CSI ETABS - 07 - Stiffness Irregularity Check (Soft Story and Extreme Soft Story check)
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- เผยแพร่เมื่อ 11 ส.ค. 2019
- In this lecture, Stiffness Irregularity Check (Soft Story and Extreme Soft Story Irregularity check) as per ASCE 7-16 is discussed.
1- Stiffness Irregularity (soft story) excel sheet
Download: civilmdc.com/2020/03/09/stiff...
During an earthquake, failure of structure starts at points of weakness. This weakness arises due to discontinuity in mass, stiffness and geometry of structure. The structures having the discontinuity are termed as irregular structures.
Stiffness - Soft Story Irregularity:
It is defined to exist where there is a story in which the lateral stiffness is less than 70% of that in the story above or less than 80% of the average stiffness of the three stories above.
Stiffness - Extreme Soft Story Irregularity:
It is defined to exist where there is a story in which the lateral stiffness is less than 60% of that in the story above or less than 70% of the average stiffness of the three stories above.
As per ASCE 7 -16 Code (Chapter 12)
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Very useful information provided by you. Thank you
Excelente tutorial. El reporte que se obtiene del Etabs, ¿es el acumulado de cada piso?
Nice Series of Videos, really helpful for beginners.
Be blessed Bro
Excelent, thanks you.
Can you please help me ...
I am downloaded staad pro connect edition 22.0 ... from your site ..can I install it on 86bit or 32bit pc??
Please help me🙏
I have a problem that Story stiffness did not appear when I open structural results from tables!!
And I did not know why?
But how to make those formula in Excel....
Que hago si la tabla me sale en blanco y nose por que, ayuda por favor
JAZAKALLAH
outstanding work
Thanks
Excellent Tutorial...
Thanks dear Bro.
Nice work.
Plz include retaining walls in buildings including their analysis and design.
Thanks,
I have plan to complete the CSI ETABS Course, i will try to include basement walls (Retaining walls) in this course....
Hello, I have a doubt, when checking the story stiffness in the earthquake in the X direction, the Stiffness Y column does not result 0, and when checking stiffness in Y, the X column is also not 0
Stiffness is a constant value...
If you apply 1 kN force in X-direction or 100 kN..
Stiffness will remain same...
So that's in Y-direction it will come as it is....
Due to constant value
Thanks a lot sir .. Really helpful
Welcome 😇
Nice work! why the link "Stiffness Irregularity (soft story) excel sheet" is not working?
Website updated, now it is working
Is it necessary to include infill wall in the model? Bcoz it will add stiffness to the structure. So if there is an open ground floor and other story have infill wall then the ground floor may act as soft story. In that case, how to check soft story?
Answer 1
First of all it is not necessary....
Answer 2
2nd you have to calculate in the same as I have shown in this video.
Actually Etabs is not accurate in calculating storey stiffness because it does not consider infill walls. So in this case what you have done is not accurate. In case of having infill walls in above stories and open frames at ground level, the software consider all stories same but in reality infill walls have stiffness but the problem is how to calculate?
Dear Sir, Thank you for the video. I have a question; how can I calculate STIFFNESS in X-DIRECTION manually for a simple 2D steel building frame?
You have to calculate stiffness of each story by using stiffness formulas... That is given in your earthquake engineering books
@@civilmdc Dear Sir, thank you very much for the rapid response. I have a follow-up question; I have calculated the global stiffness matrix for a steel frame but I'm confused about calculating the stiffness for a particular floor level, can you please be more elaborate on what formula you are referring to. Or please provide a link to any documentation or paper related to stiffness calculation for a particular storey and direction.
How about only two storey building? The Upper Storey Ratio value is greater than 0.7, but failed in "Upper 3 Storey Ratio" which is less than 0.8. Since, there is only one storey existing above the first storey, should I ignore the 0.8, and only use 0.7 for soft storey irreg?
No need for 2 storey
Sir, how to get the story lateral strength in ETABS ? Thanks in advance
You can get lateral stiffness of each story
@@civilmdc I see.. lateral stiffness of each story can be obtained by dividing the story forces with story drift? And the lateral stiffness is directly proportional to the the lateral story strength?
Storey stiffness, K=EI/L
Becareful storey stiffness is different from storey strength
In 2 storey with elevated ground floor of 1.5m, I got soft storey in the first floor when actual roofing loads (steel trusses and roofing sheets) are included in the roof beam, but when I modeled roof deck (with minimum design loads), there's no soft storey (with ratio 0.8-0.85 > 0.7). So, I observed that when the weight carried by the roof beam is close to the weight carried by 2nd floor beam, there is no soft storey. When the weight carried by the beam is lighter, there is soft storey in the 1st floor. Why is that?
And also when I increase the column height in the 2nd floor, no soft storey exists.
No need to check for soft story .... For 2 story building
@@civilmdc why sir?
I live in a country with strong earthquakes. There are many two storey houses collapsed due to soft storey in the first floor
Is the process same for water tank to check stiffness
Yes
Unable to download the excel sheet. Can u pls update the link?
Sorry for Inconvenience,
All the links have been updated, Now you can download the excel sheets in the description of the videos.
Thanks
Thank u
can we have a video to check weak story also
CSI ETABS Essential Training Series full course
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Dear, the video in which you have commented, will give you all about how to check soft story in buildings ... Please see full video and excel sheet download link is given in the description.
@@civilmdc ubc says about weak story if the story strength is less than 80% of the story above can you please explain about this
Sir can you provide this excel sheet
Sure...
Dear excel sheet is present under the description of each video
@@civilmdc thank u so much sir
unable to download the excel sheet
Sorry for Inconvenience,
All the links have been updated, Now you can download the excel sheets in the description of the videos.
Thanks
Bundle of thanks bro... Allah bless you more. And thanks a lot for excel sheets 💕💕
@@civilmdcUnable to download excel files sir
how can we download excel sheet
Download link given on the description of the video
share excel sheet link pease
The link is given in the description of the video
pls provide google sheets
Dear link is given in the description of this video