...
In
...
addition
...
to
...
gravity
...
load,
...
should
...
initial
...
P-Delta
...
analysis
...
contain
...
notional
...
load?
...
Answer:
...
To
...
fully
...
account
...
for
...
P-Δ
...
and
...
P-δ,
...
each
...
design
...
...
...
must
...
be
...
run
...
as
...
a
...
nonlinear
...
P-Delta
...
analysis
...
which
...
includes
...
notional
...
load.
...
To
...
fully
...
account
...
for
...
P-Δ
...
in
...
buildings
...
with
...
either
...
rigid
...
or
...
semi-rigid
...
diaphragms,
...
an
...
initial
...
P-Delta
...
analysis
...
should
...
be
...
performed
...
with
...
gravity
...
load,
...
then
...
additional
...
loads
...
should
...
be
...
applied
...
linearly.
...
Justification
...
is
...
that
...
total
...
axial
...
load
...
(P)
...
at
...
each
...
story
...
level
...
remains
...
constant
...
regardless
...
of
...
lateral
...
and
...
notional
...
load.
...
For
...
subsequent
...
linear,
...
...
,
...
and
...
...
...
analyses,
...
...
automatically
...
implements
...
this
...
procedure
...
when
...
running
...
constant
...
P
...
-
...
Δ
...
analysis
...
.
...