 Fuses, Breakers, and Overcurrent Protection 156 -- 8.7 Example Situation Involving Overcurrent Protection 161 -- 8.8 Ground Fault Circuit Interrupters 162 -- 8.9 "Grandfathering" of GFCIs 163 -- 8.10 Other Devices 163 -- 8.11 Lightning Type Surges 165 -- 8.12 Common Places Where Shorting Occurs 165 -- 9 Explosions 175 -- 9.2 High Pressure Gas Expansion Explosions 177 -- 9.3 Deflagrations and Detonations 178 -- 9.4 Some Basic Parameters 182 -- 9.5 Overpressure Front 185 -- 10 Determining the Point of Ignition of an Explosion 191 -- 10.2 Diffusion and Fick's Law 192 -- 10.3 Flame Fronts and Fire Vectors 194 -- 10.4 Pressure Vectors 195 -- 10.52 Epicenter 196 -- 10.6 Energy Considerations 197 -- 11 Arson and Incendiary Fires 201 -- 11.2 Arsonist Profile 203 -- 11.3 Basic Problems of Committing an Arson for Profit 204 -- 11.4 Prisoner's Dilemma 206 -- 11.5 Typical Characteristics of an Arson or Incendiary Fire 207 -- 11.6 Daisy Chains and Other Arson Precursors 209 -- 11.7 Arson Reporting Immunity Laws 211 -- 11.8 Liquid Accelerant Pour Patterns 212 -- 11.9 Spalling 214 -- 11.10 Detecting Accelerants after a Fire 218 -- 12 Simple Skids 223 -- 12.2 Basic Equations 223 -- 12.3 Simple Skids 224 -- 12.4 Tire Friction 226 -- 12.5 Multiple Surfaces 227 -- 12.6 Calculation of Skid Deceleration 229 -- 12.7 Speed Reduction by Skidding 229 -- 12.8 Some Considerations of Data Error 229 -- 12.9 Curved Skids 230 -- 12.10 Brake Failures 231 -- 12.11 Changes in Elevation 233 -- 12.12 Load Shift 235 -- 12.13 Antilock Brake Systems (ABS) 236 -- 13 Simple Vehicular Falls 239 -- 13.2 Basic Equations 239 -- 13.3 Ramp Effects 241 -- 13.4 Air Resistance 244 -- 14 Vehicle Performance 247 -- 14.2 Engine Limitations 247 -- 14.3 Deviations from Theoretical Model 251 -- 14.4 Example Vehicle Analysis 252 -- 14.5 Braking 253 -- 14.6 Stuck Accelerators 254 -- 14.7 Brakes vs. the Engine 255 -- 14.8 Power Brakes 257 -- 14.9 Linkage Problems 258 -- 14.10 Cruise Control 258 -- 14.11 Transmission Problems 259 -- 14.12 Miscellaneous Problems 260 -- 14.13 NHTSA Study 260 -- 14.14 Maximum Climb 261 -- 14.15 Estimating Transmission Efficiency 263 -- 14.16 Estimating Engine Thermal Efficiency 265 -- 14.17 Peel-Out 265 -- 14.18 Lateral Tire Friction 266 -- 14.19 Bootlegger's Turn 266 -- 15 Momentum Methods 271 -- 15.2 Basic Momentum Equations 272 -- 15.3 Properties of an Elastic Collision 273 -- 15.4 Coefficient of Restitution 275 -- 15.5 Properties of a Plastic Collision 276 -- 15.6 Analysis of Forces during a Fixed Barrier Impact 278 -- 15.7 Energy Losses and "[varepsilon]" 279 -- 15.8 Center of Gravity 281 -- 15.9 Moment of Inertia 283 -- 15.10 Torque 285 -- 15.11 Angular Momentum Equations 287 -- 15.12 Solution of Velocities Using the Coefficient of Restitution 288 -- 15.13 Estimation of a Collision Coefficient of Restitution from Fixed Barrier Data 291 -- 15.14 Discussion of Coefficient of Restitution Methods 293 -- 16 Energy Methods 295 -- 16.2 Some Theoretical Underpinnings 297 -- 16.3 General Types of Irreversible Work 303 -- 16.4 Rollovers 304 -- 16.5 Flips 310 -- 16.6 Modeling Vehicular Crush 316 -- 16.7 Post-Buckling Behavior of Columns 318 -- 16.8 Going from Soda Cans to the Old 'Can You Drive?' 320 -- 16.9 Evaluation of Actual Crash Data 322 -- 16.10 Low Velocity Impacts--Accounting for the Elastic Component 323 -- 16.11 Representative Stiffness Coefficients 324 -- 16.12 Some Additional Comments 326 -- 17 Curves and Turns 329 -- 17.1 Transverse Sliding on a Curve 329 -- 17.2 Turnovers 333 -- 17.3 Load Shifting 334 -- 17.4 Side vs. Longitudinal Friction 335 -- 17.5 Cornering and Side Slip 336 -- 17.6 Turning Resistance 337 -- 17.7 Turning Radius 338 -- 17.8 Measuring Roadway Curvature 339 -- 17.9 Motorcycle Turns 340 -- 18 Visual Perception and Motorcycle Accidents 343 -- 18.2 Background Information 344 -- 18.3 Headlight Perception 345 -- 18.4 Daylight Perception 347 -- 18.5 Review of the Factors in Common 348 -- 18.6 Difficulty Finding a Solution 349 -- 19 Interpreting Lamp Filament Damages 351 -- 19.2 Filaments 351 -- 19.3 Oxidation of Tungsten 353 -- 19.4 Brittleness in Tungsten 355 -- 19.5 Ductility in Tungsten 355 -- 19.6 Turn Signals 357 -- 19.7 Other Applications 357 -- 19.8 Melted Glass 357 -- 19.9 Sources of Error 358 -- 20 Automotive Fires 361 -- 20.2 Vehicle Arson and Incendiary Fires 362 -- 20.3 Fuel-Related Fires 364 -- 20.4 Other Fire Loads under the Hood 368 -- 20.5 Electrical Fires 368 -- 20.6 Mechanical and Other Causes 370 -- 21 Hail Damage 373 -- 21.2 Hail Size 375 -- 21.3 Hail Frequency 378 -- 21.4 Hail Damage Fundamentals 380 -- 21.5 Size Threshold for Hail Damage to Roofs 384 -- 21.6 Assessing Hail Damage 387 -- 21.7 Cosmetic Hail Damage--Burnish Marks 395 -- 21.8 Haig Report 398 -- 21.9 Damage to the Sheet Metal of Automobiles and Buildings 401 -- 21.10 Foam Roofing Systems 404 -- 22 Blaming Brick Freeze-Thaw Deterioration on Hail 407 -- 22.1 Some General Information about Bricks 407 -- 22.2 Brick Grades 408 -- 22.3 Basic Problem 409 -- 22.4 Experiment 410 -- 23 Management's Role in Accidents and Catastrophic Events 413 -- 23.2 Human Error vs. Working Conditions 417 -- 23.3 Job Abilities vs. Job Demands 417 -- 23.4 Management's Role in the Causation of Accidents and Catastrophic Even