D1.C.6 Design Parameters
Design per LRFD specifications is requested by using the CODE parameter. Other applicable parameters are summarized in Table 24. These parameters communicate design decisions from the engineer to the program and thus allow the engineer to control the design process to suit an application's specific needs.
The default parameter values have been selected such that they are frequently used numbers for conventional design. Depending on the particular design requirements, some or all of these parameter values may be changed to exactly model the physical structure.
The parameters DMAX and DMIN are applicable for member selection only.
Parameter Name  Default Value  Description 

CODE   
Must be specified LRFD or LRFD3 for 3rd Edition. Must be specified LRFD2 for 2nd Edition. 
AXIS  1 
1 = Design single angles for bending about their principle axis. 2 = Design single angles for bending about their geometric axis. 
BEAM  1.0 

CAN  0 
0 = deflection check based on the principle that maximum deflection occurs within the span between DJ1 and DJ2. 1 = deflection check based on the principle that maximum deflection is of the cantilever type (see D1.B.1.2 Design Parameters) 
CB**  1.0  Coefficient Cb per Chapter F of AISC LRFD. If Cb is set to 0.0, it will be calculated by the program. Any of value will be used directly in design. 
DFF  None (Mandatory for deflection check)  "Deflection Length" / Maximum allowable local deflection 
DJ1  Start Joint of Member  Joint No. denoting starting point for calculation of "Deflection Length" (see D1.B.1.2 Design Parameters) 
DJ2  End Joint of Member  Joint No. denoting end point for calculation of "Deflection Length" (see D1.B.1.2 Design Parameters) 
DMAX  45.0 in.  Maximum allowable section depth. 
DMIN  0.0 in.  Minimum allowable section depth 
FLX  1 
1 = Single angle member is not fully braced against lateral torsional buckling. 2 = Single angle member is fully braced against lateral torsional buckling. 3 = Single angle member is braced against lateral torsional buckling at the point of maximum moment. 
FYLD  36.0 ksi  Yield strength of steel. 
FU  60.0 ksi  Ultimate tensile strength of steel. 
KX  1.0  K value for flexuraltorsional buckling. 
KY  1.0 
Effective length factor to calculate slenderness ratio for buckling about local yaxis. Usually this is the minor axis. 
KZ  1.0 
Effective length factor to calculate slenderness ratio for buckling about local zaxis. Usually this is the major axis. 
LX  Member Length  Length used for flexuraltorsional buckling. 
LY  Member Length  Length to calculate the slenderness ratio for buckling about the local yaxis. 
LZ  Member Length  Length to calculate the slenderness ratio for buckling about the local zaxis. 
MAIN  0.0 
0.0 = check for slenderness 1.0 = suppress slenderness check Any value greater than 1 = Allowable KL/r in compression. 
NSF  1.0  Net section factor for tension members. 
PROFILE  Used in member selection. Refer to TR.48.1 Parameter Specifications for details.  
RATIO  1.0  Permissible ratio of actual load effect to design strength. 
STIFF  Member Length or depth, whichever is greater  Spacing of stiffeners for beams for shear design. 
STP  1 
Section type to determine F_{r} (compressive residual stress in flange) per 3rd Ed. LRFD spec., p 16.197.

TMAIN  300  Any value greater than 1 = Allowable KL/r in tension. 
TRACK  0.0 
Specified the level of detail included in the output.

UNB  Member Length  Unsupported length (L_{h}) of the bottom* flange for calculating flexural strength. Will be used only if flexural compression is on the bottom flange. 
UNT  Member Length  Unsupported length (L_{h}) of the top* flange for calculating flexural strength. Will be used only if flexural compression is on the top flange. 
*Top and Bottom represent the positive and negative side of the local Y axis (local Z axis if SET Z UP is used).
The STIFF parameter represents the term a as defined in Section F2, page 6113 of the LRFD 2nd edition manual.
** Nondefault values of CB must be reentered before every subsequent CHECK CODE or SELECT command.