Wk 8, 9, 10

Question 1

I (second moment of area) for vertical and lateral for this section

Answer 1

bd^3 / 12

calculate like for normal for I (xx)
E.G. b = 50, d=150

For I (yy) it’s reversed
E.G. b=150, d=50

Question 2

what is each scenario an example of?

Ktotal for each scenario?

Answer 2

Question 3

Damped natural frequency eqn

Answer 3

Question 4

Circular natural frequency eqn

Answer 4

Question 5

Initial loading eqn

Answer 5

Question 6

New amplitude eqn (been loaded)

Answer 6

Question 7

Interpret this eqn

Answer 7

Question 8

Eqn for the displacement of a SDOF (spring/mass model)

Answer 8

Question 9

WK8, Q2

Answer 9

Question 10

WK8, Q3

Answer 10

Question 11

WK9, Q1,2

Answer 11

Q2C)

1) increase frame stiffness, hence increase p, hence reduce w/p

INCREASE frame stiffness: increase x-sectional area of beams..,
use higher stiffness materials (higher E)

2) increase level of damping by use of viscous dampers, hence increase damping ratio

Question 12

Stiffness for rigidly connected column (both ends)

and not for both ends

Answer 12

Rigid
(12EI) / (L^3)

Not
3EI / L^3

Question 13

17-18, Q3a,b

Answer 13

b)
increase stiffness in column, increase EI, use columns with larger X-sectional areas

Add bracings between the columns to reduce lateral displacement.

Question 14

18-19, Q3a,b

Answer 14

Question 15

19-20, Q3a

Answer 15

Question 16

22-23, Q3a

Answer 16

Question 17

Unit for coefficient of damping?

Answer 17

Kg/s
symbol = C

Question 18

Unit for P (circular natural freq)

Answer 18

rads^-1