Applies To
	Product(s):	STAAD Advanced Concrete Design
	Version(s):	Connect Edition
	Environment:
	Area:	Concrete Design
	Subarea:	General
	Original Author:	Abhisek Mandal, Bentley Technical Support Group

Finding following error when we go to RCDC from ram structure / ram concrete: RCDC:File contains Steel columns & Concrete columns at lowest levels . Thus, could not proceed"When trying to open RCDC from Ram Concrete- Column: encountered an improper argument
.

In RCDC there are 2 approaches for columns. If the columns are made of concrete, RCDC designs them as column. If the columns are made of steel and supports are just below them RCDC detects them as steel column and enter in pedestal design module. Now, in your case as both steel and concrete column is at support level, program fails to decide in which module it will go and throws such warning.
As workaround you can model a concrete column just below the steel columns of very small length. In reality also there will be pedestal under steel column and you can model the same also. Once you model a concrete column below the steel columns and place support below that concrete column, RCDC will work fine.