Construction and Materials Flashcards
stress
force per unit area acting on a material
tensile stress
material stretches when exposed to stress
compressive stress
material shortens when exposed to stress
shearing stress
stress is enough to cut through the material
strain
“stretch” - measurable load which allows a material to be displaced from its dimension
proportional limit
the point in a materials stress strain relationship where the increase in force and stretch is related linearly. after the force is released, the strain is relieved and the material returns to its original form
elastic limit
maximum stress limit within the linear relationship of the proportional limit
yield point
point on the stress-strain relationship where the stretch increases without an increase in the force. the material is now permanently deformed
ultimate strength
maximum force that will cause complete failure or the breaking strength
modulus of elasticity
“youngs modulus” - the ratio of the applied force to stretch exhibited within the proportional limit. expressed in in tension or compression.
poisson’s ratio
the ratio of the amount of lateral stretch of a material to the longitudinal stretch when an axial force is applied within the proportional limit. most common metals will be between 0.0 and 0.5. eq - rubber band stretches longitudinally with force and becomes thinner. when force is released, it returns to its shape
ductility
the ability of a material to deform before it fractures when a load is applied. could be states as pliable, supple, springy, soft. common metals - aluminum, tin, copper, mild steel, lead.
toughness
materials ability to absorb impact or shock load in the plastic range without deforming or fracturing. the ability to bend and the resistance to fracture with stress. can be found through strength and ductility
brittle
materials that break when applied to a force without absorbing energy. eq - ceramics and glass
bending moment
the sum of moments about the section of all external forces acting to one side of that section
Safe working load
breaking strength / factor of safety
OP
outside perimeter = (2) (length + width + recess)
IP
Inner perimeter = OP + [(4) (2 x (- thickness))]
MP
Mean perimeter = OP - [(4) (2 x (thickness/2))]
nominal dimensions
“trade dimensions” specified dimensions + any surrounding material ie brick + mortar
specified dimensions
actual manufactured dimensions of the material with no additional considerations
bond pattern
typical brick laying pattern. 1/2 bond is where approx 1/2 brick length overlaps with the brick below
Hip Roof is the same area as….
a gable roof
pitch
rise/run
Square Foot of Contact Area
dimensions of the face of the concrete that will come in contact with the formwork
zero place
a counting error often not considered when estimating amounts of materials. to have an evenly spaced fence, you need a starting pole at the zero place.
closed traverse
land survey technique where the survey shots start and end on point with a known location
Open traverse
land survey technique where the first point is known, but not the second.
Cannot check for error using this method, so need to verify with additional measurments
vertical control
establishes elevations which are preserved for the duration of the project
horizontal control
establishes coordinates for the duration of the survey
theodolite
survey equipment to measure both horizontal and vertical areas.
total station
electronic survey equipment
Benchmark (BM)
relatively permanent point of known elevation (datum)
Back sight (BS)
sight taken to the level rod held at a point of known elevation (either BM or TP/ turning point)
Height of instrument (HI)
elevation of line of sight of the telescope
foresight (FS)
a sight taken on any point to determine its elevation
