Page 213 - Forensic Structural Engineering Handbook

THE ENGINEERING INVESTIGATION PROCESS 6.15

FIGURE 6.11 Each of these structures complied with the governing design code at the time it
was constructed. The structure in the background was designed based upon more stringent crite-
ria in a later code, which enabled it to survive the hurricane.

TABLE 6.7 Common Laboratory Techniques

Metals
Basic mechanical properties Yield and tensile strength, elongation, reduction of area, modulus of
elasticity, fatigue properties
Fractography Failure analysis of fracture surface, usually with optical or scanning
electron microscope
Fracture toughness Charpy V-notch, fracture toughness, nil-ductility transition
temperature
Welding Radiography, visual, dye penetrant, ultrasonic, magnetic particle,
eddy current, metallography
Hardness tests Brinell, Rockwell, Vickers, and Knoop
Metallurgy and quantitative Chemical composition, grain analysis, phase-type, flaw detection
analysis
Concrete
Basic mechanical properties Compressive strength, tensile strength, shear strength, modulus of
elasticity, density, bond strength, fatigue strength, abrasion resistance
Dimensional stability Creep and shrinkage, coefficient of thermal expansion
Petrographic analysis Quantitative analysis, air content, degree of hydration and
carbonation, alkali-carbonate reaction, alkali-silica reaction, cement
aggregate reaction, cement content, soundness, water/cement ratio,
sulfate attack
Corrosion and durability Permeability, half-cell potential
Wood
Basic mechanical properties Tensile, shear, compressive, and bearing strength; modulus of
elasticity; density
Dimensional stability Creep and shrinkage, moisture content
Presence of decay Microscopic inspection