one way or two way slab modeling

[a.nikpour]

Hi.
How can I modeling one way slab (such as concrete joist) or two way slab in seismostruct?

[seismosoft]

In SeismoStruct slabs are modelled as rigid diaphragms and additional loads on the supporting beams. If you are using the Building Modeller, you can select the slab and you may choose the supporting conditions on the Member Properties on the right of the screen.
Seismosoft Support

[a.nikpour]

Thank you.
So by changing support conditions we can change the slab performance ( For example, if we choose 4 beams around the slab, slab working as a two way slab ), but we model the concrete joist as semi rigid diaphragm. I don't know how we should model the semi rigid diaphragm?

[z.gronti]

Dear a.nikpour,

Slabs are modelled in SeismoStruct as rigid diaphragms that connect the beams, columns and walls in their perimeter and as additional loads applied to the beams. If you use the Building Modeller and modify the slab's supporting conditions, the slab will still be modelled in SeismoStruct as ridig diaphragm but its additional load will be assigned only to the supporting beams.

[seismosoft]

In general semi rigid diaphragms are modeled with plane elements that are not currently available in SeismoStruct. We are currently programming a set of elastic 2D elements that will probably be available in SeismoStruct v2019.
Seismosoft Support

[a.nikpour]

I found out we can't model the semi rigid diaphragm and it has destructive effect on latral load distribution where we have semi rigid diaphragm. Whats your suggestion for this issue?

[seismosoft]

The fact that you have a semi rigid slab means that the lateral loads cannot be redistributed around the floor. Probably, you need to distribute the lateral loads around the floors, rather than concentrating them at one side of the building.
Seismosoft Support