April 6, 2011
|
Seismic,
RISA-3D,
Loads,
RISAFloor,
New
V-Brace
frames
in
RISA-3D
seismic
design
have
unbalanced
forces
shown
on
both
the
beams
and
braces.
As
brace
frames
displace
under
lateral
loads,
one
brace
will
buckle
and
its
force
decreases
while
the
other
brace
in
tension
will
have
an
increase
of
force
until
it
reaches
yield.
The
beam
and
connections
must
have
enough
strength
to
resist
this
unbalanced
vertical
force.
The
brace
forces
are
shown
in
the
beam
and
brace
detail
report
as
well
as
the
resultant
unbalanced
force
per
AISC
341-10
Section
13.4.
RISA-3D
does
not
automatically
apply
these
forces
to
the
beams.
To
account
for
the
unbalanced
vertical
force
in
your
model,
you
can
apply
these
vertical
point
loads
in
RISAFloor
without
the
braces
present…