D1.D.1.3 AASHTO (ASD) Design Parameters

The following table outlines the parameters that can be used with the AASHTO (ASD) code along with the default values used if not explicitly specified.

Table 1. AASHTO (ASD) Design Parameters
Parameter Name	Default Value	Description
BEAM	1.0	0.0 = Design at ends and those locations specified by the SECTION command. 1.0 = Design at ends and every 1/12^th point along the member length.
CB	1.0	Cb value as used in the calculation of Fb 0.0 = Cb value to be calculated Any other value will be used in the calculations.
CMY CMZ	0.85 for sideswayand calculatedfor no sidesway	Cm value in local y & z axes
DFF	None.(Mandatory for a deflection check)	Deflection length / Maximum allowable local axis deflection.
DJ1	Start joint of member	Joint No. denoting starting point for calculating Deflection Length.
DJ2	End joint of member	Joint No. denoting ending point for calculating Deflection Length.
DMAX	1000.0	Maximum allowed section depth (in current length units) for a section to be selected with the SELECT command.
DMIN	0.0	Minimum allowed section depth (in current length units) for a section to be selected with the SELECT command.
FYLD	36 KSI	Yield strength of steel in current units.
KY	1.0	Effective length factor to calculate slenderness ratio for buckling about local y-axis. Usually this is the minor axis.
KZ	1.0	Effective length factor to calculate slenderness ratio for buckling about local z-axis. Usually this is the major axis.
LY	Member Length	Length to calculate slenderness ratio for buckling about local Y axis.
LZ	Member Length	Same as above except in local z-axis.
MAIN	0.0	0.0 =check for slenderness 1.0 =suppress slenderness check
NSF	1.0	Ratio of "Net cross section area" / ‘Gross section area’ for tension member design.
PROFILE	None	Used in member selection. Refer to TR.48.1 Parameter Specifications for details.
PUNCH		1.0 = K-Overlap 2.0 = K-Gap 3.0 = T and Y 4.0 = Cross with diaphragms 5.0 = Cross without diaphragms
RATIO	1.0	Permissible ratio of the actual to allowable stresses.
SSY	0.0	0.0 =Sidesway in local y-axis. 1.0 =No sidesway in local y-axis
SSZ	0.0	0.0 =Sidesway in local z-axis. 1.0 =No sidesway in local z-axis.
STIFF	Greater of member length or depth of beam.	Spacing of stiffeners for plate girder design in current length units.
TRACK	0	Level of detail in Output File: 0 = Print the design output at the minimum detail level. 1 = Print the design output at the intermediate detail level. 2 = Print the design output at maximum detail level.
UNF	1.0	Unsupported length provided as a fraction of actual member length used for lateral-torsional buckling calculation. Note: If both `UNF` and `UNL` parameters are specified, the effective length used is `UNF`×`UNL`.
UNL	Member Length	Unsupported length for calculating allowable bending stress. Used for the lateral-torsional buckling calculation. Value should be in the current units of length.
WSTR	0.4 x FYLD	Allowable welding stress