hi sir,
I am performing a response spectrum analysis for a steel structure.
Objective: To qualify the steel structure for MCE condition as per IS 1893. As per the IS 1893 code, the damping ratio to be considered for the steel material is 4%.
Available ground spectra for analysis are at 5% damping.
Clarification: Whether STAAD internally interpolates the ground spectrum data of 5% damping to material damping required for the analysis?
For understanding, individual analysis is done with 4% & 5% damping values in the Response Spectrum dialog box. The results for the peak storey shear with 4% and 5% damping are attached, whether this confirms that STAAD internally interpolates the spectrum data.
Kindly clarify
Fullscreen peak storey shear with 4% damping.txt Download 4% damping MODE ACCELERATION DAMPING 1 1.54866 0.04000 2 2.27843 0.04000 3 2.32859 0.04000 4 2.62683 0.04000 5 2.67598 0.04000 6 2.67598 0.04000 7 2.67598 0.04000 8 2.67598 0.04000 9 2.67598 0.04000 10 2.67598 0.04000 11 2.67598 0.04000 12 2.67598 0.04000 13 2.67598 0.04000 14 2.67598 0.04000 15 2.67598 0.04000 16 2.67598 0.04000 17 2.67598 0.04000 18 2.67598 0.04000 19 2.67598 0.04000 20 2.67598 0.04000 21 2.67598 0.04000 22 2.67598 0.04000 23 2.67598 0.04000 24 2.67598 0.04000 25 2.67598 0.04000 26 2.67598 0.04000 27 2.67598 0.04000 28 2.67598 0.04000 29 2.67598 0.04000 30 2.67598 0.04000 31 2.67598 0.04000 Fullscreen peak storey shear with 5% damping.txt Download 5% damping MODE ACCELERATION DAMPING 1 1.44682 0.05000 2 2.12860 0.05000 3 2.17546 0.05000 4 2.45409 0.05000 5 2.50000 0.05000 6 2.50000 0.05000 7 2.50000 0.05000 8 2.50000 0.05000 9 2.50000 0.05000 10 2.50000 0.05000 11 2.50000 0.05000 12 2.50000 0.05000 13 2.50000 0.05000 14 2.50000 0.05000 15 2.50000 0.05000 16 2.50000 0.05000 17 2.50000 0.05000 18 2.50000 0.05000 19 2.50000 0.05000 20 2.50000 0.05000 21 2.50000 0.05000 22 2.50000 0.05000 23 2.50000 0.05000 24 2.50000 0.05000 25 2.50000 0.05000 26 2.50000 0.05000 27 2.50000 0.05000 28 2.50000 0.05000 29 2.50000 0.05000 30 2.50000 0.05000 31 2.50000 0.05000 32 2.50000 0.05000
4% damping MODE ACCELERATION DAMPING 1 1.54866 0.04000 2 2.27843 0.04000 3 2.32859 0.04000 4 2.62683 0.04000 5 2.67598 0.04000 6 2.67598 0.04000 7 2.67598 0.04000 8 2.67598 0.04000 9 2.67598 0.04000 10 2.67598 0.04000 11 2.67598 0.04000 12 2.67598 0.04000 13 2.67598 0.04000 14 2.67598 0.04000 15 2.67598 0.04000 16 2.67598 0.04000 17 2.67598 0.04000 18 2.67598 0.04000 19 2.67598 0.04000 20 2.67598 0.04000 21 2.67598 0.04000 22 2.67598 0.04000 23 2.67598 0.04000 24 2.67598 0.04000 25 2.67598 0.04000 26 2.67598 0.04000 27 2.67598 0.04000 28 2.67598 0.04000 29 2.67598 0.04000 30 2.67598 0.04000 31 2.67598 0.04000
5% damping MODE ACCELERATION DAMPING 1 1.44682 0.05000 2 2.12860 0.05000 3 2.17546 0.05000 4 2.45409 0.05000 5 2.50000 0.05000 6 2.50000 0.05000 7 2.50000 0.05000 8 2.50000 0.05000 9 2.50000 0.05000 10 2.50000 0.05000 11 2.50000 0.05000 12 2.50000 0.05000 13 2.50000 0.05000 14 2.50000 0.05000 15 2.50000 0.05000 16 2.50000 0.05000 17 2.50000 0.05000 18 2.50000 0.05000 19 2.50000 0.05000 20 2.50000 0.05000 21 2.50000 0.05000 22 2.50000 0.05000 23 2.50000 0.05000 24 2.50000 0.05000 25 2.50000 0.05000 26 2.50000 0.05000 27 2.50000 0.05000 28 2.50000 0.05000 29 2.50000 0.05000 30 2.50000 0.05000 31 2.50000 0.05000 32 2.50000 0.05000
If you check STAAD.Pro Help manual, it is explained, please refer to the attached screenshot