STRUCTURAL TERMS (OLD VERSION) Flashcards
identification
_____ are caused by the direct contact of one body with the surface of another
surface forces
a _____ is developed when one body exerts a force on another body without direct physical contact between the bodies
body force
all cross sections are the same throughout its length
prismatic
has the same physical and mechanical properties throughout its volume
homogeneous material
has these same properties in all directions
isotropic material
reflect the probability that the total loading R will occur for all the events stated
load factors
are determined from the probability of material failure as it relates to the material’s quality and the consistency of its strength
resistance factors (𝜙)
if we select two line segments that are originally perpendicular to one another, then the change in angle that occurs between them is referred to as ____
shear strain
a slight increase in stress above the elastic limit will result in a breakdown of the material and cause it to deform permanently
yielding
the stress that causes yielding is called the _____, 𝜎𝑌, and the deformation that occurs is called _____
yield stress or yield point; plastic deformation
when yielding has ended, an increase in load can be supported by the specimen, resulting in a curve that rises continuously but becomes flatter until it reaches a maximum stress referred to as the ultimate stress
strain hardening
up to the ultimate stress, as the specimen elongates, its cross-sectional area will decrease
necking
any material that can be subjected to large strains before it fractures
ductile materials
materials that exhibit little or no yielding before failure
brittle materials
as a material is deformed by an external load, the load will do external work, which in turn will be stored in the material as internal energy; this energy is related to the strains in the material, and so it is referred to as _____
strain energy
when the stress reaches the proportional limit, the strain-energy density is referred to as the _____
modulus of resilience
this quantity represents the entire area under the stress-strain diagram, and therefore it indicates the maximum amount of strain-energy the material can absorb just before it fractures
modulus of toughness
the ratio of modulus of toughness to the modulus of resilience
ductility factor
when a material has to support a load for a very long period of time, it may continue to deform until a sudden fracture occurs or its usefulness is impaired
creep
when a metal is subjected to repeated cycles of stress or strain, it causes its structure to break down, ultimately leading to fracture
fatigue
a condition where a material break down and deforms permanently even due to a slight increase in stress above the elastic limit
plasticity
when the plastic moment is removed from the beam then it will cause _____ to be developed in the beam
residual stress
members that are slender and support loadings that are applied perpendicular to their longitudinal axis
beam
the change in volume per unit volume is called the “volumetric strain” or the _____
dilatation
it occurs when a building period coincides with the earthquake period
resonance
occurs when the structures center of mass does not coincide with the center of rigidity
torsional shear stress
measured by a seismometer
ground displacement
reciprocal of deflection
rigidity of structure
it is the space between two adjacent floors
story
rigid horizontal planes used to transfer lateral forces to vertical resisting elements
diaphragms
wall designed to resist lateral forces acting on its own plane, typically wind and seismic loads
shear wall
it is the point where the object “suffers” no torque by the effect of the gravitational force acted upon it
center of gravity
it is point through which the resultant of the resistance to the applied lateral force acts
center of rigidity
it is point through which the applied seismic force acts
center of mass
it is the distance between the center of rigidity and center of mass
eccentricity
it is the total design lateral force
design seismic base shear
inverse of stiffness
flexibility of a structure
it is the displacement of one level relative to the level above or below
story drift
lateral displacement of the story relative to the base
story displacement
rate at which natural vibration is absorbed
damping
instrument use to measure the peak ground acceleration, which is one of the most important characteristics of an earthquake
seismometer
instrument use to measure the strain of rock under pressure
magnetometer
the originating earthquake source of the elastic waves inside the earth which cause shaking of ground due to earthquake
focus (hypocenter)
the point on the earth’s surface directly above the focus
epicenter
story drift divided by the story height
story drift ratio
a measure of the strength of shaking during earthquake
intensity
a measure of energy released in an earthquake
magnitude
is a state in saturated cohesionless soil wherein the effective shear strength is reduced to negligible value
liquefaction