Seismosoft | Earthquake Engineering Solutions

I want to verify several experimental RC member (beams and columns). I did it for RC columns with flexure failure simplicity without any link element or behavior curves (it means that springs were not considered). For verify RC column with shear failure, the verification did not successful and I was concluded that it needs to have link elements at the end and the start of the column with behavior curve (such as Takeda curve).
For RC beams, I didn't use any link element behavior curve, but my results, didn't match, for example the results was obtained like the following figure (red is for experimental results and blue is for seismostruct):

https://ibb.co/hcDkcF

I did it​ for several RC beams and I always had the results similarity, means the results graph of siesmostruct was broken earlier than the experimental results and had the final load bigger than the experimental. I change the loading phases or applied loading between response and load but the results were the same. I did several changes in the setting or material tab, but the results did not very different from the origin analysis. I used "infrm" elements and static push over analysis.
The considered experimental RC beams were failure in shear. I think that the different between my results and experimental results is because of the type of the failure. It means that for shear failure, it should be use link element at the start and the end of the beam. Please help me and send me recommends.

You mentioned in your post that in the graph the red line (i.e. the broken line) is for experimental results and blue is for SeismoStruct. However, on the second paragraph you mention that " the results graph of SeismoStruct was broken earlier than the experimental results". I am afraid that it is not clear which curve is for the test and which for the analysis. Further, all the inelastic frame elements in SeismoStruct are 'infrm'. You need to specify exactly which type of element you are using (infrmFB, infrmFBPH, infrmDB etc)
In any case note that in SeismoStruct (and any analytical package) shear is modelled indirectly. In SeismoStruct it is modelled through the shear capacity performance criterion. Use a similar performance criterion with residual strength, and you will get much closer to the observed behaviour.

Seismosoft Support

Thank you so much for your help. Red line is for experimenta results, blue is for seismostruct. InfrmFB was used for my member.
As mentioned in your post, I should define a shear criteria with residual stiffeness? Could you please give me for details because I have this problem with my column too and I don't have any idea for value of this residual stiffenesz

Hi simon1000,
Please refer to the manual and the help of the program, as well as the corresponding video on our YouTube channel.
https://www.youtube.com/watch?v=0ZCDciuq4Gg

Regards,
Seismosoft Support