August 18, 2011
|
RISA-3D,
Loads,
RISAFloor,
RISA-2D,
New
RISA-3D,
RISA-2D
and
RISAFloor
have
the
capability
to
project
distributed
and
area
loads
onto
members.
Consider
the
case
of
snow
load
on
two
buildings:
one
with
a
flat
roof
and
one
with
a
sloped
roof.
Ignoring
the
concept
of
shedding,
if
both
buildings
have
the
same
footprint
then
they
should
both
have
the
same
total
weight
of
snow
applied
to
them.
This
is
because
the
snow
doesn’t
care
what
the
shape
of
a
building
is
as
it
falls.
The
same
total
amount
of
snow
will
fall
on
a
given
acre
regardless
of
what’s
on
it.
Below
is
an
image
illustrating
roof
rafters
from
both
the
sloped
and
flat
roof
beams.
In
both
cases
a
vertical
snow
load
of
100
lbs/ft
has
been
applied
in
the
global
Y
direction.
Note
that
the
total
end
reaction
on
the
sloped
rafter
is
1.41k
versus
only
1.00k
for
the
flat
rafter.
This
is
because
the
sloped
rafter
is
actually
14.1
ft
long,
and
we
have
applied
the
load
as
100
lbs
per
linear
foot
of
rafter.
In
order
to
get
the
correct
behavior
for
snow
we
need
to
project
the
load
onto
the
horizontal
plane.
The
image
below
shows
the
same
members,
but
with…
