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D1.K.2.3 Design Parameters

The program contains a large number of parameter names which are required to perform design and code checks.  These parameter names, with their default values, are listed in the following table.

The default parameter values have been selected such that they are frequently used numbers for conventional design.  Depending on the particular design requirements for an analysis, some or all of these parameter values may have to be changed to exactly model the physical structure

Table 1. Design Parameters for ANSI/AISC N690-1984
Parameter Name Default Value Description
CODE -

Must be specified as AISC N690 1984 to use the ANSI/AISC N690-1984 code for checking purposes.

Design code to follow. See TR.48.1 Parameter Specifications.

CAN 0

Used for Deflection Check only.

  • 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
CB 1.0

Bending coefficient dependent upon moment gradient

0.0 = CB is calculated itself

Any other user-defined value is accepted.

CMY

CMZ

0.85 for sidesway and calculated for no sidesway Cm value in local y & z axes
CT 0.75 Reduction Coefficient in computing net effective net area of an axially loaded tension member.
DFF None(Mandatory for deflection check) "Deflection Length" / Maximum allowable local deflection
DJ1 Start Jointof member Joint No. denoting starting point for calculation of "Deflection Length"
DJ2 End Joint of member Joint No. denoting end point for calculation of "Deflection Length"
DMAX 45 inch Maximum allowable depth
DMIN 0.0 inch Minimum allowable depth
FU 60 KSI Ultimate tensile strength of steel in current units.
FYLD 36 KSI Yield strength of steel in current units.
KY 1.0 Effective Length Factor for Compression in local y-axis. Usually, this is minor axis.
KZ 1.0 Effective Length Factor for Compression in local z-axis. Usually, this is major axis.
LY Member Length Length to calculate slenderness ratio for buckling about local Y axis.
LZ Member Length Same as above except in z-axis (major).
MAIN 0.0

Design for slenderness.

  • 0. Check for slenderness
  • 1. Suppress slenderness check
NSF 1.0 Net section Factor for tension members
PROFILE None

Used to search for the lightest section for the profile(s) specified for member selection. See TR.48.1 Parameter Specifications for details.

RATIO 1.0 Permissible ratio of the actual to allowable stresses.
SFC 1.0 Stress limit coefficient for compression (SLC) as found in Table Q 1.5.7.1.
SFT 1.0 Stress limit coefficient for tension (SLC) as found in Table Q 1.5.7.1.
SMY 1.0 Stress limit coefficient for minor axis bending (SLC) as found in Table Q 1.5.7.1.
SMZ 1.0 Stress limit coefficient for major axis bending (SLC) as found in Table Q 1.5.7.1.
STIFF Member length or depth whichever is greater Spacing of stiffeners for plate girder design
STYPE 0.0

Steel type:

  • 0.0 = Normal Steel
  • 1.0 = Austenitic Stainless Steel
TMAIN

240 for main member

300 for "Truss" member

 Slenderness limit under tension
TRACK 0.0

Controls the levels of detail to which results are reported.

  • 0 = Minimum detail
  • 1 = Intermediate detail level
  • 2 = Maximum detail
UNB Member Length Unsupported length of the bottom* flange for calculating allowable bending compressive stress. Will be used only if flexural compression on the bottom flange.
UNT Member Length Unsupported length of the top* flange for calculating allowable bending compressive stress. Will be used only if flexural compression on the top flange.

D1.K.2.3.1 Notes

  1. All values are entered in the current units
  2. parameters DMAX and DMIN are only used with the MEMBER SELECTION command
Parent topic: D1.K.2. ANSI/AISC N690-1984 Code