Applies To
	Product(s):	STAAD.Pro
	Version(s):	All
	Environment:	N/A
	Area:	Design
	Subarea:	American Steel Design
	Original Author:	Bentley Technical Support Group

In the output for steel design, what does the term "dff" represent?

"dff" is the value of actual length divided by local deflection. The actual length value is the distance between the nodes DJ1 and DJ2 which default to the actual end nodes of the member. The deflection used is the maximum local deflection between the points DJ1 and DJ2. You can get the Max. Local Displacement value by looking at the output of the PRINT SECTION DISPLACEMENT command. The definition of DFF, DJ1 and DJ2 may be found in Table 1 of STAAD.Pro Help section Design > D. Design Codes > D1. American Codes > D1.A. American Codes - Steel Design per AISC 360 Unified Specification > D1.A.6 Design Parameters.