September 11, 2017
|
Seismic,
RISA-3D,
New,
Analysis,
Wind
RISA-3D
v15
now
includes
automatic
drift
definitions
for
diaphragms
as
well
as
simplified
story
drift
application.
The
reported
drift
results
have
been
updated
as
well,
and
are
now
much
more
relevant
for
today’s
codes.
Drift
results
will
report
results
in
red
text
when
seismic
drift
exceeds
the
limits
specified
in
ASCE-7
2010.
In
addition,
deflection
amplification
due
to
2nd
order
effects
is
now
reported,
and
will
appear
in
red
text
whenever
it
exceeds
the
AISC
14th
edition
requirements.
Drift
Definitions
Spreadsheet
The
new
Drift
Definitions
spreadsheet
defines
where
the
drift
calculations
will
be
performed.
If
the
model
contains
diaphragms,
the
joints
connected
to
that
diaphragm
will
automatically
be
considered
in
drift
calculations.
In
addition,
Drift
calculations
may
be
performed
at
specific
elevations
(where
diaphragms
don’t
exist)
merely
by
specifying
these
elevations
in
the
spreadsheet.
The
user
may
also
specify
individual
joints
to
be
used
in
drift
calculation.
This
can
be
helpful
for
points
that
don’t
line
up
well
from
floor
to
floor
or
don’t
behave
the
same
as
other
joints
at
that
elevation.
For
example:
Inclined
columns
Columns
that
span
multiple
stories
Center
of
Mass
locations
What
is
Story
Drift
and
Drift
Ratio?
The
Drift
at
a
given
level
is…