Applies To
	Product(s):	STAAD.Pro
	Version(s):	All
	Environment:	N/A
	Area:	STAAD.Pro Analysis Solutions
	Subarea:	Seismic Analysis
	Original Author:	SANJIB DAS, Global Technical Support Group

There can be many situations as shown below where effective base dimension(d) has to be computed for calculation of approximate natural time period of the structure using equation of clause 7.6.1 (C). The conditions are shown below-

Thus, in IS1893(Part-1)-2016 seismic definition in STAAD.Pro CE there are two parameters available to define base dimension in X and Z using DX and DZ parameter.