Range of seismic load

[g.borre]

Hi,
where can I define the range of seismic load in a seismic analysis with italian code?
I would like to neglect the masses of the underground floors.
Thanks

[Artur.Kosakowski · Accepted solution]

1. Set disregard density in the parameters of the modal analysis

2. Define self-weight on the 'above the ground' part of a model

3. Convert this load case into mass

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[g.borre]

thank you Artur!

[g.borre]

sorry but I have a doubt...

1. ok

2. I create a new load case (self weight on the above the groung part of model)

3. analisys type --> load to mass conversion and I add the new case in the table

in this way I have two load case with self weight (one with total structure and one with the above the ground part of model).

may I exclude the new case from the load case code combination table? is it correct?

many thanks

[Artur.Kosakowski]

Use the self-weigh for the whole model in definitions of combinations and the part of the model one for load to mass conversion to define masses which take part in dynamics.

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[structural.engineer79]

Mr Artur

1- Disregard density this mean we neglect the self weight of structure.

2- If i defined one dead load case DL1 and I select Disregard density , from load to mass conversion if I select DL1 this meaning the self weight of structure will not consider in Seismic analysis only dead load value will consider.

3- If I defined two type of dead load  DL1 and DL2. DL1 for self weight and DL2 for other dead load excluding self weight. If select disregard density in modal analysis and select DL1 and DL2 in load to mass conversion this meaning DL1 its Ignored and this will be same if I select only DL2 in load to mass conversion without click disregard density.  

this is correct or no ? 

[Rafacascudo]

Robot will, by default, consider the mass of all your bars, panels , and solids even if you have not defined a " generated self weight " load case.
When you select to disregard density then Robot will not consider any masses at all.
This allows you to choose which objects you want to have their masses considered by converting custom load cases to mass