February 28, 2011
|
Seismic,
RISA-3D,
Loads,
New
Applying
seismic
loads
to
structures
with
rigid
diaphragms
can
be
done
automatically
in
RISA-3D.
In
the
image
below
we
have
a
structure
that
has
rigid
diaphragms
and
the
seismic
load
has
already
been
applied
at
each
diaphragm
level.
To
do
this,
go
to
Advanced
>
Seismic
Loads
and
input
the
code
and
the
necessary
parameters
to
calculate
the
seismic
force
in
the
structure.
Note
that
we
also
need
the
Seismic
Weight
defined
in
a
load
combination
that
we
choose
here.
Once
we
hit
the
Calc
Loads
button
the
program
calculates
the
forces
at
each
diaphragm
level
in
each
orthogonal
direction
and
gives
the
parameters
used
to
calculate
these
forces.
For
the
ASCE
7-05
code
the
program
uses
the
Equivalent
Lateral
Force
Procedure.
If
we
then
hit
Generate,
these
loads
are
added
to
your
Basic
Load
Cases
automatically.
RISA-3D
also
automatically
provides
accidental
eccentricity
Basic
Load
Cases
prescribed
for
rigid
diaphragms…
