Structural Systems/Codes

Question 1

Moment Resisting Frames

Answer 1

Resist forces in members and joints primarily by flexure and rely on a frame to carry both vertical and lateral loads.

Question 2

Special Moment Resisting Frames

Answer 2

Specially detailed to ensure ductile behavior and comply with respective codes (ACI 318, AISC 341)

Question 3

Bearing Wall Systems

Answer 3

Aka Box Systems

Relies on shear and load-bearing walls to carry vertical and lateral loads (dead, live and seismic loads)

Does not have a complete vertical load-carrying space frame.

(Sec 6.21)

Question 4

Which has smaller natural frequency? Steel or Concrete MF?

equal heights, equal moments of inertia

Answer 4

Steel frame
Longer period
More ductile
Lower frequency

Question 5

Which has larger damping ratio?

Steel or concrete MRF?

Answer 5

Concrete Moment Frame

Sec 4.10

Question 6

Are plastic hinges designed in columns girders or both?

Answer 6

In girders only!

Girders with hinges = distortion/sagging/misalignment without collapse.

Columns with hinges = collapse mechanism.

Question 7

Response modification factor (or ductility factor) for an intermediate reinforced masonry shear wall (bearing).

Answer 7

R = 3.5

Question 8

How is base shear calculated in the IBC?

Answer 8

Weight of structure multiplied by seismic response coefficient.

V=Cs*W

Question 9

What is the seismic response coefficient based on? (Cs)

Answer 9

Expected ground acceleration (Sd1, Sds)
Building occupancy (risk category, importance factor)
Building weird (T)
Soil profile type (site class, Fa, Fv)
Structural system (R, ductility factor)

Cs = Sds / (R/Ie)

Question 10

R of a special steel concentrically braced frame that is not considered a bearing wall system?

Answer 10

R= 6

Question 11

R of an ordinary reinforced concrete shear wall that is not considered a bearing wall system?

Answer 11

R=5

Question 12

Which has a smaller R value, a steel or concrete special moment resisting frame?

Answer 12

They are both 8!!

Question 13

R value for a football grandstand with bleachers

Answer 13

Other category: R=1.25

Question 14

R value of a tall vertical tank supported on a raised platform supported by a tower similar to a steel concentrically braced structure framework

Answer 14

R=6

Tanks/vessels on structural towers similar to buildings

Table 15.4-1

Special concentric brace frame

Question 15

Limitation on drift when it is not tolerable

Answer 15

Percentage of height based on structural system

Question 16

Which MF’s are permitted in seismic design category F?

Answer 16

Only SMF.

IMF and OMF not permitted in SDC F

Question 17

What % of warehouse LL should be added to the dead load when calculating base shear (effective seismic weight)

Answer 17

25% of warehouse LL

ASCE 710
12.7.2

Question 18

Range of mapped MCE ground motion for Arizona with 0.2s spectral response acceleration

Answer 18

50% of g max

7.9% of g min

Question 19

Is S1 every greater than Ss?

Answer 19

No, S1 < Ss always