Infill walls-gravity loads

[TUC]

When infill walls are used to model a RC frame they should not carry any vertical load (dead or moving) because they are constructed after the bearing structure (RC frame) so the later is actually carrying the total amount of these loads. Can the option of Time L.F be used in this case? (maybe an activation time should be somehow assigned to the infill elements?).
I am not much familiar with this function, so I am asking: does the Activation-Deactivation Time L.F corresponds to the time step in case of Time history analysis and load factor in case of push over (the minus values are used for the static time history analysis)? In order this option to be properly used, should we make first an analysis to obtain the Time L.F that corresponds to the desired state of the element and then make the final analysis using the (obtained from the initial analysis) values of Time L.F to assign them at these elements?

Regards

[seismosoft]

TUC,

In the Help System/User Manual of SeismoStruct it is explicitly written:

"Note that strength and stiffness of the infills are introduced after the application of the initial loads, so that the former do not resist to gravity loads (which are normally absorbed by the surrounding frame, erected first). If users wish their infills to resist gravity loads, then they should define the latter as non-initial loads."

Seismosoft Support

PS: for what concerns your questions on the Activation/Deactivation time, you are certainly on the right track, and with a few trial runs you will certainly gain a full grip on the way this feature works..

[TUC]

Thank you for the reply.
Sorry, I didn't notice that description on the help topic...

Regards

[TUC]

If you don't mind, i would like to ask for a suggestion about a similar issue.
When braces are used in a structure for retrofiting purposes, the braces should not carry any of the gravity loads. In such case can we use the option Time L.F (activation - deactivation of brace elements) or is it maybe any other kind of simulation more proper to use instead (e.g with link elelemnts with proper responce curves assigned)?

Just a guidance by experience from anyone that has faced such an issue in order to know if by using the Time L.F option i am in the right way...

[seismosoft]

We would probably go for the use of the 'Activation L.F.' feature, noting however that not all cases are the same, and one may indeed find a structure where the employment of a link element featuring a response curve with an initial displacement slack may be better (in terms of numerical stability).

But, we repeat, in principle, the 'Activation L.F.' is the most appropriate approach for modelling repair/retrofitting, and was introduced exactly for such type of modelling requirements.

Seismosoft Support

[TUC]

Thanks a lot..