CSI ETABS - 10 - Torsion Irregularity check | Part 2
In this lecture, Torsion Irregularity Check as per ASCE Part 2, example 2, is discussed.
1- Torsion Irregularity check excel sheet/spreadsheet
Download: civilmdc.com/2020/03/09/torsi...
2- ASCE 7-16 Minimum Design Loads and Associated Criteria for Buildings and Other Structures
Download: civilmdc.com/2020/03/09/asce-...
EXPLANATION:
a) Torsional Irregularity: Torsional irregularity is defined to exist where the maximum story drift, computed including accidental torsion with Ax =1.0, at one end of the structure transverse to an axis is more than 1.2 times the average of the story drifts at the two ends of the structure. Torsional irregularity requirements in the reference sections apply only to structures in which the diaphragms are rigid or semi-rigid.
b) Extreme Torsional Irregularity: Extreme torsional irregularity is defined to exist where the maximum story drift, computed including accidental torsion with Ax =1.0, at one end of the structure transverse to an axis is more than 1.4 times the average of the story drifts at the two ends of the structure. Extreme torsional irregularity requirements in the reference sections apply only to structures in which the diaphragms are rigid or semirigid.
To compute Torsional Irregularity and Extreme Torsional Irregularity, as specified in ASCE 7-16 Table 12.3-1, item 1a and 1b must be performed and shown in this video.
Structures assigned to Seismic Design Category C, D, E, or F,
where Type 1a or 1b torsional irregularity exists as defined in
Table 12.3-1 shall have the effects accounted for by multiplying
M at each level by a torsional amplification factor (Ax)
The torsional amplification factor (Ax) shall not be less than 1 and
is not required to exceed 3.0. The more severe loading for each
element shall be considered for design.
As per ASCE 7 - 16 Code
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Great work for Structural Engineers......Thank you very much God bless you...!
Good and clear!
bro u are doing great job... God bless u
@civilmdc
4 жыл бұрын
Thanks
JAZAKALLAH
If the building is 'L' shaped then what is the width of the building to be considered in X and Y direction.
Very useful knowledge given by you thanks sir.
@civilmdc
4 жыл бұрын
Thanks
👍🏻
Dear M Hussain, thank you for your valuable videos, Can you make a video on Base Shear and Overturning moment checks? supported by excel sheets based on ASCE7-16.. Regards,
What is DX?
thanks a lot it was useful
@civilmdc
10 ай бұрын
Welcome
Hy, I changed the eccentricity of the building after the analysis showed irregularity in torsional check. But still the results are the same, do I keep increasing/modifying the value of eccentricity for the building in the load pattern dialogue till the analysis says that the structure is regular ?
@inno5infra
4 ай бұрын
Same query.. please answer if u already got the solution.
sir my model have torsional irregularity after checking the irregularity I modified the eccentricity in x direction than I analysis the structure again ,after the analysis I get the same irregularity
@mdshahebazkhan-dv2od
Жыл бұрын
what do I do next sir
Hy, I changed the eccentricity of the building after the analysis showed irregularity in torsional check. But still the results are the same, do I keep increasing/modifying the value of eccentricity for the building in the load pattern dialogue till the analysis says that the structure is regular ? pl reply sir.
@sairaiqbal7647
3 ай бұрын
How much is irregularity? Share me value
@masoodhassan8600
3 ай бұрын
@@sairaiqbal7647 1.22 To 1.88
What is the code used in the design of this course?
@civilmdc
3 жыл бұрын
ASCE 7
Done subscribing
@civilmdc
4 жыл бұрын
Thanks
i think you should multiply with Lx for Qy and Ly for Qy
Dear, Thanks for the valuable video, Can you send me the Excel sheet because I can not download it correctly.
@civilmdc
7 ай бұрын
Please download with desktop... If you still face the issue... You can change browser... Like opera Firefox etc... Download link is given on the description of the video
Total eccentricity = e ± Ax*0.05*L Where L is the dimension of the structure perpendicular to the direction of the applied force? Is it correct?
@civilmdc
4 жыл бұрын
Yes Perpendicular to load
@cocoymagadia
4 жыл бұрын
@@civilmdc Please refer to UBC 97 Clause 1630.6 Where diaphragms are not flexible, the mass at each level shall be assumed to be displaced from the calculated center of mass in each direction a distance equal to 5 percent of the building dimension at that level perpendicular to the direction of the force under consideration. The effect of this displacement on the story shear distribution shall be considered
@civilmdc
4 жыл бұрын
@@cocoymagadia Dear you are right... On first look... i did not put attention on your question... now i am editing my answer.... Because in same direction of force, if eccentricity present.... then it will have an effect of eccentricity.
In the computation of the eccentricity absolute length... For Ex, should we not use the building dimension Dy not Dx... Same case with Ey, we should be using Dx as the building dimension... Kindly clarify and make the necessary adjustments, so that the group will be guided accordingly. Thnx
@saleheencebuet
3 ай бұрын
You are right
It's not max drift ratio in IS code,, it's middle and avrg ratio not more 1.2, can any please clearify as per IS CODE
@civilmdc
2 жыл бұрын
It is as per ASCE 7-16
Why you used UBC 97 but in calculation you used Asce 7-16?
@civilmdc
4 жыл бұрын
Dear Structural torsional Irregularity is same in both codes.
@engrgep
4 жыл бұрын
@@civilmdc thank you. More powers to your channel.
@civilmdc
4 жыл бұрын
@@engrgep thanks dear.... For Appreciative feedback
Dear Mr. Engineer. i think you might be mistaken in calculation of Ax because you have to use the MAx and Avg displacements to calculate it not the drift as you did
@civilmdc
Жыл бұрын
Dear excel sheet is attached in the description... You can check with ASCE Code..
Sire … Is this building designed according to ACI code?
@civilmdc
Жыл бұрын
Yes, this course is as per ACI Here is the full course link on CSI ETABS kzread.info/head/PL0h14oMuZXQ5PXbux0l80ox-8gPwcBl5c
@mohamedag8366
Жыл бұрын
@@civilmdc thanks. How many Excel sheet this Includes ?
@civilmdc
Жыл бұрын
@@mohamedag8366 if any excel sheet discuss in the lecture...then it's download link is given in the description of the video
@mohamedag8366
Жыл бұрын
@@civilmdc if I want to check P-Delta for shear wall , Am I following the same steps for columns like in your video?