October 19, 2018
|
RISA-3D,
RISAFloor,
New,
Steel,
Eurocode
Eurocode
lateral
torsional
buckling
capacity
is
calculated
per
equations
in
Annex
F
in
the
ENV
1993-1-1:1992.
This
calculation
uses
variables
C1,
C2
and
C3.
Since
there
is
no
generic
formula
in
the
Eurocode
to
calculate
the
moment
gradient
factor,
C1,
RISA
will
use
the
widely
accepted
López,
Yong
and
Serna
method
by
default.
The
method
proposed
by
López,
Yong
and
Serna
in
their
paper
“
Lateral-Torsional
Buckling
of
Steel
Beams:
A
General
Expression
for
the
Moment
Gradient
Factor”
to
determine
the
moment
gradient
factor
takes
into
account
both
the
moment
diagram
and
support
conditions.
The
general
proposed
closed
form
expression
presented
by
López
et
al
is
the
following:
Where
k
is,
A1
and
A2
are
given
by,
where,
The
contribution
of
the
support
conditions
are
considered
in
the
k1
and
k2
terms.
When
lateral
bending
and
warping
are
free,
k1
or
k2
is
equal
to
1.0
for
the
corresponding
support.
When
lateral
bending
and
warping
are
prevented,
k1
or
k2
is
taken
as
0.5.
The
values
rendered
using
this
closed
form
expression
have
been
shown
to
match
closely
with
numerical
results
in
comparison
to
methods
proposed
by
AISC
and
BS
5950-1.
However,
the
user
can
always
override
this
value
within…
