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

In the member end forces output, why are two values being reported for axial forces? Also, why is it that sometimes the numerical values of these two are the same and sometimes they are not?

There are two values because member end force output consists of the forces and moments at the start node as well as at the end node of the member.

At the start node, a positive value of the axial force indicates axial compression, and a negative value indicates axial tension. At the end node, a positive value indicates axial tension, and a negative value indicates axial compression.

Generally, if the values at the start and at the end are not the same in magnitude, it is due to a load acting along the local X axis of the member. A typical example of this is a column (vertical member) subjected to selfweight loading. The difference in magnitude of the axial forces at start and end should be equal to the load acting along the local X axis of the member.