Civil Engineering Reference
In-Depth Information
S
TRUCTURAL
I
RREGULARITIES
P
LAN
I
RREGULARITIES
E
LEVATION
I
RREGULARITIES
Re-Entrant Corner /
In-Plan Offsets
Non-Parallel Lateral
Resisting Systems
Re-Entrant Corner /
Vertical Offsets
Non-Parallel Lateral
Resisting Systems
Lateral System
Discontinuities (Horizontal)
Diaphragm
Discontinuities
Lateral System
Discontinuities (Horizontal)
Weak and/or Soft
Storeys
Figure A.2
Typical structural irregularities
B
D
I
RREGULAR
B
b
b
b
b
2
1
b
B
B
Figure A.3
Common regular and irregular shapes for plan layout
to quantify torsional effects. Criteria for regular structures are outlined hereafter for plan and elevation,
respectively.
A.1.1 Plan Regularity
Structures with regular plan confi gurations are compact, i.e. described by polygonal convex lines.
Square, rectangular and circular shapes are compact. Square or rectangular confi gurations with minor
re-entrant corners can still be considered regular. Large re-entrant corners creating crucifi x forms give
rise to irregular confi gurations (Figure A.3). The dynamic response of the wings (also termed ' multi -
mass structures ') generally differs from that of the structure as a whole. Multi-mass structures are highly
vulnerable at connections between wings. Relative displacements cause severe damage at the intersec-
tion of various blocks; torsional effects are likely to occur. Other plan confi gurations with geometrical
