Formulas Flashcards
What is the formula for (axial) Stress?
F = P/A F = Stress ( # / sq in, k / sq in) PSI, KSI P = Axial Load ( # , k ) A = Cross sectional area ( sq in, sq ft )
What is the formula for Unit Strain?
Delta L / L
What is the modulus of elasticity?
E, think stress over strain strain diagram
P/A ) / (Delta L /L
What is another name for the modulus of Elasticity?
Young’s Modulus
Hooke’s Law
What formula is used to calculate elongation and shortening?
Delta L = ( P L) / ( A E) Units must be in INCHES L= Original Length E = Modulus of Elasticity P = Load A = Area
When calculating deformation in a beam, if the area of the beam doubles, what happens to the overall deformation?
Halves, remember*
Delta L = ( P L) / ( A E)
When calculating deformation in a beam, if the load on the beam doubles, what happens to the overall deformation?
Doubles, remember*
Delta L = ( P L) / ( A E)
What is the formula for thermal expansion of a beam
Delta L = alpha (delta T) L Delta L = Final Length Alpha = Coefficient of thermal expansion Delta T = the overall temperature difference L = The original length
What is the coefficient of thermal expansion?
It is the coefficient signified by the symbol alpha and represented per degree (or every 100 degrees)
Steel = 0.0000065 in
Concrete = 0.0000060 in
Aluminum = 0.0000128 in
What is the primary factor in the equation for shear, and what are the units that correspond to shear
Area, measured in inches squared. Section modulus dictates a materials bending moment (flexure)
What is the formula for section modulus, and what is the unit it is measured in?
s=(b d^2) / 6
or
s = I / C where I is the moment of inertia and C is the distance to the objects neutral axis.
inches^3
What is the formula F=P/A measuring
Axial stress = Load / Area
What is the formula delta = PL /AE measuring?
deformation = (Load x Length) / Area x Modulus of Elasticity
What is the Modulus of Elasticity for Steel?
29,000 ksi
What is the moment of inertia?
It is an objects tendency to rotate about its axis
What is the formula for the moment of inertia of a rectangle
I = bd^3 / 12
What formula is deflection or stiffness of a member related to?
The moment of inertia
What is the equation to measure wind pressure?
q = 0.00256 x V^2 x Kz x Kzt x Kd x Iw V = Velocity Kz = 10 meters Standard measurement height Kzt = Terrain Kd = 0.85 Directional Factor Iw = Importance factor
What is the formula for lateral base shear?
V = CS x W V = Base Shear CS = Spectral Response Acceleration
What does CS or the Seismic Design Category take into account?
Geographic Location, Seismic Risk, Seismic History
Importance Factor
Period, Period of the building, Period of the ground
