How to add a sequence cyclic load (force then displacement Cycles) and obtain hysteresis curves ?

[Moh.Sarwat]

I am modelling a experimental test of steel coupling beam with cyclic loads to obtain (shear-strain and shear-chord rotation) hysteresis curves. I need help to know: How to add a sequence cyclic load start with force cycles following by displacement cycles to get this hysteresis loops ?

[seismosoft]

You can do this in two ways:
1) The easier is to use the static time-history analysis type, with a combination of force and displacement time-history loads. The force loading should be zero in the second part of the analysis and the displacement load should be zero in the first part of the analysis. Note however that this might not be feasible in the cases when the DOFs, where the displacement loads are applied in the second phase, need to be free to deform in the first part
2) With pushover analysis, using a sequence of load control and response control phases in opposite directions, i.e. (i) load control +X, (ii) load control -X, (iii) response control, +X, (iv) response control -X etc.

In any case, note that typically a static time-history analysis with displacement hysteretic loads should normally be sufficient in most cases of tests.
Seismosoft Support

[Moh.Sarwat]

Thank you for your quick response, I had tried the first way and i got a warning message at the beginning of the analysis said: "node n1_B4 is already loaded in the z direction.the last load in this direction is cancelled"

Attached are pictures for the assigned cyclic loads , and the warning message that i got
https://we.tl/t-bJJkINPmhi

This link is for the seismostruct model if you could check it and advice me for this issue
https://we.tl/t-mHcPAcdHvf

Thank you in advance

[seismosoft]

As I explained in my previous message, you cannot apply on the same DOF simultaneously a displacement and a force time history.
You might want to try with the pushover analysis with a sequence of phases.
Seismosoft Support

[kaysisig]

Hi there!

Does Seismostruct has a step-by-step tutorial on how to conduct a cyclic pushover analysis using sequence of load cases? I am new to this software and still exploring. I badly need this in doing a verfication model for an rc column subjected to slow cyclic loading.

[huffte]

You might try the Verification Report and associated SeismoStruct files. In particular, Chapter 4, Example 3 may be helpful. There are others which may suit your needs as well. The SeismoStruct YouTube videos may help too, though I am not sure if there is anything specific to cyclic pushover as I haven't investigated the YouTube channel extensively.

[seismosoft]

You can either use pushover analysis with a series of Response Control phases, or alternatively static time-history analysis with different loading curves.
Seismosoft Support