Seismosoft | Earthquake Engineering Solutions

Hello,
I have a problem that when I do both analysis for the same 15-storey building. I get different modal periods, like one of them is 1.5s and the other 2.9s. What can be cause this issue?
I give 1 units of force as incremental load to every node beneath surface. Used craked stiffness and only beams have 0 as rigid end zone values.

Dear seljuk,

Could you please check if you use the current version of SeismoStruct v2022-Release 3-Build 25?

In case you already use the current version, could you please check if you have set the same percentages for the cracked stiffness in both of your projects (i.e. the eigenvalue and the static pushover analysis files)?

If you have checked all the above and you still have problems with the results, please send me your files at z.gronti@seismosoft.com to take a look at them.

Depending on the selected Standard, the eigenvalue analysis of the pushover analysis should employ the cracked or the uncracked stiffness. In particular in the European (EC8, Part-3) the American Codes (ASCE 41) the uncracked stiffness should be employed (and in employed in SeismoStruct).
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