|Topics||Bridge Forms, Ceramics, Force Lines of Action, Modulus of Elasticity, Specific Gravity|
The six basic bridge forms are beam, truss, arch, cantilever, cable, and suspension.
Ceramics are mixtures of metallic and nonmetallic elements that withstand exteme thermal, chemical, and pressure environments. They have a high melting point, low corrosive action, and are chemically stable. Examples include rock, sand, clay, glass, brick, and porcelain.
Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.
The modulus of elasticity measures how much a material or structure will deflect under stress. Stretch modulus is longitudinal stretch (like stretching raw bread dough), shear modulus is longitudinal deflection (like the horizontal displacement of a stack of magzines when a heavy object is placed upon them), and bulk modulus is compression of volume (like the compression of a loaf of bread under a heavy can at the bottom of a grocery bag).
Specific gravity is the ratio of the density of equal volumes of a substance and water and is measured by a hyrdometer.