pinching in infilled frame

[sm.emami]

Dear All,

I want to calibrate an masonry infilled RC frame with Seismostruct. For this purpose, I use the static time history analysis. I have a problem with the pinching in the hystersis behavior of the result. Infact the pinching in the analytical model is more than experimental one. How can I reduce the pinching in my model?

Thank you in advance.

sm.emami

[gemini]

increase the concrete cover