To define the member parameters used in an AISC 360
direct analysis, use the following procedure.
Note: The yield strength of the steel is taken from the
material definition. If
the material definition is not provided for a member, then a default value of
Fy = 36 ksi is used.
-
On the
Loading ribbon tab, select the
Direct Analysis tool in the
Define Load Systems group.
The
Create New Load Items dialog open.
-
Specify the initial τb value:
Members whose flexural stiffness are considered to
contribute to the lateral stiffness of the structure will have their flexural
stiffness (EI) reduced by
0.8×τb
.
-
Select the
FLEX Parameter tab.
-
Type a
FLEX value.
-
Click
Add.
- Optional:
Identify any axial members which contribute to the lateral
stiffness of the structure:
-
Select the
AXIAL Parameter tab.
-
Click
Add.
-
Click
Close.
-
In the
Load & Definition dialog,
expand the
group.
-
Assign each of the
FLEX
and
AXIAL
parameters listed to the corresponding members
in the model.
You must add one or more load cases with notional loads to your model for
a direct analysis.