The Steel Frame Design Preferences are basic assignments that apply to all of the steel frame members. Tables B-1, B-2, and B-3 list Steel Frame Design Preferences for “AISC 360-10.” Default values are provided for all preference items. Thus, it is not necessary to specify or change any of the preferences.
However, at least review the default values to ensure they are acceptable. Some of the preference items also are available as member specific overwrite items.
The Overwrites are described in Appendix C. Overwritten values take prece-dence over the preferences.
Table B-1: Steel Frame Design Preferences
Item Possible Values Default Value Description
Design Code Design codes
available in the current version
The selected design code. Subsequent design is based on this selected code.
Time History Design Envelopes, Step-by-Step, Last Step, etc.
Envelopes Toggle for design combinations that include a time history designed for the envelope of the time history, or designed step-by-step for the entire time history.
If a single design combination has more than one time history case in it, that design combination is designed for the envelopes of the time histories, regardless of what is specified here.
Table B-1: Steel Frame Design Preferences
Item Possible Values Default Value Description
Framing Type SMF, IMF,
OMF, SCBF, OCBF, OCBFI, EBF
SMF This item is used for ductility considerations in the design, when seismic provisions are considered.
Seismic Design
Category A, B, C, D, E, F D This item varies with the Seismic Hazard Exposure Group and the Effective Peak Velocity Related Acceleration.
Design Provision ASD, LRFD LRFD Application provisions for calculation of
allowable/design and required strength of individual elements. Selection of ASD will enable additional fields for safety factor overwrites, whereas selection of LRFD will enable additional fields for resistance factors.
Analysis Method 7 Values Direct Analysis Method with General 2nd Order Analysis and
τb variable
Indicates the method used to check/design the steel members. The design module does not verify the acceptability of the selected design analysis method;
the user is expected to verify acceptability. Also, the user is expected to set the appropriate stiffness modification factors and to supply the combinations with appropriate notional loads.
Notional Load
Coefficient > 0 0.002 The coefficient used to define the notional load as a fraction of a given gravity load pattern.
Ignore Seismic Code? Yes, No No Toggle to consider (No) or not consider (Yes) the seismic part of the code in design.
Ignore Special
Seismic Load? Yes, No No Toggle to consider (No) or not consider (Yes) special seismic load combinations in design.
Is Doubler Plate Plug
Welded? Yes, No Yes Toggle to indicate if the doubler-plate is plug welded (Yes) or it is not plug welded (No).
HSS Welding Type ERW, SAW ERW Indicates the procedure used for welding the steel members.
Reduce HSS
Thickness? Yes, No Yes Toggle to consider if the HS (Box or Pipe) thickness is reduced (Yes) or should not be reduced (No).
Consider
Deflection? Yes, No No Toggle to consider the deflection limit (Yes) or to not consider the deflection limit (No).
DL Limit, L/ ≥ 0 120 Deflection limit for dead load. Inputting 120 means
that the limit is L/120. Inputting zero means no check will be made of this item.
Appendix B - 2
Table B-1: Steel Frame Design Preferences
Item Possible Values Default Value Description
Super DL+LL Limit, L/ ≥ 0 120 Deflection limit for superimposed dead plus live load. Inputting 120 means that the limit is L/120.
Inputting zero means no check will be made of this item.
Live Load Limit, L/ ≥ 0 360 Deflection limit for superimposed live load.
Inputting 360 means that the limit is L/360.
Inputting zero means no check will be made of this item.
Total Limit, L/ ≥ 0 240 Deflection limit for total load. Inputting 240 means that the limit is L/240. Inputting zero means no check will be made of this item.
Total-Camber Limit, L/ ≥ 0 240 Limit for net deflection. Camber is subtracted from the total load deflection to get net deflection.
Inputting 240 means that the limit is L/240. Inputting zero means no check will be made of this item.
Pattern Live Load
Factor ≤1.0 0.75 The live load factor for automatic generation of load
combinations involving pattern live loads and dead loads.
D/C Ratio Limit ≤1.0 0.95 The demand/capacity ratio limit to be used for acceptability. D/C ratios that are less than or equal to this value are considered acceptable. The program will select members from the auto select list with D/C ratios less than or equal to this value.
Maximum Number of Auto
Iteration ≥ 1 1 Sets the number of iterations of the analysis-design
cycle that the program will complete automatically assuming that the frame members have been assigned auto select sections.
Table B-2 Additional Steel Frame Design Preferences LRFD Provision
Item Possible Values Default Value Description
Phi (Bending) ≤1.0 0.9 Resistance factor for flexure.
Phi (Compression) ≤1.0 0.9 Resistance factor for compression.
Phi (Tension-Yielding) ≤1.0 0.9 Resistance factor for yielding in tension.
Phi (Tension-Fracture) ≤1.0 0.75 Resistance factor for tension rupture.
Phi (Shear) ≤1.0 0.9 Resistance factor for shear.
Phi (Shear, Short Webbed
Rolled I-Shapes) ≤1.0 1.0 Resistance factor for shear for specific short-webbed rolled I-Shapes.
Phi (Torsion) ≤1.0 0.9 Resistance factor for torsion.
Table B-3 Additional Steel Frame Design Preferences for ASD Provision
Item Possible Values Default Value Description
Omega (Bending) ≥ 1.0 1.67 Safety factor for flexure.
Omega (Compression) ≥ 1.0 1.67 Safety factor for compression.
Omega (Tension-Yielding) ≥ 1.0 1.67 Safety factor for yielding in tension.
Omega (Tension-Fracture) ≥ 1.0 2.00 Safety factor for tension rupture.
Omega (Shear) ≥ 1.0 1.67 Safety factor for shear.
Omega (Shear, Short
Webbed Rolled I-Shape) ≥ 1.0 1.50 Safety factor for shear for specific short-webbed rolled I-Shapes.
Omega (Torsion) ≥ 1.0 1.67 Safety factor torsion.
Appendix B - 4