CFS Version 5 Changes
Released November 2005
2004 North American Specification
CFS now supports the 2004 Edition of the "North American Specification for the Design of ColdFormed Steel Members".
This includes ASD and LRFD for U.S. and Mexico, as well as LSD for Canada. CFS continues to support the 2001 North American
Specification and the 1996 AISI Specification with the Supplement 1 (1999). Specific changes from 2001 to 2004 are as follows:
 Revision to list of applicable steels
 Limit on strength increase from coldwork of forming
 Revision to effective width of stiffened elements with circular holes
 Revision to effective width of unstiffened elements under stress gradient
 Revision to flexural members not subject to lateraltorsional buckling
 Revision to combined bending/shear interaction equations
 Revision to web crippling coefficients for multiweb deck sections
 Revision to combined bending/web crippling interaction equations
Direct Strength Method
The 2004 Specification includes an appendix for the Direct Strength Method.
This method provides an alternate design procedure to portions of the main specification.
It utilizes elastic critical buckling values to predict axial and bending strengths of a member.
CFS version 5 includes the following changes to support this method:
 The Section Inputs window contains a new tab for entering elastic buckling values
 The elastic buckling feature let's you assign buckling values directly to the section inputs
 The Strength and Member Check calculations use the Direct Strength Method if selected
Calculation Trace Feature
One of the major enhancements in CFS Version 5 is the ability to report detailed steps of the
internal calculations. This output includes the symbols used in the Specification, the values calculated,
and the equation numbers used to perform the calculations. The following trace options are available:
 Strength calculations
 Member check calculations
 Effective section properties
Other Enhancements
 Shareable licensing option which utilizes a USB or parallel port key
 Network capable sharing of this type of license
 Section Wizard remembers your previous inputs to make the next section easier
 New feature to report section and analysis inputs without having to print
 New feature to shift section parts so the origin is at the center of gravity
 Arrow keys may be used to change selected elements
 Input limits were relaxed for some values (yield strain, minimum lip, etc.)
 Analysis Wizard remembers your previous inputs to make the next analysis easier
 Analysis window has a new tab for storing your own notes about the analysis
 Analysis solver uses increased precision to improve calculated results
 Elastic buckling feature provides mode shape for every solved length
 Elastic buckling profile provides buckling values between solved points
Corrections
 Corrected shear yield limit check to apply only to stainless steel
 Corrected column buckling stress for pointsymmetric section connected to sheathing
 Corrected member check for unsymmetrical parts in builtup members with connector spacing > 0
 Corrected error that may occur when buidling section libraries on Windows XP
 The 2002 ASCE specification removed the compression strength reduction for unstiffened channels, zees, and angles
 Analysis diagrams – combinations with no transverse loads are excluded to avoid division errors
 Concentrated loads are shown at midpoint of load instead of left edge
 Analysis check points now include locations adjacent to concentrated loads
 Inflection points within cantilevers are now prohibited from being considered brace points
 Corrected analysis bracing check on unsymmetrical section
 Corrected web crippling calculations when analysis supports have different settings for fastened flanges
 Fixed output format for analysis loads
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