No of cycles in displacement graph higher in dynamic analysis then the experiment

[Prafullamalla]

I am doing a dynamic analysis of building with bolted connection and comparing a result with the shake table test. The frequency of model matches with the experiment result and is 4Hz. but in the acceleration and displacement graph of model , no of cycles of acceleration and displacement equals to the frequency of the building, whereas in the experiment no of cycles of acceleration and displacement is 1 or 2. what might be the reason?

https://onedrive.live.com/?cid=64E85C63 ... ot&o=OneUp

[Prafullamalla]

Ok, the damping coefficient affects it. with increaing alpha for initial mode i.e., mass proportional, no . of frequency for displacement can be decreased but now, the amplitude is increasing

[Prafullamalla]

Because of Damping, now my curve matches with the experimental result but still I could not understand, why the experimental result is not similar to the model result. Check the fig. i.e., exp curve is smooth but my model has ups and down curve matching the fundamental frequency of building
Fig is in link below
https://onedrive.live.com/?cid=64E85C63 ... ot&o=OneUp