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D4.E.7 Design Parameters

The design parameters outlined in the following table may be used to control the design procedure. 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.

Note: Once a parameter is specified, its value stays at that specified number until it is specified again. This is the way STAAD.Pro works for all codes.
Table 1. Canadian Steel Design CSA-S16-09/14 Parameters
Parameter Name Default Value Description
CODE  

Must be specified as CANADIAN for S16-14.

Must be specified as CANADIAN 2009 for S16-09.

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

BEAM 1.0

Used to specify locations along member length considered for design:

  • 0.0  =  design only for end moments and those at locations specified by a SECTION command.
  • 1.0  =  Perform design for moments  at twelfth points along the beam.
CB 0.0 Value of ω2 (code Cl 13.6) to be used for calculations. ω2 is calculated internally if CB is 0.0 or not provided.
CMY ω1 calculated as per clause number 13.8.5 (a) ω1 in local Y direction for the member. The program calculated value of ω1 depends on whether the member is subjected to any transverse load or not:
  • ω1 = 0.6 - 0.4κ ≥ 0.4 if the member is not subjected to transverse loads between supports. Refer Clause 13.8.5 (a)
  • ω1 = 1.0 if the member is subjected to distributed loads or a series of point loads between supports. Refer Clause 13.8.5 (b)
  • ω1 = 0.85 if the member is subjected to a concentrated load or moment between supports. Refer Clause 13.8.5 (c)

STAAD.Pro will calculate ω1 based on the formula specified in 13.8.5 (a) unless you directly specify a value. You may specify any value between 0.4 to 1 for ω1 .

CMZ ω1 calculated as per clause number 13.8.5 (a) ω1 in local Z direction for the member. The program calculated value of ω1 depends on whether the member is subjected to any transverse load or not:
  • ω1 = 0.6 - 0.4κ ≥ 0.4 if the member is not subjected to transverse loads between supports. Refer Clause 13.8.5 (a)
  • ω1 = 1.0 if the member is subjected to distributed loads or a series of point loads between supports. Refer Clause 13.8.5 (b)
  • ω1 = 0.85 if the member is subjected to a concentrated load or moment between supports. Refer Clause 13.8.5 (c)

STAAD.Pro will calculate ω1 based on the formula specified in 13.8.5 (a) unless you directly specify a value. You may specify any value between 0.4 to 1 for ω1 .

CPSACING 0.0 Spacing between connectors of built-up members required for slenderness ratio calculation per Cl. 19.1.4.
DFF None(Mandatory for  deflection check) "Deflection Length"/Maxmimum Allowable local deflection.

See TR.40 Load Envelope for deflection checks using serviceability load envelopes.
DJ1 Start Joint of member Joint No. denoting start point for calculation of "Deflection Length"
DJ2 End Joint of member Joint No. denoting end point for calculation of "Deflection Length"
DMAX 45.0 in. Maximum allowable depth (Applicable for member selection)
DMIN 0.0 in. Minimum required depth (Applicable for member selection)
FLX 0

Parameter for specifying the flexural-torsional restraint condition.

  • 0 = Flexural-torsional restraint is not provided
  • 1= Flexural-torsional restraint is provided along the length.
FU 345.0 MPa Ultimate strength of steel.
FYLD 300.0 MPa Yield strength of steel.
KT 1.0 K value for flexural torsional buckling.
KY 1.0 K value for general column flexural buckling about the local Y-axis. Used to calculate slenderness ratio.
KZ 1.0 K value for general column flexural buckling about the local Z-axis. Used to calculate slenderness ratio.
LAT 0

Specify lateral support conditions:

  • 0 = Beam is laterally unsupported.
  • 1 = Beam is laterally supported.
LEG 0

This parameter is meant for plain angles (clause 13.3.3.2).

  • 0 = The angle is connected by the longer leg.
  • 1 = The angle is connected by the shorter leg.
LT Member Length Length for flexural torsional buckling.
LY Member Length Length for general column flexural buckling about the local Y-axis. Used to calculate slenderness ratio.
LZ Member Length Length for general column flexural buckling about the local Z-axis. Used to calculate slenderness ratio.
MAIN 200 Allowable slenderness limit for compression members. A value of 1 suppresses this check. Any value greater than 1 is used as the compression slenderness check value. A value of zero (0) uses the default (i.e., slenderness limit of 200).
NCR 0 This parameter sets the n factor to calculate Cr value as per clause number 13.3.1
  • 0 = 1.34
  • 1 = 2.24
Notes:
  1. The default value of n is used for all sections.
  2. n = 2.24 for Hollow sections (e.g., HSST, HSSP, Pipe Tube), for doubly symmetric built-up (STP = 2) sections (e.g., W, M, S, HP sections), and for Welded Wide Flange (WWF) sections if NCR is set to 1. WWF sections are designed as built up sections.
  3. n = 1.34 for doubly symmetric hot rolled sections and for single symmetric hot rolled or built-up sections (e.g., Channel, Tee, Angle) regardless of the NCR parameter value.
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 the design strength.
SLF 1.0 The shear lag factor, U, normally taken from Cl. 12.3.3.2, combined with the NSF parameter to determine the rupture strength.
SNUG 1

Specify type of connection for the built-up members (Refer to Cl. 19.1.4):

  • 0 = Welded or pretensioned bolts.
  • 1 = Bolted snug-tight.
SSY 0
  • 0 = Sway or Unbraced along local Y axis
  • 1 = Braced along local Y axis
This parameter is required to choose the proper value of U1y which is used to determine the cross-sectional strength, overall member strength and lateral torsional buckling strength. Refer to Axial compression and bending for details.
SSZ 0
  • 0 = Sway or Unbraced along local Z axis
  • 1 = Braced along local Z axis
This parameter is required to choose the proper value of U1z which is used to determine the cross-sectional strength, overall member strength and lateral torsional buckling strength. Refer to Axial compression and bending for details.
STIFF Member length of depth of beam, whichever is lesser. Spacing of traverse stiffeners.
STP 1
  • 1.0 = Rolled section
  • 2.0 = Welded built-up section
TMAIN 300 Allowable slenderness limit for tension members. A value of 1 suppresses this check. Any value greater than 1 is used as the tension slenderness check value. A value of zero (0) uses the default (i.e., slenderness limit of 300).
TRACK 0.0

Design output:

  • 0.0 = Report only minimum design results.
  • 1.0 = Report design strengths also.
  • 2.0 = Provide full details of design.
UNB Member Length Unsupported length in bending compression of the bottom flange for calculating moment resistance.
UNT Member Length Unsupported length in bending compression of the top flange for calculating moment resistance.
Parent topic: D4.E. Canadian Codes - Steel Design per CAN/CSA-S16-09/14