Modelling of flexible floor diaphragms in URM buildings

[pcandeias]

I am currently using SeismoStruct 2021 (release 3, build 2) to model a URM building with flexible floor diaphragms. I can only find references in the user manual and examples in the sample models webpage for URM buildings with rigid floor diaphragms. Any ideas how to simulate flexible floor diaphragms?

[seismosoft]

One way to model flexible floor diaphragms is to employ the penalty functions for rigid constraints (it is the default method anyway), by reducing the exponent of the penalty coefficients of diaphragms (Program Settings>Constraints). Another way is to simply ignore the effect of the diaphragms.
Seismosoft Support

[pcandeias]

Thank you for the response. I have two more questions and a request for the developers:

- Is there any rule of thumb to adjust the penalty coefficients of the diaphragms for a given floor stiffness?

- Going either way, it means that both the vertical loads and the inertial masses/loads have to be distributed "by hand" on the masonry spandrels?

- Now that SeismoStruct includes structural elements for masonry buildings, it would be nice to have a shell element with elastic orthotropic behaviour to simulate timber floors as these are very common in old URM buildings.

[seismosoft]

-We cannot propose any rule of thumb for the adjustment of the penalty coefficients.
-Yes, unless you employ the Building Modeller to model your structure (the BM automatically distributes the slab forces to the beams and columns in the perimeter). All the same the Building Modeller does support only RC buildings for the time being
-SeismoStruct v2023 features an elastic shell element.
Seismosoft Support

[pcandeias]

Thank you for your reply. I will check SeismoStruct v2023.

[Cianmc345]

I am trying to simulate CLT panels on seismostruct, I am wondering if you could give me some guidance how best to achieve this

Kind Regards
Cian

[seismosoft]

Although SeismoStruct does not have specialized modules/features for timber structures, you could employ the shell4 elastic element for the modelling, employing appropriate parameters for the timber.
Seismosoft Support