I hope this paper will be useful for you.

https://core.ac.uk/download/pdf/10895497.pdf

In most of the design of framed structures time period of vibrations is calculated on the basis of infilled frame and other bare frames which affect the calculation of spectral acceleration value in the design and calculation of pseudo seismic coefficient.

Secondly infilled frame structures response reduction factor will be different from bare frame and as such this will also affect calculation of seismic coefficient.

Cumulatively both are affecting calculation of seismic force on such structures.

Dear Abdelkader Nour,

From my extensive experience in analysis and design of frame buildings with shear walls I can tell you that non-structural elements (like infilled with stone masonry, bricks, or concrete blocks) are increasing the initial horizontal stiffness of the overall structure by about 25% on average. This must be taken into account in order to correctly calculated the period of vibrations of the building in the elastic stage. Otherwise your analysis and the magnitude of the calculated value of the period, as well as seismic forces will be wrong.

However, infilled materials have brittle mode of destruction (see the below table for the 9-story building)

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Overall hysteresis loops including influence of shear walls, columns, and non-structural elements for each floor;

Hysteresis loops showing behavior of shear walls for each floor;

Hysteresis loops showing behavior of columns for each floor;

Hysteresis loops showing behavior of non-structural elements for each floor.

Best regards,

Prof. Dr. Mikayel Melkumyan (Armenia)

Mikayel Gregor Melkumyan, Thank you very much for giving importance to my question and thank you for the important answer.