Formulas

Question 1

What is the formula for (axial) Stress?

Answer 1

F = P/A 
F = Stress ( # / sq in, k / sq in) PSI,  KSI
P = Axial Load ( # , k )
A = Cross sectional area  ( sq in, sq ft )

Question 2

What is the formula for Unit Strain?

Answer 2

Delta L / L

Question 3

What is the modulus of elasticity?

Answer 3

E, think stress over strain strain diagram

P/A ) / (Delta L /L

Question 4

What is another name for the modulus of Elasticity?

Answer 4

Young’s Modulus

Hooke’s Law

Question 5

What formula is used to calculate elongation and shortening?

Answer 5

Delta L = ( P L) / ( A E)
Units must be in INCHES
L= Original Length
E = Modulus of Elasticity
P = Load
A = Area

Question 6

When calculating deformation in a beam, if the area of the beam doubles, what happens to the overall deformation?

Answer 6

Halves, remember*

Delta L = ( P L) / ( A E)

Question 7

When calculating deformation in a beam, if the load on the beam doubles, what happens to the overall deformation?

Answer 7

Doubles, remember*

Delta L = ( P L) / ( A E)

Question 8

What is the formula for thermal expansion of a beam

Answer 8

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

Question 9

What is the coefficient of thermal expansion?

Answer 9

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

Question 10

What is the primary factor in the equation for shear, and what are the units that correspond to shear

Answer 10

Area, measured in inches squared. Section modulus dictates a materials bending moment (flexure)

Question 11

What is the formula for section modulus, and what is the unit it is measured in?

Answer 11

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

Question 12

What is the formula F=P/A measuring

Answer 12

Axial stress = Load / Area

Question 13

What is the formula delta = PL /AE measuring?

Answer 13

deformation = (Load x Length) / Area x Modulus of Elasticity

Question 14

What is the Modulus of Elasticity for Steel?

Answer 14

29,000 ksi

Question 15

What is the moment of inertia?

Answer 15

It is an objects tendency to rotate about its axis

Question 16

What is the formula for the moment of inertia of a rectangle

Answer 16

I = bd^3 / 12

Question 17

What formula is deflection or stiffness of a member related to?

Answer 17

The moment of inertia

Question 18

What is the equation to measure wind pressure?

Answer 18

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

Question 19

What is the formula for lateral base shear?

Answer 19

V = CS x W
V = Base Shear
CS = Spectral Response Acceleration

Question 20

What does CS or the Seismic Design Category take into account?

Answer 20

Geographic Location, Seismic Risk, Seismic History

Importance Factor

Period, Period of the building, Period of the ground