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Saturday, 9 June 2018

Seismic Analysis of Structures by Manual, Staad, ETABS, etc. | SD3 Archieve

Did a Seismic Analysis of structure to find the loading and the stresses generated in the structure, as per the syllabus of Pune University we were supposed to do a manual analysis using the IS Codes for Seismic Design.

As per the requirement, we did the manual calculation. By manual I mean I coded an Excel sheet for the purpose as it becomes easy to modify the data and verify the conditions in excel by using the formulas.
Check out the spreadsheet below

This was quite of a difficult task, but with excel it became easy as much of the calculations were done in the software itself so I didn't had to manually calculate on the calculator.

Also the seismic forces were calculated based on the lump mass theory and after using the excel sheet I got the seismic forces that were acting on the structure so I actually used Staad to do the work for me.
Check out the Article Below

Calculations of Moment using STAAD, replacing the Tedious Frame Analysis | SD3 Termwork

But then it wasn't accepted by the as per the university criteria so I had to do it manually so I coded a spreadsheet for the purpose. I just coded the spreadsheet once and then the same was used multiple times & I'd even calculated the forces in the frame for other teams in our college (that too within minutes)
Check out the Article Below

Substitute Frame Method for Analysis of Frame using Microsoft Excel | SD3 Termwork

But this was all done, and I was still confused if the forces that I calculated were correct or not, as the magnitude was way too large and the other teams had taken different structures were having comparatively low magnitude. Even the teachers at my college were not convinced if what I did was correct or wrong, I studied a few analogies and found that I was correct, as my building was not uniform and the size was also large so the seismic forces induced were also comparatively large. But I had to prove this to the examiner, as a solution I decided to put the same model to test on ETABS.

I did the modeling, applied the loading conditions and started the analysis.

This is how the structure reacted under seismic action

Finally, I got the design report from ETABS which is as follows:

After studying the report and comparing the calculations I did manually, I found that there was a difference of approximately 5-10% in both the values and the teachers at my college were convinced that what I did was correct.

This is how ETABS helped me verify my works, and I realized how fast the work could be done on structural design software.

Thanks for Reading

-Sayyed Shadaab
The Engineer for the Digital Civilization

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