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

 

If a Floor Diaphragm is modelled to represent a slab entity, is the weight of the slab automatically accounted for if we specify the SELFWEIGHT load item?

 

No. Note that Floor Diaphragm is not an actual physical entity. The height at which the floor diaphragm is defined only helps in linking the master node with all other nodes at that level using SLAVE ZX entity. The Master node is located at the center of mass of that floor, calculated from the mass data in the reference load case. The Rigid Diaphragm only ensures the inplane rigidity of the slab to be accounted for in the analysis.

Thus, the self-weight of the slab needs to be separately specified as floor loads or equivalent member loads on the beams forming the slab panels.