PSAD Terms - CE Board Exam Refresher

Vocabulary flashcards covering key Structural Engineering and Mechanics terms for Civil Engineering Board Exam preparation.

Bearing stress

The compressive pressure between two bodies that are pressed against each other.

Strain

Deformation per unit length.

Poisson's ratio

The ratio of lateral strain to longitudinal strain used to determine lateral deformation when a material elongates.

Rigidity

A body's resistance to deformation.

Stiffness

A member's resistance to deformation relative to its length, taken as the amount of force required to produce unit deformation; also defined as the inverse of flexibility.

Hooke's Law

The law stating that up to the proportional limit, a material's stress is directly proportional to its strain.

Modulus of toughness

The area under the entire stress-strain diagram, which represents the amount of energy absorbed by the material per unit volume up to rupture.

Modulus of resilience

The area under the stress-strain diagram up to the yield point, representing the maximum energy absorbed by the material per unit volume before it deforms permanently.

Young's modulus

The ratio of normal stress to normal strain, also known as the modulus of elasticity.

Modulus of rigidity

The ratio of shear stress to shear strain.

Proportional limit

The point in the stress-strain curve beyond which stress is no longer proportional to strain.

Elasticity

The ability of a material to return to its original state after the load that caused its deformation is removed.

Yielding

The beginning of plastic deformation where a material starts to break down after the elastic limit is reached.

Strain hardening

The region in the stress-strain curve where the strength of the material increases after yielding until the ultimate strength is reached.

Relaxation

Long term, time-dependent loss of prestress due to constant elongation of tendons.

Pre-tensioning

Method of prestressing where the tendons are stressed prior to pouring of concrete.

Post-tensioning

Method of prestressing where the tendons are stressed after concrete has hardened.

Modulus of rupture

Concrete tensile strength in flexure/bending.

Load factor

A factor that accounts for deviations of the actual load from the nominal load, for uncertainties in the analysis that transforms the load into a load effect, and for the probability that more than one extreme load will occur simultaneously.

Strength reduction factor

A factor that accounts for deviations of the actual strength from the nominal strength due to variations in material strengths and dimensions.

Creep

Time-dependent permanent deformation of concrete due to sustained loading.

Fatigue

A material's tendency to break after being subjected to repeated cycles of stress.

Allowable stress

The largest safe stress that can safely be carried by a material.

Factor of safety

The ratio of failure stress and working stress.

Isotropic material

A material that has identical physical and mechanical properties in all directions at a given point.

Orthotropic material

A material that has different physical and mechanical properties in all three perpendicular directions at a given point.

Homogeneous material

A material that has the same physical and mechanical properties on all points.

Focus

The place in the Earth's crust where an earthquake originates.

Epicenter

The point on the Earth's surface that is vertically above the focus.