Thank you for the explanation, sir. I have a question regarding Modal Analysis. Even when we are performing Linear Static Analysis in ETABS and we haven't defined Modal Case in Load Cases, we can still get results for different mode shapes of the building and other modal results. Is there any sifnificance for Modal Results in Linear Static Analysis? Should we check and verify for differnt mode shapes and modal particiapting mass ratios for this type of analysis? I hope I made you my question clear.
@@UnderstandingStructures i get it thanks sir. There is another question that the limitation given by the building codes in terms of weak storey, soft storey, mass irregularity, re-enterant corners, and max eccentricity of 15% are limited to ELF procedure only? Can structures with above imperfections be designed using modal analysis?
If you are performing design, it would be better to modify the geometry (the distribution of mass and stiffness) such that you avoid the first torsional mode. If you are evaluating the existing building, then perform detailed seismic performance evaluation to check whether the building need any bracing, strengthening etc. under anticipated seismic hazard level.
![Part 1 - CSI ETABS Basic Demonstration - Concepts of Structural Idealization [Urdu Language]](http://i.ytimg.com/vi/HeaqP0-Iw-Q/mqdefault.jpg)
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Good brother....
waiting for your more videos
Thank you for sharing knowledge.
Thank you very much sir...your video lectures are very informative and you explain things very well
Asslamualikum sir. Amazing sir.
Excellent explaination.
Glad it was helpful!
Sir please ek video development of fragility curve for Rc building ke upar banayea we all Indian students are waiting for your video on this topic.
Thank you for the explanation, sir. I have a question regarding Modal Analysis. Even when we are performing Linear Static Analysis in ETABS and we haven't defined Modal Case in Load Cases, we can still get results for different mode shapes of the building and other modal results. Is there any sifnificance for Modal Results in Linear Static Analysis? Should we check and verify for differnt mode shapes and modal particiapting mass ratios for this type of analysis? I hope I made you my question clear.
During a seismic excitation of a MDOF system the modes with lower contribution will appear first followed by the larger contribution modes?
No. The first mode have highest contribution in the dynamic displacement response. The contribution of higher modes is less.
@@UnderstandingStructures i get it thanks sir.
There is another question that the limitation given by the building codes in terms of weak storey, soft storey, mass irregularity, re-enterant corners, and max eccentricity of 15% are limited to ELF procedure only? Can structures with above imperfections be designed using modal analysis?
What if structural frame is not regular and torsion mode comes in first mode ?
If you are performing design, it would be better to modify the geometry (the distribution of mass and stiffness) such that you avoid the first torsional mode. If you are evaluating the existing building, then perform detailed seismic performance evaluation to check whether the building need any bracing, strengthening etc. under anticipated seismic hazard level.