Time period error

Question:

Kindly help us in finding the error in calculation of time period, Seismic analysis.

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Answer:Hello sir,

Kindly note the deformations in the final construction stage. The dummy elements undergo huge deformations and that gives rise to instability. It isn't advisable to use dummy elements with very low stiffness in models where dynamically sensitive analysis are performed. This affects the eigen value analysis as well. Kindly remove these dummy elements or provide those a suitable stiffness values. On changing their size to about 1mx1m, the results are fine.