Applies To
	Product(s):	STAAD.Pro
	Version(s):	ALL
	Environment:	ALL
	Area:	Modeling Solutions
	Subarea:	Specifications
	Original Author:	Abhisek Mandal, Bentley Technical Support Group

 

When I run the IS 1893 static loading on a model with Rigid Diaphragms specified, I encounter the following error message. What does this error message mean?
***ERROR- ACCIDENTAL LOAD SHOULD NOT BE DEFINED IN SEISMIC DEFINITION ON MODELS WITH RIGID FLOOR DIAPHRAGMS. USE DEC AND ACC FACTORS ONLY.

 

This is because you have specified the Accidental Load with IS 1893 definition. This should not be done when you have specified the Rigid Diaphragm. In such situations, the Accidental Load should be defined as ACC in the following format.

 

1893 LOAD { X | Z } (f₁) (DECCENTRICITY f2 ) (ACCIDENTAL f₃)

 

Please refer to the following link for further information:

https://communities.bentley.com/products/structural/structural_analysis___design/w/structural_analysis_and_design__wiki/21193.torsion-consideration-in-is-1893-2002-seismic-analysis