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

Are the joint displacements (Inch, Radians) reported in example 11 the static displacements? If these are amplitudes (for example, at joint 5 for load case 2, X trans = 1.94384 inch) doesn't that mean this joint is failing in amplitude since it is very high?

For spectrum load cases, they are the absolute maximum displacement that those degrees of freedom will ever experience under the dynamic loading which that spectrum represents. In this example however, the numbers are so large only because the spectrum used is rather unrealistic. The spectral acceleration for mode 1 is 2.8g, which is unlikely even in the most intense earthquake.