Seismosoft | Earthquake Engineering Solutions

By residual strength, I understand that upon reaching the performance criteria , the strength will be reduced to a specific percentage of the peak strength. I meant to ask if SeismoStruct has an option to input the particular percentage associated with residual strength. If not, what is the default value associated with residual strength in SeismoStruct. Also, is the drop in strength sudden or is there a defined value of negative stiffness associated with this drop.

Yes, you can specify the percentage of drop. This is done inside the form for the definition of the performance criterion, see the programs documentation for this. The drop is sudden.
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