The two options we’re talking about are 
and 
.
- If you only want to take the stiffness into account and not calculate the reinforcement, use .
It will allow you to easily take the weight gain due to the holes into account. - If you want to view stresses and/or calculate the reinforcement, use .
Besides the above mentioned difference, there is another difference regarding the torsional rigidity (= D66 in the stiffness matrix) :
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By default the torsional rigidity is neglected ( = the torsional factor is equal to 0%) to match beam-behaviour.
You can take the torsional ridigidy into account by entering a value for the torsion factor. |
By default the torsional rigidity is calculated using a torsion factor of 80%.
You cannot change the torsion factor. |
If you want both approaches to result in similar results, the torsional rigidity with should be set to 80%. A torsional factor of 80% also matches more the real life behaviour of a slab than 0%.
This plate type 
is not suitable for hollow-core-slabs since the upper and lower ‘flenge’ of the plate bear in two directions while a hollow-core-slab has a one-directional behaviour.
