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D1.I.1.4 Design Parameters

Design parameters are summarized in the table shown later in this section.  These parameters may be used to control the design process to suit specific modeling needs.  The default parameter values have been selected such that they are frequently used numbers for conventional design.

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. Steel Design Parameters for ASCE 10-97
Parameter Name Default Value Description
CODE -

Must be specified as ASCE to design per ASCE 10-97.

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

BEAM 1.0

0)  Perform design at beam ends and section locations specified according to the SECTION command

1)   Perform design at the ends and eleven intermediate sections of the beam

CMY

CMZ

0.85 for sidesway and calculated for no sidesway Cm value in local y and z axes as defined in equation 3.12-1 on p.10 of ASCE 10-97.
DMAX 45.0 in. Maximum allowable depth for member selection
DBL 0.75 in. Diameter of bolt for calculation of number of bolts required and the net section factor.
DMIN 0.0 in. Minimum allowable depth for member selection
ELA 4

Indicates what type of end conditions are to be used from among Equations 3.7-4 thru 3.7-7 to determine the KL/R ratio.

  • 1) EQN.3.7-4, Page 4
  • 2) EQN.3.7-5, Page 4
  • 3) EQN.3.7-6, Page 4
  • 4) EQN.3.7-7, Page 5
Note: Value 1 is valid for leg members only.
ELB 1

Indicates what type of end conditions are to be used from among Equations. 3.7-8 thru 3.7-10 and 3.7-12 thru 3.7-14 to determine the KL/R ratio.

  • 1) EQN.3.7-8, Page 5, EQN.3.7-12, Page 5
  • 2) EQN.3.7-9, Page 5, EQN.3.7-13, Page 5
  • 3) EQN.3.7-10, Page 5, EQN.3.7-14,Page 5
FVB 30 KSI Shear strength of bolt.
FYB 36 KSI Yield strength of bolt.
FYLD 36.0 KSI Yield Strength of steel
KT 1.0 Effective length coefficient for warping restraint (clause 3.14.4, p. 11)
KY 1.0 Effective length factor (K) for compression buckling about the Y-axis (minor axis)
KZ 1.0 Effective length factor (K) for compression buckling about the Z-axis (major axis)
LEG 0.0

This parameter is meant for plain angles.

  • 0) indicates that the angle is connected by both legs and allowable stress in axial tension is 1.0FYLD.
  • 1) indicates that the angle is connected only by the shorter leg and allowable tensile stress is computed per clause 3.10.2 as 0.9FYLD.
  • 2) indicates that the angle is connected by the longer leg.
LT Member Length Effective length for warping.
LY Member Length Length to calculate slenderness ratio for buckling about the Y-axis (minor axis)
LZ Member Length Length to calculate slenderness ratio for buckling about the Z-axis (major axis)
MAIN 2

Parameter that indicates the member type for the purpose of calculating the KL/R ratio  (see clause 3.4, PAGE 3, ASCE 10-97)

  • 1) Leg member, KL/R ≤ 150
  • 2) Compression member, KL/R ≤ 250
  • 3) Tension member, KL/R ≤ 500
  • 4) Hanger member, KL/R ≤ 375 (Clause 3C.4, page 31)
  • 5) Redundant member, KL/R ≤ 250
  • 10) Do not perform the KL/R Check
NHL 0 Number of bolt holes on the cross section that should be used to determine the net section factor for tension capacity.
NSF 1.0 Net section factor for tension members
RATIO 1.0 Permissible ratio that determines the cut off point for pass/fail status. A value below this quantity indicates PASS while a value greater than this quantity indicates FAILURE.
SSY 0.0

0) Sidesway in local y-axis

1) No sidesway
SSZ 0.0 Same as above except in local z-axis
TRACK 0.0

0) Suppresses printing of allowable stresses

1) Prints all allowable stresses

2) Prints expanded output
UNB Member Length Unsupported length 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 of the top flange for calculating flexural strength. Will be used only if flexural compression is on the top flange.
Notes:
  • All values must be provided in the current unit system.
  • If ELA and ELB are both defined for a member, only one of them will be used for the slenderness calculation depending on the member type (as defined by the MAIN parameter) for that member.
Parent topic: D1.I.1. American Transmission Tower Code - Steel Design per ASCE 10-97