Further orthotropic slab modeling considerations
When modeling two-way spanning slabs exhibiting strong orthotropic behavior, there are situations that need to be carefully considered. These include, among others: (i) openings, (ii) free edges perpendicular to the principal direction of the slab item, (iii) cantilevers in the weak direction of the slab item, and (iv) concentrated points of load or support. All those cases, if not modeled correctly, can lead to unexpectedly large deflections and nodal instabilities.
Openings
Creating an opening not supported by any additional beams can lead to increased deflections around the perimeter of the opening.
Free edges
Having an orthotropic slab with an unsupported edge perpendicular to the principal direction of the slab can lead to extreme deflections along that edge.
Cantilevers
Strongly orthotropic slabs are unable to maintain stability if only supported along one of the edges perpendicular to the weaker direction of the slab.
Point loads and supports
Supporting an orthotropic slab by point supports or applying concentrated point loads can lead to increased deflections around the point of loads/supports