Time history analysis got same result with different model

[tthdl]

I built a 2d 3 story 2 bay RC frame. Then I run the time history analysis. The model runs good, everything seems fine. But then, I reinforced the structure with extra FRP materials and run the time history analysis, I got the same results as the un-reinforced model. At first I thought was the gravity load was to small so the structure won't damage. But after I change the model to a 8 story 2 bay RC frame, I still get the same results. So I'm confused. Is there anyone may tell me what went wrong? Thanks in advance.

[selimgunay]

The ground motions that you are using in time history analysis could be small that does not result in inelastic response.

[tthdl]

Thank you very much for replying! I did try stronger ground motion, but still got same result

[selimgunay]

It could be possible that the units of the ground motion file could be different (like g's), whereas the model unitc could be in inch. So, the larger motion that you think you are applying could still be a small motion.