BUILDING IRREGULARITY

Question 1

is one in which the lateral stiffness is less than 70 percent of that in the story above or less than 80 % of the average stiffness of the three stories above

Answer 1

STIFFNESS IRREGULARITY -SOFT STORY

Question 2

shall be considered to exist where the effective mass of any story is more than 150% of the effective mass of an adjacent story.

Answer 2

WEIGHT(MASS) IRREGULARITY

Question 3

shall be considered to exist where the horizontal dimension of the lateral-force-resisting system in any story is more than 130% of that in any adjacent story.

Answer 3

VERTICAL GEOMETRY IRREGULARITY

Question 4

greater than the length of those elements

Answer 4

IN-PLANE DISCONTINUITY IN VERTICAL LATERAL-FORCE-RESISTING ELEMENT IRREGULARITY

Question 5

is one in which the story strength is less than 80% of that in the story above.

Answer 5

DISCONTINUITY IN CAPACITY - WEAK STORY IRREGULARITY

Question 6

shall be considered to exist when the maximum story drift, computed including accidental torsion, at one end of the structure transverse to an axis is more than 1.2 times the average of the story drifts of the two ends of the structure.

Answer 6

TORSIONAL IRREGULARITY - TO BE CONSIDERED WHEN DIAPHRAGMS ARE NOT FLEXIBLE

Question 7

Plan configurations of a structure and its lateral-force-resisting system contain re-entrant corners, where both projections of the structure beyond re-entrant corner greater than 15% of the plan dimension of the structure in the given direction.

Answer 7

RE-ENTRANT CORNER IRREGULARITY

Question 8

Diaphragms with abrupt continuities or variations in stiffness, including those having cutout or open areas greater than 50 percent of the gross enclosed area of the diaphragm, or changes in effective diaphragm stiffness of more than 50 percent from one story to the next

Answer 8

DIAPHRAGMS DISCONTINUITY IRREGULARITY

Question 9

Discontinuities in a lateral force path, such as out-of-plane offsets of the vertical elements.

Answer 9

OUT-OF-PLANE OFFSETS IRREGULARITY

Question 10

The vertical lateral-load-resisting elements are not parallel to or symmetric about the major orthogonal axes of the lateral force-resisting systems.

Answer 10

NONPARALLEL SYSTEMS IRREGULARITY

Question 11

Is the total strength of all seismic-resisting elements sharing the story for the direction under consideration.

Answer 11

STORY STRENGTH